diff options
Diffstat (limited to 'Documentation')
69 files changed, 1633 insertions, 187 deletions
diff --git a/Documentation/00-INDEX b/Documentation/00-INDEX index 1b777b9..1f89424 100644 --- a/Documentation/00-INDEX +++ b/Documentation/00-INDEX @@ -192,10 +192,6 @@ kernel-docs.txt - listing of various WWW + books that document kernel internals. kernel-parameters.txt - summary listing of command line / boot prompt args for the kernel. -keys-request-key.txt - - description of the kernel key request service. -keys.txt - - description of the kernel key retention service. kobject.txt - info of the kobject infrastructure of the Linux kernel. kprobes.txt @@ -294,6 +290,8 @@ scheduler/ - directory with info on the scheduler. scsi/ - directory with info on Linux scsi support. +security/ + - directory that contains security-related info serial/ - directory with info on the low level serial API. serial-console.txt diff --git a/Documentation/ABI/obsolete/o2cb b/Documentation/ABI/removed/o2cb index 9c49d8e..7f5daa4 100644 --- a/Documentation/ABI/obsolete/o2cb +++ b/Documentation/ABI/removed/o2cb @@ -1,11 +1,10 @@ What: /sys/o2cb symlink -Date: Dec 2005 -KernelVersion: 2.6.16 +Date: May 2011 +KernelVersion: 2.6.40 Contact: ocfs2-devel@oss.oracle.com -Description: This is a symlink: /sys/o2cb to /sys/fs/o2cb. The symlink will - be removed when new versions of ocfs2-tools which know to look +Description: This is a symlink: /sys/o2cb to /sys/fs/o2cb. The symlink is + removed when new versions of ocfs2-tools which know to look in /sys/fs/o2cb are sufficiently prevalent. Don't code new software to look here, it should try /sys/fs/o2cb instead. - See Documentation/ABI/stable/o2cb for more information on usage. Users: ocfs2-tools. It's sufficient to mail proposed changes to ocfs2-devel@oss.oracle.com. diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 4873c75..c1eb41c 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -142,3 +142,67 @@ Description: with the previous I/O request are enabled. When set to 2, all merge tries are disabled. The default value is 0 - which enables all types of merge tries. + +What: /sys/block/<disk>/discard_alignment +Date: May 2011 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Devices that support discard functionality may + internally allocate space in units that are bigger than + the exported logical block size. The discard_alignment + parameter indicates how many bytes the beginning of the + device is offset from the internal allocation unit's + natural alignment. + +What: /sys/block/<disk>/<partition>/discard_alignment +Date: May 2011 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Devices that support discard functionality may + internally allocate space in units that are bigger than + the exported logical block size. The discard_alignment + parameter indicates how many bytes the beginning of the + partition is offset from the internal allocation unit's + natural alignment. + +What: /sys/block/<disk>/queue/discard_granularity +Date: May 2011 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Devices that support discard functionality may + internally allocate space using units that are bigger + than the logical block size. The discard_granularity + parameter indicates the size of the internal allocation + unit in bytes if reported by the device. Otherwise the + discard_granularity will be set to match the device's + physical block size. A discard_granularity of 0 means + that the device does not support discard functionality. + +What: /sys/block/<disk>/queue/discard_max_bytes +Date: May 2011 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Devices that support discard functionality may have + internal limits on the number of bytes that can be + trimmed or unmapped in a single operation. Some storage + protocols also have inherent limits on the number of + blocks that can be described in a single command. The + discard_max_bytes parameter is set by the device driver + to the maximum number of bytes that can be discarded in + a single operation. Discard requests issued to the + device must not exceed this limit. A discard_max_bytes + value of 0 means that the device does not support + discard functionality. + +What: /sys/block/<disk>/queue/discard_zeroes_data +Date: May 2011 +Contact: Martin K. Petersen <martin.petersen@oracle.com> +Description: + Devices that support discard functionality may return + stale or random data when a previously discarded block + is read back. This can cause problems if the filesystem + expects discarded blocks to be explicitly cleared. If a + device reports that it deterministically returns zeroes + when a discarded area is read the discard_zeroes_data + parameter will be set to one. Otherwise it will be 0 and + the result of reading a discarded area is undefined. diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-cleancache b/Documentation/ABI/testing/sysfs-kernel-mm-cleancache new file mode 100644 index 0000000..662ae64 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-cleancache @@ -0,0 +1,11 @@ +What: /sys/kernel/mm/cleancache/ +Date: April 2011 +Contact: Dan Magenheimer <dan.magenheimer@oracle.com> +Description: + /sys/kernel/mm/cleancache/ contains a number of files which + record a count of various cleancache operations + (sum across all filesystems): + succ_gets + failed_gets + puts + flushes diff --git a/Documentation/ABI/testing/sysfs-ptp b/Documentation/ABI/testing/sysfs-ptp new file mode 100644 index 0000000..d40d2b5 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-ptp @@ -0,0 +1,98 @@ +What: /sys/class/ptp/ +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This directory contains files and directories + providing a standardized interface to the ancillary + features of PTP hardware clocks. + +What: /sys/class/ptp/ptpN/ +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This directory contains the attributes of the Nth PTP + hardware clock registered into the PTP class driver + subsystem. + +What: /sys/class/ptp/ptpN/clock_name +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file contains the name of the PTP hardware clock + as a human readable string. + +What: /sys/class/ptp/ptpN/max_adjustment +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file contains the PTP hardware clock's maximum + frequency adjustment value (a positive integer) in + parts per billion. + +What: /sys/class/ptp/ptpN/n_alarms +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file contains the number of periodic or one shot + alarms offer by the PTP hardware clock. + +What: /sys/class/ptp/ptpN/n_external_timestamps +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file contains the number of external timestamp + channels offered by the PTP hardware clock. + +What: /sys/class/ptp/ptpN/n_periodic_outputs +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file contains the number of programmable periodic + output channels offered by the PTP hardware clock. + +What: /sys/class/ptp/ptpN/pps_avaiable +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file indicates whether the PTP hardware clock + supports a Pulse Per Second to the host CPU. Reading + "1" means that the PPS is supported, while "0" means + not supported. + +What: /sys/class/ptp/ptpN/extts_enable +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This write-only file enables or disables external + timestamps. To enable external timestamps, write the + channel index followed by a "1" into the file. + To disable external timestamps, write the channel + index followed by a "0" into the file. + +What: /sys/class/ptp/ptpN/fifo +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This file provides timestamps on external events, in + the form of three integers: channel index, seconds, + and nanoseconds. + +What: /sys/class/ptp/ptpN/period +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This write-only file enables or disables periodic + outputs. To enable a periodic output, write five + integers into the file: channel index, start time + seconds, start time nanoseconds, period seconds, and + period nanoseconds. To disable a periodic output, set + all the seconds and nanoseconds values to zero. + +What: /sys/class/ptp/ptpN/pps_enable +Date: September 2010 +Contact: Richard Cochran <richardcochran@gmail.com> +Description: + This write-only file enables or disables delivery of + PPS events to the Linux PPS subsystem. To enable PPS + events, write a "1" into the file. To disable events, + write a "0" into the file. diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index 8436b01..3cebfa0 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -73,7 +73,7 @@ installmandocs: mandocs ### #External programs used KERNELDOC = $(srctree)/scripts/kernel-doc -DOCPROC = $(objtree)/scripts/basic/docproc +DOCPROC = $(objtree)/scripts/docproc XMLTOFLAGS = -m $(srctree)/Documentation/DocBook/stylesheet.xsl XMLTOFLAGS += --skip-validation diff --git a/Documentation/DocBook/dvb/dvbproperty.xml b/Documentation/DocBook/dvb/dvbproperty.xml index 52d5e3c..b5365f6 100644 --- a/Documentation/DocBook/dvb/dvbproperty.xml +++ b/Documentation/DocBook/dvb/dvbproperty.xml @@ -141,13 +141,15 @@ struct dtv_properties { </row></tbody></tgroup></informaltable> </section> +<section> + <title>Property types</title> <para> On <link linkend="FE_GET_PROPERTY">FE_GET_PROPERTY</link>/<link linkend="FE_SET_PROPERTY">FE_SET_PROPERTY</link>, the actual action is determined by the dtv_property cmd/data pairs. With one single ioctl, is possible to get/set up to 64 properties. The actual meaning of each property is described on the next sections. </para> -<para>The Available frontend property types are:</para> +<para>The available frontend property types are:</para> <programlisting> #define DTV_UNDEFINED 0 #define DTV_TUNE 1 @@ -193,6 +195,7 @@ get/set up to 64 properties. The actual meaning of each property is described on #define DTV_ISDBT_LAYER_ENABLED 41 #define DTV_ISDBS_TS_ID 42 </programlisting> +</section> <section id="fe_property_common"> <title>Parameters that are common to all Digital TV standards</title> diff --git a/Documentation/DocBook/media-entities.tmpl b/Documentation/DocBook/media-entities.tmpl index c8abb23..e5fe094 100644 --- a/Documentation/DocBook/media-entities.tmpl +++ b/Documentation/DocBook/media-entities.tmpl @@ -293,6 +293,7 @@ <!ENTITY sub-yuyv SYSTEM "v4l/pixfmt-yuyv.xml"> <!ENTITY sub-yvyu SYSTEM "v4l/pixfmt-yvyu.xml"> <!ENTITY sub-srggb10 SYSTEM "v4l/pixfmt-srggb10.xml"> +<!ENTITY sub-srggb12 SYSTEM "v4l/pixfmt-srggb12.xml"> <!ENTITY sub-srggb8 SYSTEM "v4l/pixfmt-srggb8.xml"> <!ENTITY sub-y10 SYSTEM "v4l/pixfmt-y10.xml"> <!ENTITY sub-y12 SYSTEM "v4l/pixfmt-y12.xml"> @@ -373,9 +374,9 @@ <!ENTITY sub-media-indices SYSTEM "media-indices.tmpl"> <!ENTITY sub-media-controller SYSTEM "v4l/media-controller.xml"> -<!ENTITY sub-media-open SYSTEM "v4l/media-func-open.xml"> -<!ENTITY sub-media-close SYSTEM "v4l/media-func-close.xml"> -<!ENTITY sub-media-ioctl SYSTEM "v4l/media-func-ioctl.xml"> +<!ENTITY sub-media-func-open SYSTEM "v4l/media-func-open.xml"> +<!ENTITY sub-media-func-close SYSTEM "v4l/media-func-close.xml"> +<!ENTITY sub-media-func-ioctl SYSTEM "v4l/media-func-ioctl.xml"> <!ENTITY sub-media-ioc-device-info SYSTEM "v4l/media-ioc-device-info.xml"> <!ENTITY sub-media-ioc-enum-entities SYSTEM "v4l/media-ioc-enum-entities.xml"> <!ENTITY sub-media-ioc-enum-links SYSTEM "v4l/media-ioc-enum-links.xml"> diff --git a/Documentation/DocBook/v4l/media-controller.xml b/Documentation/DocBook/v4l/media-controller.xml index 2dc25e1..873ac3a 100644 --- a/Documentation/DocBook/v4l/media-controller.xml +++ b/Documentation/DocBook/v4l/media-controller.xml @@ -78,9 +78,9 @@ <appendix id="media-user-func"> <title>Function Reference</title> <!-- Keep this alphabetically sorted. --> - &sub-media-open; - &sub-media-close; - &sub-media-ioctl; + &sub-media-func-open; + &sub-media-func-close; + &sub-media-func-ioctl; <!-- All ioctls go here. --> &sub-media-ioc-device-info; &sub-media-ioc-enum-entities; diff --git a/Documentation/DocBook/v4l/pixfmt.xml b/Documentation/DocBook/v4l/pixfmt.xml index dbfe3b0..deb6602 100644 --- a/Documentation/DocBook/v4l/pixfmt.xml +++ b/Documentation/DocBook/v4l/pixfmt.xml @@ -673,6 +673,7 @@ access the palette, this must be done with ioctls of the Linux framebuffer API.< &sub-srggb8; &sub-sbggr16; &sub-srggb10; + &sub-srggb12; </section> <section id="yuv-formats"> diff --git a/Documentation/DocBook/v4l/subdev-formats.xml b/Documentation/DocBook/v4l/subdev-formats.xml index a26b10c..8d3409d 100644 --- a/Documentation/DocBook/v4l/subdev-formats.xml +++ b/Documentation/DocBook/v4l/subdev-formats.xml @@ -2531,13 +2531,13 @@ <constant>_JPEG</constant> prefix the format code is made of the following information. <itemizedlist> - <listitem>The number of bus samples per entropy encoded byte.</listitem> - <listitem>The bus width.</listitem> + <listitem><para>The number of bus samples per entropy encoded byte.</para></listitem> + <listitem><para>The bus width.</para></listitem> </itemizedlist> + </para> - <para>For instance, for a JPEG baseline process and an 8-bit bus width - the format will be named <constant>V4L2_MBUS_FMT_JPEG_1X8</constant>. - </para> + <para>For instance, for a JPEG baseline process and an 8-bit bus width + the format will be named <constant>V4L2_MBUS_FMT_JPEG_1X8</constant>. </para> <para>The following table lists existing JPEG compressed formats.</para> diff --git a/Documentation/IRQ-affinity.txt b/Documentation/IRQ-affinity.txt index b4a615b..7890fae 100644 --- a/Documentation/IRQ-affinity.txt +++ b/Documentation/IRQ-affinity.txt @@ -4,10 +4,11 @@ ChangeLog: SMP IRQ affinity -/proc/irq/IRQ#/smp_affinity specifies which target CPUs are permitted -for a given IRQ source. It's a bitmask of allowed CPUs. It's not allowed -to turn off all CPUs, and if an IRQ controller does not support IRQ -affinity then the value will not change from the default 0xffffffff. +/proc/irq/IRQ#/smp_affinity and /proc/irq/IRQ#/smp_affinity_list specify +which target CPUs are permitted for a given IRQ source. It's a bitmask +(smp_affinity) or cpu list (smp_affinity_list) of allowed CPUs. It's not +allowed to turn off all CPUs, and if an IRQ controller does not support +IRQ affinity then the value will not change from the default of all cpus. /proc/irq/default_smp_affinity specifies default affinity mask that applies to all non-active IRQs. Once IRQ is allocated/activated its affinity bitmask @@ -54,3 +55,11 @@ round-trip min/avg/max = 0.1/0.5/585.4 ms This time around IRQ44 was delivered only to the last four processors. i.e counters for the CPU0-3 did not change. +Here is an example of limiting that same irq (44) to cpus 1024 to 1031: + +[root@moon 44]# echo 1024-1031 > smp_affinity +[root@moon 44]# cat smp_affinity +1024-1031 + +Note that to do this with a bitmask would require 32 bitmasks of zero +to follow the pertinent one. diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c index e9c7778..f6318f6 100644 --- a/Documentation/accounting/getdelays.c +++ b/Documentation/accounting/getdelays.c @@ -177,6 +177,8 @@ static int get_family_id(int sd) rc = send_cmd(sd, GENL_ID_CTRL, getpid(), CTRL_CMD_GETFAMILY, CTRL_ATTR_FAMILY_NAME, (void *)name, strlen(TASKSTATS_GENL_NAME)+1); + if (rc < 0) + return 0; /* sendto() failure? */ rep_len = recv(sd, &ans, sizeof(ans), 0); if (ans.n.nlmsg_type == NLMSG_ERROR || @@ -191,30 +193,37 @@ static int get_family_id(int sd) return id; } +#define average_ms(t, c) (t / 1000000ULL / (c ? c : 1)) + static void print_delayacct(struct taskstats *t) { - printf("\n\nCPU %15s%15s%15s%15s\n" - " %15llu%15llu%15llu%15llu\n" - "IO %15s%15s\n" - " %15llu%15llu\n" - "SWAP %15s%15s\n" - " %15llu%15llu\n" - "RECLAIM %12s%15s\n" - " %15llu%15llu\n", - "count", "real total", "virtual total", "delay total", + printf("\n\nCPU %15s%15s%15s%15s%15s\n" + " %15llu%15llu%15llu%15llu%15.3fms\n" + "IO %15s%15s%15s\n" + " %15llu%15llu%15llums\n" + "SWAP %15s%15s%15s\n" + " %15llu%15llu%15llums\n" + "RECLAIM %12s%15s%15s\n" + " %15llu%15llu%15llums\n", + "count", "real total", "virtual total", + "delay total", "delay average", (unsigned long long)t->cpu_count, (unsigned long long)t->cpu_run_real_total, (unsigned long long)t->cpu_run_virtual_total, (unsigned long long)t->cpu_delay_total, - "count", "delay total", + average_ms((double)t->cpu_delay_total, t->cpu_count), + "count", "delay total", "delay average", (unsigned long long)t->blkio_count, (unsigned long long)t->blkio_delay_total, - "count", "delay total", + average_ms(t->blkio_delay_total, t->blkio_count), + "count", "delay total", "delay average", (unsigned long long)t->swapin_count, (unsigned long long)t->swapin_delay_total, - "count", "delay total", + average_ms(t->swapin_delay_total, t->swapin_count), + "count", "delay total", "delay average", (unsigned long long)t->freepages_count, - (unsigned long long)t->freepages_delay_total); + (unsigned long long)t->freepages_delay_total, + average_ms(t->freepages_delay_total, t->freepages_count)); } static void task_context_switch_counts(struct taskstats *t) @@ -433,8 +442,6 @@ int main(int argc, char *argv[]) } do { - int i; - rep_len = recv(nl_sd, &msg, sizeof(msg), 0); PRINTF("received %d bytes\n", rep_len); @@ -459,7 +466,6 @@ int main(int argc, char *argv[]) na = (struct nlattr *) GENLMSG_DATA(&msg); len = 0; - i = 0; while (len < rep_len) { len += NLA_ALIGN(na->nla_len); switch (na->nla_type) { diff --git a/Documentation/arm/Booting b/Documentation/arm/Booting index 7685029..4e686a2 100644 --- a/Documentation/arm/Booting +++ b/Documentation/arm/Booting @@ -65,13 +65,19 @@ looks at the connected hardware is beyond the scope of this document. The boot loader must ultimately be able to provide a MACH_TYPE_xxx value to the kernel. (see linux/arch/arm/tools/mach-types). - -4. Setup the kernel tagged list -------------------------------- +4. Setup boot data +------------------ Existing boot loaders: OPTIONAL, HIGHLY RECOMMENDED New boot loaders: MANDATORY +The boot loader must provide either a tagged list or a dtb image for +passing configuration data to the kernel. The physical address of the +boot data is passed to the kernel in register r2. + +4a. Setup the kernel tagged list +-------------------------------- + The boot loader must create and initialise the kernel tagged list. A valid tagged list starts with ATAG_CORE and ends with ATAG_NONE. The ATAG_CORE tag may or may not be empty. An empty ATAG_CORE tag @@ -101,6 +107,24 @@ The tagged list must be placed in a region of memory where neither the kernel decompressor nor initrd 'bootp' program will overwrite it. The recommended placement is in the first 16KiB of RAM. +4b. Setup the device tree +------------------------- + +The boot loader must load a device tree image (dtb) into system ram +at a 64bit aligned address and initialize it with the boot data. The +dtb format is documented in Documentation/devicetree/booting-without-of.txt. +The kernel will look for the dtb magic value of 0xd00dfeed at the dtb +physical address to determine if a dtb has been passed instead of a +tagged list. + +The boot loader must pass at a minimum the size and location of the +system memory, and the root filesystem location. The dtb must be +placed in a region of memory where the kernel decompressor will not +overwrite it. The recommended placement is in the first 16KiB of RAM +with the caveat that it may not be located at physical address 0 since +the kernel interprets a value of 0 in r2 to mean neither a tagged list +nor a dtb were passed. + 5. Calling the kernel image --------------------------- @@ -125,7 +149,8 @@ In either case, the following conditions must be met: - CPU register settings r0 = 0, r1 = machine type number discovered in (3) above. - r2 = physical address of tagged list in system RAM. + r2 = physical address of tagged list in system RAM, or + physical address of device tree block (dtb) in system RAM - CPU mode All forms of interrupts must be disabled (IRQs and FIQs) diff --git a/Documentation/arm/Samsung/Overview.txt b/Documentation/arm/Samsung/Overview.txt index c3094ea..658abb2 100644 --- a/Documentation/arm/Samsung/Overview.txt +++ b/Documentation/arm/Samsung/Overview.txt @@ -14,7 +14,6 @@ Introduction - S3C24XX: See Documentation/arm/Samsung-S3C24XX/Overview.txt for full list - S3C64XX: S3C6400 and S3C6410 - S5P6440 - - S5P6442 - S5PC100 - S5PC110 / S5PV210 @@ -36,7 +35,6 @@ Configuration unifying all the SoCs into one kernel. s5p6440_defconfig - S5P6440 specific default configuration - s5p6442_defconfig - S5P6442 specific default configuration s5pc100_defconfig - S5PC100 specific default configuration s5pc110_defconfig - S5PC110 specific default configuration s5pv210_defconfig - S5PV210 specific default configuration diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt index ac4d471..3bd585b 100644 --- a/Documentation/atomic_ops.txt +++ b/Documentation/atomic_ops.txt @@ -12,7 +12,7 @@ Also, it should be made opaque such that any kind of cast to a normal C integer type will fail. Something like the following should suffice: - typedef struct { volatile int counter; } atomic_t; + typedef struct { int counter; } atomic_t; Historically, counter has been declared volatile. This is now discouraged. See Documentation/volatile-considered-harmful.txt for the complete rationale. diff --git a/Documentation/blockdev/cciss.txt b/Documentation/blockdev/cciss.txt index 89698e8..c00c6a5 100644 --- a/Documentation/blockdev/cciss.txt +++ b/Documentation/blockdev/cciss.txt @@ -169,3 +169,18 @@ is issued which positions the tape to a known position. Typically you must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example) before i/o can proceed again to a tape drive which was reset. +There is a cciss_tape_cmds module parameter which can be used to make cciss +allocate more commands for use by tape drives. Ordinarily only a few commands +(6) are allocated for tape drives because tape drives are slow and +infrequently used and the primary purpose of Smart Array controllers is to +act as a RAID controller for disk drives, so the vast majority of commands +are allocated for disk devices. However, if you have more than a few tape +drives attached to a smart array, the default number of commands may not be +enought (for example, if you have 8 tape drives, you could only rewind 6 +at one time with the default number of commands.) The cciss_tape_cmds module +parameter allows more commands (up to 16 more) to be allocated for use by +tape drives. For example: + + insmod cciss.ko cciss_tape_cmds=16 + +Or, as a kernel boot parameter passed in via grub: cciss.cciss_tape_cmds=8 diff --git a/Documentation/cachetlb.txt b/Documentation/cachetlb.txt index 9164ae3..9b728dc 100644 --- a/Documentation/cachetlb.txt +++ b/Documentation/cachetlb.txt @@ -16,7 +16,7 @@ on all processors in the system. Don't let this scare you into thinking SMP cache/tlb flushing must be so inefficient, this is in fact an area where many optimizations are possible. For example, if it can be proven that a user address space has never executed -on a cpu (see vma->cpu_vm_mask), one need not perform a flush +on a cpu (see mm_cpumask()), one need not perform a flush for this address space on that cpu. First, the TLB flushing interfaces, since they are the simplest. The diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index aedf1bd..0ed99f0 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -236,7 +236,8 @@ containing the following files describing that cgroup: - cgroup.procs: list of tgids in the cgroup. This list is not guaranteed to be sorted or free of duplicate tgids, and userspace should sort/uniquify the list if this property is required. - This is a read-only file, for now. + Writing a thread group id into this file moves all threads in that + group into this cgroup. - notify_on_release flag: run the release agent on exit? - release_agent: the path to use for release notifications (this file exists in the top cgroup only) @@ -430,6 +431,12 @@ You can attach the current shell task by echoing 0: # echo 0 > tasks +You can use the cgroup.procs file instead of the tasks file to move all +threads in a threadgroup at once. Echoing the pid of any task in a +threadgroup to cgroup.procs causes all tasks in that threadgroup to be +be attached to the cgroup. Writing 0 to cgroup.procs moves all tasks +in the writing task's threadgroup. + Note: Since every task is always a member of exactly one cgroup in each mounted hierarchy, to remove a task from its current cgroup you must move it into a new cgroup (possibly the root cgroup) by writing to the @@ -575,7 +582,7 @@ rmdir() will fail with it. From this behavior, pre_destroy() can be called multiple times against a cgroup. int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct task_struct *task, bool threadgroup) + struct task_struct *task) (cgroup_mutex held by caller) Called prior to moving a task into a cgroup; if the subsystem @@ -584,9 +591,14 @@ task is passed, then a successful result indicates that *any* unspecified task can be moved into the cgroup. Note that this isn't called on a fork. If this method returns 0 (success) then this should remain valid while the caller holds cgroup_mutex and it is ensured that either -attach() or cancel_attach() will be called in future. If threadgroup is -true, then a successful result indicates that all threads in the given -thread's threadgroup can be moved together. +attach() or cancel_attach() will be called in future. + +int can_attach_task(struct cgroup *cgrp, struct task_struct *tsk); +(cgroup_mutex held by caller) + +As can_attach, but for operations that must be run once per task to be +attached (possibly many when using cgroup_attach_proc). Called after +can_attach. void cancel_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, struct task_struct *task, bool threadgroup) @@ -598,15 +610,24 @@ function, so that the subsystem can implement a rollback. If not, not necessary. This will be called only about subsystems whose can_attach() operation have succeeded. +void pre_attach(struct cgroup *cgrp); +(cgroup_mutex held by caller) + +For any non-per-thread attachment work that needs to happen before +attach_task. Needed by cpuset. + void attach(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct cgroup *old_cgrp, struct task_struct *task, - bool threadgroup) + struct cgroup *old_cgrp, struct task_struct *task) (cgroup_mutex held by caller) Called after the task has been attached to the cgroup, to allow any post-attachment activity that requires memory allocations or blocking. -If threadgroup is true, the subsystem should take care of all threads -in the specified thread's threadgroup. Currently does not support any + +void attach_task(struct cgroup *cgrp, struct task_struct *tsk); +(cgroup_mutex held by caller) + +As attach, but for operations that must be run once per task to be attached, +like can_attach_task. Called before attach. Currently does not support any subsystem that might need the old_cgrp for every thread in the group. void fork(struct cgroup_subsy *ss, struct task_struct *task) @@ -630,7 +651,7 @@ always handled well. void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp) (cgroup_mutex held by caller) -Called at the end of cgroup_clone() to do any parameter +Called during cgroup_create() to do any parameter initialization which might be required before a task could attach. For example in cpusets, no task may attach before 'cpus' and 'mems' are set up. diff --git a/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt b/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt index edb7ae1..2c6be03 100644 --- a/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt +++ b/Documentation/devicetree/bindings/net/fsl-tsec-phy.txt @@ -74,3 +74,57 @@ Example: interrupt-parent = <&mpic>; phy-handle = <&phy0> }; + +* Gianfar PTP clock nodes + +General Properties: + + - compatible Should be "fsl,etsec-ptp" + - reg Offset and length of the register set for the device + - interrupts There should be at least two interrupts. Some devices + have as many as four PTP related interrupts. + +Clock Properties: + + - fsl,tclk-period Timer reference clock period in nanoseconds. + - fsl,tmr-prsc Prescaler, divides the output clock. + - fsl,tmr-add Frequency compensation value. + - fsl,tmr-fiper1 Fixed interval period pulse generator. + - fsl,tmr-fiper2 Fixed interval period pulse generator. + - fsl,max-adj Maximum frequency adjustment in parts per billion. + + These properties set the operational parameters for the PTP + clock. You must choose these carefully for the clock to work right. + Here is how to figure good values: + + TimerOsc = system clock MHz + tclk_period = desired clock period nanoseconds + NominalFreq = 1000 / tclk_period MHz + FreqDivRatio = TimerOsc / NominalFreq (must be greater that 1.0) + tmr_add = ceil(2^32 / FreqDivRatio) + OutputClock = NominalFreq / tmr_prsc MHz + PulseWidth = 1 / OutputClock microseconds + FiperFreq1 = desired frequency in Hz + FiperDiv1 = 1000000 * OutputClock / FiperFreq1 + tmr_fiper1 = tmr_prsc * tclk_period * FiperDiv1 - tclk_period + max_adj = 1000000000 * (FreqDivRatio - 1.0) - 1 + + The calculation for tmr_fiper2 is the same as for tmr_fiper1. The + driver expects that tmr_fiper1 will be correctly set to produce a 1 + Pulse Per Second (PPS) signal, since this will be offered to the PPS + subsystem to synchronize the Linux clock. + +Example: + + ptp_clock@24E00 { + compatible = "fsl,etsec-ptp"; + reg = <0x24E00 0xB0>; + interrupts = <12 0x8 13 0x8>; + interrupt-parent = < &ipic >; + fsl,tclk-period = <10>; + fsl,tmr-prsc = <100>; + fsl,tmr-add = <0x999999A4>; + fsl,tmr-fiper1 = <0x3B9AC9F6>; + fsl,tmr-fiper2 = <0x00018696>; + fsl,max-adj = <659999998>; + }; diff --git a/Documentation/devicetree/booting-without-of.txt b/Documentation/devicetree/booting-without-of.txt index 50619a0..7c1329d 100644 --- a/Documentation/devicetree/booting-without-of.txt +++ b/Documentation/devicetree/booting-without-of.txt @@ -12,8 +12,9 @@ Table of Contents ================= I - Introduction - 1) Entry point for arch/powerpc - 2) Entry point for arch/x86 + 1) Entry point for arch/arm + 2) Entry point for arch/powerpc + 3) Entry point for arch/x86 II - The DT block format 1) Header @@ -148,7 +149,46 @@ upgrades without significantly impacting the kernel code or cluttering it with special cases. -1) Entry point for arch/powerpc +1) Entry point for arch/arm +--------------------------- + + There is one single entry point to the kernel, at the start + of the kernel image. That entry point supports two calling + conventions. A summary of the interface is described here. A full + description of the boot requirements is documented in + Documentation/arm/Booting + + a) ATAGS interface. Minimal information is passed from firmware + to the kernel with a tagged list of predefined parameters. + + r0 : 0 + + r1 : Machine type number + + r2 : Physical address of tagged list in system RAM + + b) Entry with a flattened device-tree block. Firmware loads the + physical address of the flattened device tree block (dtb) into r2, + r1 is not used, but it is considered good practise to use a valid + machine number as described in Documentation/arm/Booting. + + r0 : 0 + + r1 : Valid machine type number. When using a device tree, + a single machine type number will often be assigned to + represent a class or family of SoCs. + + r2 : physical pointer to the device-tree block + (defined in chapter II) in RAM. Device tree can be located + anywhere in system RAM, but it should be aligned on a 64 bit + boundary. + + The kernel will differentiate between ATAGS and device tree booting by + reading the memory pointed to by r2 and looking for either the flattened + device tree block magic value (0xd00dfeed) or the ATAG_CORE value at + offset 0x4 from r2 (0x54410001). + +2) Entry point for arch/powerpc ------------------------------- There is one single entry point to the kernel, at the start @@ -226,7 +266,7 @@ it with special cases. cannot support both configurations with Book E and configurations with classic Powerpc architectures. -2) Entry point for arch/x86 +3) Entry point for arch/x86 ------------------------------- There is one single 32bit entry point to the kernel at code32_start, diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 95788ad..ff31b1c 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -262,16 +262,6 @@ Who: Michael Buesch <mb@bu3sch.de> --------------------------- -What: /sys/o2cb symlink -When: January 2010 -Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb - exists as a symlink for backwards compatibility for old versions of - ocfs2-tools. 2 years should be sufficient time to phase in new versions - which know to look in /sys/fs/o2cb. -Who: ocfs2-devel@oss.oracle.com - ---------------------------- - What: Ability for non root users to shm_get hugetlb pages based on mlock resource limits When: 2.6.31 diff --git a/Documentation/filesystems/9p.txt b/Documentation/filesystems/9p.txt index b22abba..13de64c 100644 --- a/Documentation/filesystems/9p.txt +++ b/Documentation/filesystems/9p.txt @@ -25,6 +25,8 @@ Other applications are described in the following papers: http://xcpu.org/papers/cellfs-talk.pdf * PROSE I/O: Using 9p to enable Application Partitions http://plan9.escet.urjc.es/iwp9/cready/PROSE_iwp9_2006.pdf + * VirtFS: A Virtualization Aware File System pass-through + http://goo.gl/3WPDg USAGE ===== @@ -130,31 +132,20 @@ OPTIONS RESOURCES ========= -Our current recommendation is to use Inferno (http://www.vitanuova.com/nferno/index.html) -as the 9p server. You can start a 9p server under Inferno by issuing the -following command: - ; styxlisten -A tcp!*!564 export '#U*' +Protocol specifications are maintained on github: +http://ericvh.github.com/9p-rfc/ -The -A specifies an unauthenticated export. The 564 is the port # (you may -have to choose a higher port number if running as a normal user). The '#U*' -specifies exporting the root of the Linux name space. You may specify a -subset of the namespace by extending the path: '#U*'/tmp would just export -/tmp. For more information, see the Inferno manual pages covering styxlisten -and export. +9p client and server implementations are listed on +http://9p.cat-v.org/implementations -A Linux version of the 9p server is now maintained under the npfs project -on sourceforge (http://sourceforge.net/projects/npfs). The currently -maintained version is the single-threaded version of the server (named spfs) -available from the same SVN repository. +A 9p2000.L server is being developed by LLNL and can be found +at http://code.google.com/p/diod/ There are user and developer mailing lists available through the v9fs project on sourceforge (http://sourceforge.net/projects/v9fs). -A stand-alone version of the module (which should build for any 2.6 kernel) -is available via (http://github.com/ericvh/9p-sac/tree/master) - -News and other information is maintained on SWiK (http://swik.net/v9fs) -and the Wiki (http://sf.net/apps/mediawiki/v9fs/index.php). +News and other information is maintained on a Wiki. +(http://sf.net/apps/mediawiki/v9fs/index.php). Bug reports may be issued through the kernel.org bugzilla (http://bugzilla.kernel.org) diff --git a/Documentation/filesystems/configfs/configfs_example_explicit.c b/Documentation/filesystems/configfs/configfs_example_explicit.c index fd53869f..1420233 100644 --- a/Documentation/filesystems/configfs/configfs_example_explicit.c +++ b/Documentation/filesystems/configfs/configfs_example_explicit.c @@ -464,9 +464,8 @@ static int __init configfs_example_init(void) return 0; out_unregister: - for (; i >= 0; i--) { + for (i--; i >= 0; i--) configfs_unregister_subsystem(example_subsys[i]); - } return ret; } @@ -475,9 +474,8 @@ static void __exit configfs_example_exit(void) { int i; - for (i = 0; example_subsys[i]; i++) { + for (i = 0; example_subsys[i]; i++) configfs_unregister_subsystem(example_subsys[i]); - } } module_init(configfs_example_init); diff --git a/Documentation/filesystems/configfs/configfs_example_macros.c b/Documentation/filesystems/configfs/configfs_example_macros.c index d8e30a0..327dfbc 100644 --- a/Documentation/filesystems/configfs/configfs_example_macros.c +++ b/Documentation/filesystems/configfs/configfs_example_macros.c @@ -427,9 +427,8 @@ static int __init configfs_example_init(void) return 0; out_unregister: - for (; i >= 0; i--) { + for (i--; i >= 0; i--) configfs_unregister_subsystem(example_subsys[i]); - } return ret; } @@ -438,9 +437,8 @@ static void __exit configfs_example_exit(void) { int i; - for (i = 0; example_subsys[i]; i++) { + for (i = 0; example_subsys[i]; i++) configfs_unregister_subsystem(example_subsys[i]); - } } module_init(configfs_example_init); diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index c79ec58..3ae9bc9 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -226,10 +226,6 @@ acl Enables POSIX Access Control Lists support. noacl This option disables POSIX Access Control List support. -reservation - -noreservation - bsddf (*) Make 'df' act like BSD. minixdf Make 'df' act like Minix. diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt index b9b4192..9c8fd61 100644 --- a/Documentation/filesystems/nfs/idmapper.txt +++ b/Documentation/filesystems/nfs/idmapper.txt @@ -47,8 +47,8 @@ request-key will find the first matching line and corresponding program. In this case, /some/other/program will handle all uid lookups and /usr/sbin/nfs.idmap will handle gid, user, and group lookups. -See <file:Documentation/keys-request-keys.txt> for more information about the -request-key function. +See <file:Documentation/security/keys-request-keys.txt> for more information +about the request-key function. ========= diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt index 9ed920a..7618a28 100644 --- a/Documentation/filesystems/ocfs2.txt +++ b/Documentation/filesystems/ocfs2.txt @@ -46,9 +46,15 @@ errors=panic Panic and halt the machine if an error occurs. intr (*) Allow signals to interrupt cluster operations. nointr Do not allow signals to interrupt cluster operations. +noatime Do not update access time. +relatime(*) Update atime if the previous atime is older than + mtime or ctime +strictatime Always update atime, but the minimum update interval + is specified by atime_quantum. atime_quantum=60(*) OCFS2 will not update atime unless this number of seconds has passed since the last update. - Set to zero to always update atime. + Set to zero to always update atime. This option need + work with strictatime. data=ordered (*) All data are forced directly out to the main file system prior to its metadata being committed to the journal. diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 60740e8..f481780 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -574,6 +574,12 @@ The contents of each smp_affinity file is the same by default: > cat /proc/irq/0/smp_affinity ffffffff +There is an alternate interface, smp_affinity_list which allows specifying +a cpu range instead of a bitmask: + + > cat /proc/irq/0/smp_affinity_list + 1024-1031 + The default_smp_affinity mask applies to all non-active IRQs, which are the IRQs which have not yet been allocated/activated, and hence which lack a /proc/irq/[0-9]* directory. @@ -583,12 +589,13 @@ reports itself as being attached. This hardware locality information does not include information about any possible driver locality preference. prof_cpu_mask specifies which CPUs are to be profiled by the system wide -profiler. Default value is ffffffff (all cpus). +profiler. Default value is ffffffff (all cpus if there are only 32 of them). The way IRQs are routed is handled by the IO-APIC, and it's Round Robin between all the CPUs which are allowed to handle it. As usual the kernel has more info than you and does a better job than you, so the defaults are the -best choice for almost everyone. +best choice for almost everyone. [Note this applies only to those IO-APIC's +that support "Round Robin" interrupt distribution.] There are three more important subdirectories in /proc: net, scsi, and sys. The general rule is that the contents, or even the existence of these diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt index d7b13b0..8e4fab6 100644 --- a/Documentation/filesystems/ubifs.txt +++ b/Documentation/filesystems/ubifs.txt @@ -115,28 +115,8 @@ ubi.mtd=0 root=ubi0:rootfs rootfstype=ubifs Module Parameters for Debugging =============================== -When UBIFS has been compiled with debugging enabled, there are 3 module +When UBIFS has been compiled with debugging enabled, there are 2 module parameters that are available to control aspects of testing and debugging. -The parameters are unsigned integers where each bit controls an option. -The parameters are: - -debug_msgs Selects which debug messages to display, as follows: - - Message Type Flag value - - General messages 1 - Journal messages 2 - Mount messages 4 - Commit messages 8 - LEB search messages 16 - Budgeting messages 32 - Garbage collection messages 64 - Tree Node Cache (TNC) messages 128 - LEB properties (lprops) messages 256 - Input/output messages 512 - Log messages 1024 - Scan messages 2048 - Recovery messages 4096 debug_chks Selects extra checks that UBIFS can do while running: @@ -154,11 +134,9 @@ debug_tsts Selects a mode of testing, as follows: Test mode Flag value - Force in-the-gaps method 2 Failure mode for recovery testing 4 -For example, set debug_msgs to 5 to display General messages and Mount -messages. +For example, set debug_chks to 3 to enable general and TNC checks. References diff --git a/Documentation/filesystems/xfs.txt b/Documentation/filesystems/xfs.txt index 7bff3e4..3fc0c31 100644 --- a/Documentation/filesystems/xfs.txt +++ b/Documentation/filesystems/xfs.txt @@ -39,6 +39,12 @@ When mounting an XFS filesystem, the following options are accepted. drive level write caching to be enabled, for devices that support write barriers. + discard + Issue command to let the block device reclaim space freed by the + filesystem. This is useful for SSD devices, thinly provisioned + LUNs and virtual machine images, but may have a performance + impact. This option is incompatible with the nodelaylog option. + dmapi Enable the DMAPI (Data Management API) event callouts. Use with the "mtpt" option. diff --git a/Documentation/hwmon/emc6w201 b/Documentation/hwmon/emc6w201 new file mode 100644 index 0000000..32f355a --- /dev/null +++ b/Documentation/hwmon/emc6w201 @@ -0,0 +1,42 @@ +Kernel driver emc6w201 +====================== + +Supported chips: + * SMSC EMC6W201 + Prefix: 'emc6w201' + Addresses scanned: I2C 0x2c, 0x2d, 0x2e + Datasheet: Not public + +Author: Jean Delvare <khali@linux-fr.org> + + +Description +----------- + +From the datasheet: + +"The EMC6W201 is an environmental monitoring device with automatic fan +control capability and enhanced system acoustics for noise suppression. +This ACPI compliant device provides hardware monitoring for up to six +voltages (including its own VCC) and five external thermal sensors, +measures the speed of up to five fans, and controls the speed of +multiple DC fans using three Pulse Width Modulator (PWM) outputs. Note +that it is possible to control more than three fans by connecting two +fans to one PWM output. The EMC6W201 will be available in a 36-pin +QFN package." + +The device is functionally close to the EMC6D100 series, but is +register-incompatible. + +The driver currently only supports the monitoring of the voltages, +temperatures and fan speeds. Limits can be changed. Alarms are not +supported, and neither is fan speed control. + + +Known Systems With EMC6W201 +--------------------------- + +The EMC6W201 is a rare device, only found on a few systems, made in +2005 and 2006. Known systems with this device: +* Dell Precision 670 workstation +* Gigabyte 2CEWH mainboard diff --git a/Documentation/hwmon/f71882fg b/Documentation/hwmon/f71882fg index df02245..84d2623 100644 --- a/Documentation/hwmon/f71882fg +++ b/Documentation/hwmon/f71882fg @@ -6,6 +6,10 @@ Supported chips: Prefix: 'f71808e' Addresses scanned: none, address read from Super I/O config space Datasheet: Not public + * Fintek F71808A + Prefix: 'f71808a' + Addresses scanned: none, address read from Super I/O config space + Datasheet: Not public * Fintek F71858FG Prefix: 'f71858fg' Addresses scanned: none, address read from Super I/O config space diff --git a/Documentation/hwmon/fam15h_power b/Documentation/hwmon/fam15h_power new file mode 100644 index 0000000..a92918e --- /dev/null +++ b/Documentation/hwmon/fam15h_power @@ -0,0 +1,37 @@ +Kernel driver fam15h_power +========================== + +Supported chips: +* AMD Family 15h Processors + + Prefix: 'fam15h_power' + Addresses scanned: PCI space + Datasheets: + BIOS and Kernel Developer's Guide (BKDG) For AMD Family 15h Processors + (not yet published) + +Author: Andreas Herrmann <andreas.herrmann3@amd.com> + +Description +----------- + +This driver permits reading of registers providing power information +of AMD Family 15h processors. + +For AMD Family 15h processors the following power values can be +calculated using different processor northbridge function registers: + +* BasePwrWatts: Specifies in watts the maximum amount of power + consumed by the processor for NB and logic external to the core. +* ProcessorPwrWatts: Specifies in watts the maximum amount of power + the processor can support. +* CurrPwrWatts: Specifies in watts the current amount of power being + consumed by the processor. + +This driver provides ProcessorPwrWatts and CurrPwrWatts: +* power1_crit (ProcessorPwrWatts) +* power1_input (CurrPwrWatts) + +On multi-node processors the calculated value is for the entire +package and not for a single node. Thus the driver creates sysfs +attributes only for internal node0 of a multi-node processor. diff --git a/Documentation/hwmon/k10temp b/Documentation/hwmon/k10temp index d2b56a4..0393c89 100644 --- a/Documentation/hwmon/k10temp +++ b/Documentation/hwmon/k10temp @@ -11,6 +11,7 @@ Supported chips: Socket S1G2: Athlon (X2), Sempron (X2), Turion X2 (Ultra) * AMD Family 12h processors: "Llano" * AMD Family 14h processors: "Brazos" (C/E/G-Series) +* AMD Family 15h processors: "Bulldozer" Prefix: 'k10temp' Addresses scanned: PCI space @@ -40,7 +41,7 @@ Description ----------- This driver permits reading of the internal temperature sensor of AMD -Family 10h/11h/12h/14h processors. +Family 10h/11h/12h/14h/15h processors. All these processors have a sensor, but on those for Socket F or AM2+, the sensor may return inconsistent values (erratum 319). The driver diff --git a/Documentation/hwmon/max6650 b/Documentation/hwmon/max6650 index c565650f..58d9644 100644 --- a/Documentation/hwmon/max6650 +++ b/Documentation/hwmon/max6650 @@ -2,9 +2,13 @@ Kernel driver max6650 ===================== Supported chips: - * Maxim 6650 / 6651 + * Maxim MAX6650 Prefix: 'max6650' - Addresses scanned: I2C 0x1b, 0x1f, 0x48, 0x4b + Addresses scanned: none + Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf + * Maxim MAX6651 + Prefix: 'max6651' + Addresses scanned: none Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf Authors: @@ -15,10 +19,10 @@ Authors: Description ----------- -This driver implements support for the Maxim 6650/6651 +This driver implements support for the Maxim MAX6650 and MAX6651. -The 2 devices are very similar, but the Maxim 6550 has a reduced feature -set, e.g. only one fan-input, instead of 4 for the 6651. +The 2 devices are very similar, but the MAX6550 has a reduced feature +set, e.g. only one fan-input, instead of 4 for the MAX6651. The driver is not able to distinguish between the 2 devices. @@ -36,6 +40,13 @@ fan1_div rw sets the speed range the inputs can handle. Legal values are 1, 2, 4, and 8. Use lower values for faster fans. +Usage notes +----------- + +This driver does not auto-detect devices. You will have to instantiate the +devices explicitly. Please see Documentation/i2c/instantiating-devices for +details. + Module parameters ----------------- diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801 index 6df6976..2871fd5 100644 --- a/Documentation/i2c/busses/i2c-i801 +++ b/Documentation/i2c/busses/i2c-i801 @@ -19,6 +19,7 @@ Supported adapters: * Intel 6 Series (PCH) * Intel Patsburg (PCH) * Intel DH89xxCC (PCH) + * Intel Panther Point (PCH) Datasheets: Publicly available at the Intel website On Intel Patsburg and later chipsets, both the normal host SMBus controller diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 5ebf5af..5aa5337 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -38,7 +38,7 @@ static struct i2c_driver foo_driver = { .name = "foo", }, - .id_table = foo_ids, + .id_table = foo_idtable, .probe = foo_probe, .remove = foo_remove, /* if device autodetection is needed: */ diff --git a/Documentation/input/elantech.txt b/Documentation/input/elantech.txt index 56941ae..db798af 100644 --- a/Documentation/input/elantech.txt +++ b/Documentation/input/elantech.txt @@ -34,7 +34,8 @@ Contents Currently the Linux Elantech touchpad driver is aware of two different hardware versions unimaginatively called version 1 and version 2. Version 1 is found in "older" laptops and uses 4 bytes per packet. Version 2 seems to -be introduced with the EeePC and uses 6 bytes per packet. +be introduced with the EeePC and uses 6 bytes per packet, and provides +additional features such as position of two fingers, and width of the touch. The driver tries to support both hardware versions and should be compatible with the Xorg Synaptics touchpad driver and its graphical configuration @@ -94,18 +95,44 @@ Currently the Linux Elantech touchpad driver provides two extra knobs under can check these bits and reject any packet that appears corrupted. Using this knob you can bypass that check. - It is not known yet whether hardware version 2 provides the same parity - bits. Hence checking is disabled by default. Currently even turning it on - will do nothing. - + Hardware version 2 does not provide the same parity bits. Only some basic + data consistency checking can be done. For now checking is disabled by + default. Currently even turning it on will do nothing. ///////////////////////////////////////////////////////////////////////////// +3. Differentiating hardware versions + ================================= + +To detect the hardware version, read the version number as param[0].param[1].param[2] + + 4 bytes version: (after the arrow is the name given in the Dell-provided driver) + 02.00.22 => EF013 + 02.06.00 => EF019 +In the wild, there appear to be more versions, such as 00.01.64, 01.00.21, +02.00.00, 02.00.04, 02.00.06. + + 6 bytes: + 02.00.30 => EF113 + 02.08.00 => EF023 + 02.08.XX => EF123 + 02.0B.00 => EF215 + 04.01.XX => Scroll_EF051 + 04.02.XX => EF051 +In the wild, there appear to be more versions, such as 04.03.01, 04.04.11. There +appears to be almost no difference, except for EF113, which does not report +pressure/width and has different data consistency checks. + +Probably all the versions with param[0] <= 01 can be considered as +4 bytes/firmware 1. The versions < 02.08.00, with the exception of 02.00.30, as +4 bytes/firmware 2. Everything >= 02.08.00 can be considered as 6 bytes. + +///////////////////////////////////////////////////////////////////////////// -3. Hardware version 1 +4. Hardware version 1 ================== -3.1 Registers +4.1 Registers ~~~~~~~~~ By echoing a hexadecimal value to a register it contents can be altered. @@ -168,7 +195,7 @@ For example: smart edge activation area width? -3.2 Native relative mode 4 byte packet format +4.2 Native relative mode 4 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ byte 0: @@ -226,9 +253,13 @@ byte 3: positive = down -3.3 Native absolute mode 4 byte packet format +4.3 Native absolute mode 4 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +EF013 and EF019 have a special behaviour (due to a bug in the firmware?), and +when 1 finger is touching, the first 2 position reports must be discarded. +This counting is reset whenever a different number of fingers is reported. + byte 0: firmware version 1.x: @@ -279,11 +310,11 @@ byte 3: ///////////////////////////////////////////////////////////////////////////// -4. Hardware version 2 +5. Hardware version 2 ================== -4.1 Registers +5.1 Registers ~~~~~~~~~ By echoing a hexadecimal value to a register it contents can be altered. @@ -316,16 +347,41 @@ For example: 0x7f = never i.e. tap again to release) -4.2 Native absolute mode 6 byte packet format +5.2 Native absolute mode 6 byte packet format ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -4.2.1 One finger touch +5.2.1 Parity checking and packet re-synchronization +There is no parity checking, however some consistency checks can be performed. + +For instance for EF113: + SA1= packet[0]; + A1 = packet[1]; + B1 = packet[2]; + SB1= packet[3]; + C1 = packet[4]; + D1 = packet[5]; + if( (((SA1 & 0x3C) != 0x3C) && ((SA1 & 0xC0) != 0x80)) || // check Byte 1 + (((SA1 & 0x0C) != 0x0C) && ((SA1 & 0xC0) == 0x80)) || // check Byte 1 (one finger pressed) + (((SA1 & 0xC0) != 0x80) && (( A1 & 0xF0) != 0x00)) || // check Byte 2 + (((SB1 & 0x3E) != 0x38) && ((SA1 & 0xC0) != 0x80)) || // check Byte 4 + (((SB1 & 0x0E) != 0x08) && ((SA1 & 0xC0) == 0x80)) || // check Byte 4 (one finger pressed) + (((SA1 & 0xC0) != 0x80) && (( C1 & 0xF0) != 0x00)) ) // check Byte 5 + // error detected + +For all the other ones, there are just a few constant bits: + if( ((packet[0] & 0x0C) != 0x04) || + ((packet[3] & 0x0f) != 0x02) ) + // error detected + + +In case an error is detected, all the packets are shifted by one (and packet[0] is discarded). + +5.2.1 One/Three finger touch ~~~~~~~~~~~~~~~~ byte 0: bit 7 6 5 4 3 2 1 0 - n1 n0 . . . . R L + n1 n0 w3 w2 . . R L L, R = 1 when Left, Right mouse button pressed n1..n0 = numbers of fingers on touchpad @@ -333,24 +389,40 @@ byte 0: byte 1: bit 7 6 5 4 3 2 1 0 - . . . . . x10 x9 x8 + p7 p6 p5 p4 . x10 x9 x8 byte 2: bit 7 6 5 4 3 2 1 0 - x7 x6 x5 x4 x4 x2 x1 x0 + x7 x6 x5 x4 x3 x2 x1 x0 x10..x0 = absolute x value (horizontal) byte 3: bit 7 6 5 4 3 2 1 0 - . . . . . . . . + n4 vf w1 w0 . . . b2 + + n4 = set if more than 3 fingers (only in 3 fingers mode) + vf = a kind of flag ? (only on EF123, 0 when finger is over one + of the buttons, 1 otherwise) + w3..w0 = width of the finger touch (not EF113) + b2 (on EF113 only, 0 otherwise), b2.R.L indicates one button pressed: + 0 = none + 1 = Left + 2 = Right + 3 = Middle (Left and Right) + 4 = Forward + 5 = Back + 6 = Another one + 7 = Another one byte 4: bit 7 6 5 4 3 2 1 0 - . . . . . . y9 y8 + p3 p1 p2 p0 . . y9 y8 + + p7..p0 = pressure (not EF113) byte 5: @@ -363,6 +435,11 @@ byte 5: 4.2.2 Two finger touch ~~~~~~~~~~~~~~~~ +Note that the two pairs of coordinates are not exactly the coordinates of the +two fingers, but only the pair of the lower-left and upper-right coordinates. +So the actual fingers might be situated on the other diagonal of the square +defined by these two points. + byte 0: bit 7 6 5 4 3 2 1 0 @@ -376,14 +453,14 @@ byte 1: bit 7 6 5 4 3 2 1 0 ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0 - ax8..ax0 = first finger absolute x value + ax8..ax0 = lower-left finger absolute x value byte 2: bit 7 6 5 4 3 2 1 0 ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 - ay8..ay0 = first finger absolute y value + ay8..ay0 = lower-left finger absolute y value byte 3: @@ -395,11 +472,11 @@ byte 4: bit 7 6 5 4 3 2 1 0 bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0 - bx8..bx0 = second finger absolute x value + bx8..bx0 = upper-right finger absolute x value byte 5: bit 7 6 5 4 3 2 1 0 by7 by8 by5 by4 by3 by2 by1 by0 - by8..by0 = second finger absolute y value + by8..by0 = upper-right finger absolute y value diff --git a/Documentation/input/rotary-encoder.txt b/Documentation/input/rotary-encoder.txt index 943e8f6..92e68bc 100644 --- a/Documentation/input/rotary-encoder.txt +++ b/Documentation/input/rotary-encoder.txt @@ -9,6 +9,9 @@ peripherals with two wires. The outputs are phase-shifted by 90 degrees and by triggering on falling and rising edges, the turn direction can be determined. +Some encoders have both outputs low in stable states, whereas others also have +a stable state with both outputs high (half-period mode). + The phase diagram of these two outputs look like this: _____ _____ _____ @@ -26,6 +29,8 @@ The phase diagram of these two outputs look like this: |<-------->| one step + |<-->| + one step (half-period mode) For more information, please see http://en.wikipedia.org/wiki/Rotary_encoder @@ -34,6 +39,13 @@ For more information, please see 1. Events / state machine ------------------------- +In half-period mode, state a) and c) above are used to determine the +rotational direction based on the last stable state. Events are reported in +states b) and d) given that the new stable state is different from the last +(i.e. the rotation was not reversed half-way). + +Otherwise, the following apply: + a) Rising edge on channel A, channel B in low state This state is used to recognize a clockwise turn @@ -96,6 +108,7 @@ static struct rotary_encoder_platform_data my_rotary_encoder_info = { .gpio_b = GPIO_ROTARY_B, .inverted_a = 0, .inverted_b = 0, + .half_period = false, }; static struct platform_device rotary_encoder_device = { diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 2d1ad12..3a46e36 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -304,6 +304,7 @@ Code Seq#(hex) Include File Comments 0xB0 all RATIO devices in development: <mailto:vgo@ratio.de> 0xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca> +0xB3 00 linux/mmc/ioctl.h 0xC0 00-0F linux/usb/iowarrior.h 0xCB 00-1F CBM serial IEC bus in development: <mailto:michael.klein@puffin.lb.shuttle.de> diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt index 7c2a89b..68e32bb 100644 --- a/Documentation/kbuild/kbuild.txt +++ b/Documentation/kbuild/kbuild.txt @@ -201,3 +201,16 @@ KBUILD_ENABLE_EXTRA_GCC_CHECKS -------------------------------------------------- If enabled over the make command line with "W=1", it turns on additional gcc -W... options for more extensive build-time checking. + +KBUILD_BUILD_TIMESTAMP +-------------------------------------------------- +Setting this to a date string overrides the timestamp used in the +UTS_VERSION definition (uname -v in the running kernel). The value has to +be a string that can be passed to date -d. The default value +is the output of the date command at one point during build. + +KBUILD_BUILD_USER, KBUILD_BUILD_HOST +-------------------------------------------------- +These two variables allow to override the user@host string displayed during +boot and in /proc/version. The default value is the output of the commands +whoami and host, respectively. diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt index b507d61..44e2649 100644 --- a/Documentation/kbuild/kconfig-language.txt +++ b/Documentation/kbuild/kconfig-language.txt @@ -113,6 +113,13 @@ applicable everywhere (see syntax). That will limit the usefulness but on the other hand avoid the illegal configurations all over. +- limiting menu display: "visible if" <expr> + This attribute is only applicable to menu blocks, if the condition is + false, the menu block is not displayed to the user (the symbols + contained there can still be selected by other symbols, though). It is + similar to a conditional "prompt" attribude for individual menu + entries. Default value of "visible" is true. + - numerical ranges: "range" <symbol> <symbol> ["if" <expr>] This allows to limit the range of possible input values for int and hex symbols. The user can only input a value which is larger than @@ -303,7 +310,8 @@ menu: "endmenu" This defines a menu block, see "Menu structure" above for more -information. The only possible options are dependencies. +information. The only possible options are dependencies and "visible" +attributes. if: @@ -381,3 +389,25 @@ config FOO limits FOO to module (=m) or disabled (=n). +Kconfig symbol existence +~~~~~~~~~~~~~~~~~~~~~~~~ +The following two methods produce the same kconfig symbol dependencies +but differ greatly in kconfig symbol existence (production) in the +generated config file. + +case 1: + +config FOO + tristate "about foo" + depends on BAR + +vs. case 2: + +if BAR +config FOO + tristate "about foo" +endif + +In case 1, the symbol FOO will always exist in the config file (given +no other dependencies). In case 2, the symbol FOO will only exist in +the config file if BAR is enabled. diff --git a/Documentation/kbuild/kconfig.txt b/Documentation/kbuild/kconfig.txt index cca46b1..c313d71 100644 --- a/Documentation/kbuild/kconfig.txt +++ b/Documentation/kbuild/kconfig.txt @@ -48,11 +48,6 @@ KCONFIG_OVERWRITECONFIG If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not break symlinks when .config is a symlink to somewhere else. -KCONFIG_NOTIMESTAMP --------------------------------------------------- -If this environment variable exists and is non-null, the timestamp line -in generated .config files is omitted. - ______________________________________________________________________ Environment variables for '{allyes/allmod/allno/rand}config' diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 5d145bb..47435e5 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -40,11 +40,13 @@ This document describes the Linux kernel Makefiles. --- 6.6 Commands useful for building a boot image --- 6.7 Custom kbuild commands --- 6.8 Preprocessing linker scripts + --- 6.9 Generic header files === 7 Kbuild syntax for exported headers --- 7.1 header-y --- 7.2 objhdr-y --- 7.3 destination-y + --- 7.4 generic-y === 8 Kbuild Variables === 9 Makefile language @@ -499,6 +501,18 @@ more details, with real examples. gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used. Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options + cc-disable-warning + cc-disable-warning checks if gcc supports a given warning and returns + the commandline switch to disable it. This special function is needed, + because gcc 4.4 and later accept any unknown -Wno-* option and only + warn about it if there is another warning in the source file. + + Example: + KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) + + In the above example, -Wno-unused-but-set-variable will be added to + KBUILD_CFLAGS only if gcc really accepts it. + cc-version cc-version returns a numerical version of the $(CC) compiler version. The format is <major><minor> where both are two digits. So for example @@ -955,6 +969,11 @@ When kbuild executes, the following steps are followed (roughly): used when linking modules. This is often a linker script. From commandline LDFLAGS_MODULE shall be used (see kbuild.txt). + KBUILD_ARFLAGS Options for $(AR) when creating archives + + $(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic + mode) if this option is supported by $(AR). + --- 6.2 Add prerequisites to archprepare: The archprepare: rule is used to list prerequisites that need to be @@ -1209,6 +1228,14 @@ When kbuild executes, the following steps are followed (roughly): The kbuild infrastructure for *lds file are used in several architecture-specific files. +--- 6.9 Generic header files + + The directory include/asm-generic contains the header files + that may be shared between individual architectures. + The recommended approach how to use a generic header file is + to list the file in the Kbuild file. + See "7.4 generic-y" for further info on syntax etc. + === 7 Kbuild syntax for exported headers The kernel include a set of headers that is exported to userspace. @@ -1265,6 +1292,32 @@ See subsequent chapter for the syntax of the Kbuild file. In the example above all exported headers in the Kbuild file will be located in the directory "include/linux" when exported. + --- 7.4 generic-y + + If an architecture uses a verbatim copy of a header from + include/asm-generic then this is listed in the file + arch/$(ARCH)/include/asm/Kbuild like this: + + Example: + #arch/x86/include/asm/Kbuild + generic-y += termios.h + generic-y += rtc.h + + During the prepare phase of the build a wrapper include + file is generated in the directory: + + arch/$(ARCH)/include/generated/asm + + When a header is exported where the architecture uses + the generic header a similar wrapper is generated as part + of the set of exported headers in the directory: + + usr/include/asm + + The generated wrapper will in both cases look like the following: + + Example: termios.h + #include <asm-generic/termios.h> === 8 Kbuild Variables diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 7c6624e..5438a2d 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1777,9 +1777,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nosoftlockup [KNL] Disable the soft-lockup detector. - noswapaccount [KNL] Disable accounting of swap in memory resource - controller. (See Documentation/cgroups/memory.txt) - nosync [HW,M68K] Disables sync negotiation for all devices. notsc [BUGS=X86-32] Disable Time Stamp Counter diff --git a/Documentation/lockstat.txt b/Documentation/lockstat.txt index 65f4c79..9c0a80d 100644 --- a/Documentation/lockstat.txt +++ b/Documentation/lockstat.txt @@ -136,7 +136,7 @@ View the top contending locks: dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24 &inode->i_mutex: 161 286 18446744073709 62882.54 1244614.55 3653 20598 18446744073709 62318.60 1693822.74 &zone->lru_lock: 94 94 0.53 7.33 92.10 4366 32690 0.29 59.81 16350.06 - &inode->i_data.i_mmap_lock: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44 + &inode->i_data.i_mmap_mutex: 79 79 0.40 3.77 53.03 11779 87755 0.28 116.93 29898.44 &q->__queue_lock: 48 50 0.52 31.62 86.31 774 13131 0.17 113.08 12277.52 &rq->rq_lock_key: 43 47 0.74 68.50 170.63 3706 33929 0.22 107.99 17460.62 &rq->rq_lock_key#2: 39 46 0.75 6.68 49.03 2979 32292 0.17 125.17 17137.63 diff --git a/Documentation/mmc/00-INDEX b/Documentation/mmc/00-INDEX index fca586f..93dd7a7 100644 --- a/Documentation/mmc/00-INDEX +++ b/Documentation/mmc/00-INDEX @@ -2,3 +2,5 @@ - this file mmc-dev-attrs.txt - info on SD and MMC device attributes +mmc-dev-parts.txt + - info on SD and MMC device partitions diff --git a/Documentation/mmc/mmc-dev-attrs.txt b/Documentation/mmc/mmc-dev-attrs.txt index ff2bd68..8898a95 100644 --- a/Documentation/mmc/mmc-dev-attrs.txt +++ b/Documentation/mmc/mmc-dev-attrs.txt @@ -1,3 +1,13 @@ +SD and MMC Block Device Attributes +================================== + +These attributes are defined for the block devices associated with the +SD or MMC device. + +The following attributes are read/write. + + force_ro Enforce read-only access even if write protect switch is off. + SD and MMC Device Attributes ============================ diff --git a/Documentation/mmc/mmc-dev-parts.txt b/Documentation/mmc/mmc-dev-parts.txt new file mode 100644 index 0000000..2db28b8 --- /dev/null +++ b/Documentation/mmc/mmc-dev-parts.txt @@ -0,0 +1,27 @@ +SD and MMC Device Partitions +============================ + +Device partitions are additional logical block devices present on the +SD/MMC device. + +As of this writing, MMC boot partitions as supported and exposed as +/dev/mmcblkXboot0 and /dev/mmcblkXboot1, where X is the index of the +parent /dev/mmcblkX. + +MMC Boot Partitions +=================== + +Read and write access is provided to the two MMC boot partitions. Due to +the sensitive nature of the boot partition contents, which often store +a bootloader or bootloader configuration tables crucial to booting the +platform, write access is disabled by default to reduce the chance of +accidental bricking. + +To enable write access to /dev/mmcblkXbootY, disable the forced read-only +access with: + +echo 0 > /sys/block/mmcblkXbootY/force_ro + +To re-enable read-only access: + +echo 1 > /sys/block/mmcblkXbootY/force_ro diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index 1f45bd8..675612f 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -770,8 +770,17 @@ resend_igmp a failover event. One membership report is issued immediately after the failover, subsequent packets are sent in each 200ms interval. - The valid range is 0 - 255; the default value is 1. This option - was added for bonding version 3.7.0. + The valid range is 0 - 255; the default value is 1. A value of 0 + prevents the IGMP membership report from being issued in response + to the failover event. + + This option is useful for bonding modes balance-rr (0), active-backup + (1), balance-tlb (5) and balance-alb (6), in which a failover can + switch the IGMP traffic from one slave to another. Therefore a fresh + IGMP report must be issued to cause the switch to forward the incoming + IGMP traffic over the newly selected slave. + + This option was added for bonding version 3.7.0. 3. Configuring Bonding Devices ============================== diff --git a/Documentation/networking/dns_resolver.txt b/Documentation/networking/dns_resolver.txt index 04ca0632..7f531ad 100644 --- a/Documentation/networking/dns_resolver.txt +++ b/Documentation/networking/dns_resolver.txt @@ -139,8 +139,8 @@ the key will be discarded and recreated when the data it holds has expired. dns_query() returns a copy of the value attached to the key, or an error if that is indicated instead. -See <file:Documentation/keys-request-key.txt> for further information about -request-key function. +See <file:Documentation/security/keys-request-key.txt> for further +information about request-key function. ========= diff --git a/Documentation/power/regulator/machine.txt b/Documentation/power/regulator/machine.txt index bdec39b..b42419b 100644 --- a/Documentation/power/regulator/machine.txt +++ b/Documentation/power/regulator/machine.txt @@ -53,11 +53,11 @@ static struct regulator_init_data regulator1_data = { Regulator-1 supplies power to Regulator-2. This relationship must be registered with the core so that Regulator-1 is also enabled when Consumer A enables its -supply (Regulator-2). The supply regulator is set by the supply_regulator_dev +supply (Regulator-2). The supply regulator is set by the supply_regulator field below:- static struct regulator_init_data regulator2_data = { - .supply_regulator_dev = &platform_regulator1_device.dev, + .supply_regulator = "regulator_name", .constraints = { .min_uV = 1800000, .max_uV = 2000000, diff --git a/Documentation/ptp/ptp.txt b/Documentation/ptp/ptp.txt new file mode 100644 index 0000000..ae8fef8 --- /dev/null +++ b/Documentation/ptp/ptp.txt @@ -0,0 +1,89 @@ + +* PTP hardware clock infrastructure for Linux + + This patch set introduces support for IEEE 1588 PTP clocks in + Linux. Together with the SO_TIMESTAMPING socket options, this + presents a standardized method for developing PTP user space + programs, synchronizing Linux with external clocks, and using the + ancillary features of PTP hardware clocks. + + A new class driver exports a kernel interface for specific clock + drivers and a user space interface. The infrastructure supports a + complete set of PTP hardware clock functionality. + + + Basic clock operations + - Set time + - Get time + - Shift the clock by a given offset atomically + - Adjust clock frequency + + + Ancillary clock features + - One short or periodic alarms, with signal delivery to user program + - Time stamp external events + - Period output signals configurable from user space + - Synchronization of the Linux system time via the PPS subsystem + +** PTP hardware clock kernel API + + A PTP clock driver registers itself with the class driver. The + class driver handles all of the dealings with user space. The + author of a clock driver need only implement the details of + programming the clock hardware. The clock driver notifies the class + driver of asynchronous events (alarms and external time stamps) via + a simple message passing interface. + + The class driver supports multiple PTP clock drivers. In normal use + cases, only one PTP clock is needed. However, for testing and + development, it can be useful to have more than one clock in a + single system, in order to allow performance comparisons. + +** PTP hardware clock user space API + + The class driver also creates a character device for each + registered clock. User space can use an open file descriptor from + the character device as a POSIX clock id and may call + clock_gettime, clock_settime, and clock_adjtime. These calls + implement the basic clock operations. + + User space programs may control the clock using standardized + ioctls. A program may query, enable, configure, and disable the + ancillary clock features. User space can receive time stamped + events via blocking read() and poll(). One shot and periodic + signals may be configured via the POSIX timer_settime() system + call. + +** Writing clock drivers + + Clock drivers include include/linux/ptp_clock_kernel.h and register + themselves by presenting a 'struct ptp_clock_info' to the + registration method. Clock drivers must implement all of the + functions in the interface. If a clock does not offer a particular + ancillary feature, then the driver should just return -EOPNOTSUPP + from those functions. + + Drivers must ensure that all of the methods in interface are + reentrant. Since most hardware implementations treat the time value + as a 64 bit integer accessed as two 32 bit registers, drivers + should use spin_lock_irqsave/spin_unlock_irqrestore to protect + against concurrent access. This locking cannot be accomplished in + class driver, since the lock may also be needed by the clock + driver's interrupt service routine. + +** Supported hardware + + + Freescale eTSEC gianfar + - 2 Time stamp external triggers, programmable polarity (opt. interrupt) + - 2 Alarm registers (optional interrupt) + - 3 Periodic signals (optional interrupt) + + + National DP83640 + - 6 GPIOs programmable as inputs or outputs + - 6 GPIOs with dedicated functions (LED/JTAG/clock) can also be + used as general inputs or outputs + - GPIO inputs can time stamp external triggers + - GPIO outputs can produce periodic signals + - 1 interrupt pin + + + Intel IXP465 + - Auxiliary Slave/Master Mode Snapshot (optional interrupt) + - Target Time (optional interrupt) diff --git a/Documentation/ptp/testptp.c b/Documentation/ptp/testptp.c new file mode 100644 index 0000000..f59ded0 --- /dev/null +++ b/Documentation/ptp/testptp.c @@ -0,0 +1,381 @@ +/* + * PTP 1588 clock support - User space test program + * + * Copyright (C) 2010 OMICRON electronics GmbH + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include <errno.h> +#include <fcntl.h> +#include <math.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <sys/timex.h> +#include <sys/types.h> +#include <time.h> +#include <unistd.h> + +#include <linux/ptp_clock.h> + +#define DEVICE "/dev/ptp0" + +#ifndef ADJ_SETOFFSET +#define ADJ_SETOFFSET 0x0100 +#endif + +#ifndef CLOCK_INVALID +#define CLOCK_INVALID -1 +#endif + +/* When glibc offers the syscall, this will go away. */ +#include <sys/syscall.h> +static int clock_adjtime(clockid_t id, struct timex *tx) +{ + return syscall(__NR_clock_adjtime, id, tx); +} + +static clockid_t get_clockid(int fd) +{ +#define CLOCKFD 3 +#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD) + + return FD_TO_CLOCKID(fd); +} + +static void handle_alarm(int s) +{ + printf("received signal %d\n", s); +} + +static int install_handler(int signum, void (*handler)(int)) +{ + struct sigaction action; + sigset_t mask; + + /* Unblock the signal. */ + sigemptyset(&mask); + sigaddset(&mask, signum); + sigprocmask(SIG_UNBLOCK, &mask, NULL); + + /* Install the signal handler. */ + action.sa_handler = handler; + action.sa_flags = 0; + sigemptyset(&action.sa_mask); + sigaction(signum, &action, NULL); + + return 0; +} + +static long ppb_to_scaled_ppm(int ppb) +{ + /* + * The 'freq' field in the 'struct timex' is in parts per + * million, but with a 16 bit binary fractional field. + * Instead of calculating either one of + * + * scaled_ppm = (ppb / 1000) << 16 [1] + * scaled_ppm = (ppb << 16) / 1000 [2] + * + * we simply use double precision math, in order to avoid the + * truncation in [1] and the possible overflow in [2]. + */ + return (long) (ppb * 65.536); +} + +static void usage(char *progname) +{ + fprintf(stderr, + "usage: %s [options]\n" + " -a val request a one-shot alarm after 'val' seconds\n" + " -A val request a periodic alarm every 'val' seconds\n" + " -c query the ptp clock's capabilities\n" + " -d name device to open\n" + " -e val read 'val' external time stamp events\n" + " -f val adjust the ptp clock frequency by 'val' ppb\n" + " -g get the ptp clock time\n" + " -h prints this message\n" + " -p val enable output with a period of 'val' nanoseconds\n" + " -P val enable or disable (val=1|0) the system clock PPS\n" + " -s set the ptp clock time from the system time\n" + " -S set the system time from the ptp clock time\n" + " -t val shift the ptp clock time by 'val' seconds\n", + progname); +} + +int main(int argc, char *argv[]) +{ + struct ptp_clock_caps caps; + struct ptp_extts_event event; + struct ptp_extts_request extts_request; + struct ptp_perout_request perout_request; + struct timespec ts; + struct timex tx; + + static timer_t timerid; + struct itimerspec timeout; + struct sigevent sigevent; + + char *progname; + int c, cnt, fd; + + char *device = DEVICE; + clockid_t clkid; + int adjfreq = 0x7fffffff; + int adjtime = 0; + int capabilities = 0; + int extts = 0; + int gettime = 0; + int oneshot = 0; + int periodic = 0; + int perout = -1; + int pps = -1; + int settime = 0; + + progname = strrchr(argv[0], '/'); + progname = progname ? 1+progname : argv[0]; + while (EOF != (c = getopt(argc, argv, "a:A:cd:e:f:ghp:P:sSt:v"))) { + switch (c) { + case 'a': + oneshot = atoi(optarg); + break; + case 'A': + periodic = atoi(optarg); + break; + case 'c': + capabilities = 1; + break; + case 'd': + device = optarg; + break; + case 'e': + extts = atoi(optarg); + break; + case 'f': + adjfreq = atoi(optarg); + break; + case 'g': + gettime = 1; + break; + case 'p': + perout = atoi(optarg); + break; + case 'P': + pps = atoi(optarg); + break; + case 's': + settime = 1; + break; + case 'S': + settime = 2; + break; + case 't': + adjtime = atoi(optarg); + break; + case 'h': + usage(progname); + return 0; + case '?': + default: + usage(progname); + return -1; + } + } + + fd = open(device, O_RDWR); + if (fd < 0) { + fprintf(stderr, "opening %s: %s\n", device, strerror(errno)); + return -1; + } + + clkid = get_clockid(fd); + if (CLOCK_INVALID == clkid) { + fprintf(stderr, "failed to read clock id\n"); + return -1; + } + + if (capabilities) { + if (ioctl(fd, PTP_CLOCK_GETCAPS, &caps)) { + perror("PTP_CLOCK_GETCAPS"); + } else { + printf("capabilities:\n" + " %d maximum frequency adjustment (ppb)\n" + " %d programmable alarms\n" + " %d external time stamp channels\n" + " %d programmable periodic signals\n" + " %d pulse per second\n", + caps.max_adj, + caps.n_alarm, + caps.n_ext_ts, + caps.n_per_out, + caps.pps); + } + } + + if (0x7fffffff != adjfreq) { + memset(&tx, 0, sizeof(tx)); + tx.modes = ADJ_FREQUENCY; + tx.freq = ppb_to_scaled_ppm(adjfreq); + if (clock_adjtime(clkid, &tx)) { + perror("clock_adjtime"); + } else { + puts("frequency adjustment okay"); + } + } + + if (adjtime) { + memset(&tx, 0, sizeof(tx)); + tx.modes = ADJ_SETOFFSET; + tx.time.tv_sec = adjtime; + tx.time.tv_usec = 0; + if (clock_adjtime(clkid, &tx) < 0) { + perror("clock_adjtime"); + } else { + puts("time shift okay"); + } + } + + if (gettime) { + if (clock_gettime(clkid, &ts)) { + perror("clock_gettime"); + } else { + printf("clock time: %ld.%09ld or %s", + ts.tv_sec, ts.tv_nsec, ctime(&ts.tv_sec)); + } + } + + if (settime == 1) { + clock_gettime(CLOCK_REALTIME, &ts); + if (clock_settime(clkid, &ts)) { + perror("clock_settime"); + } else { + puts("set time okay"); + } + } + + if (settime == 2) { + clock_gettime(clkid, &ts); + if (clock_settime(CLOCK_REALTIME, &ts)) { + perror("clock_settime"); + } else { + puts("set time okay"); + } + } + + if (extts) { + memset(&extts_request, 0, sizeof(extts_request)); + extts_request.index = 0; + extts_request.flags = PTP_ENABLE_FEATURE; + if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) { + perror("PTP_EXTTS_REQUEST"); + extts = 0; + } else { + puts("external time stamp request okay"); + } + for (; extts; extts--) { + cnt = read(fd, &event, sizeof(event)); + if (cnt != sizeof(event)) { + perror("read"); + break; + } + printf("event index %u at %lld.%09u\n", event.index, + event.t.sec, event.t.nsec); + fflush(stdout); + } + /* Disable the feature again. */ + extts_request.flags = 0; + if (ioctl(fd, PTP_EXTTS_REQUEST, &extts_request)) { + perror("PTP_EXTTS_REQUEST"); + } + } + + if (oneshot) { + install_handler(SIGALRM, handle_alarm); + /* Create a timer. */ + sigevent.sigev_notify = SIGEV_SIGNAL; + sigevent.sigev_signo = SIGALRM; + if (timer_create(clkid, &sigevent, &timerid)) { + perror("timer_create"); + return -1; + } + /* Start the timer. */ + memset(&timeout, 0, sizeof(timeout)); + timeout.it_value.tv_sec = oneshot; + if (timer_settime(timerid, 0, &timeout, NULL)) { + perror("timer_settime"); + return -1; + } + pause(); + timer_delete(timerid); + } + + if (periodic) { + install_handler(SIGALRM, handle_alarm); + /* Create a timer. */ + sigevent.sigev_notify = SIGEV_SIGNAL; + sigevent.sigev_signo = SIGALRM; + if (timer_create(clkid, &sigevent, &timerid)) { + perror("timer_create"); + return -1; + } + /* Start the timer. */ + memset(&timeout, 0, sizeof(timeout)); + timeout.it_interval.tv_sec = periodic; + timeout.it_value.tv_sec = periodic; + if (timer_settime(timerid, 0, &timeout, NULL)) { + perror("timer_settime"); + return -1; + } + while (1) { + pause(); + } + timer_delete(timerid); + } + + if (perout >= 0) { + if (clock_gettime(clkid, &ts)) { + perror("clock_gettime"); + return -1; + } + memset(&perout_request, 0, sizeof(perout_request)); + perout_request.index = 0; + perout_request.start.sec = ts.tv_sec + 2; + perout_request.start.nsec = 0; + perout_request.period.sec = 0; + perout_request.period.nsec = perout; + if (ioctl(fd, PTP_PEROUT_REQUEST, &perout_request)) { + perror("PTP_PEROUT_REQUEST"); + } else { + puts("periodic output request okay"); + } + } + + if (pps != -1) { + int enable = pps ? 1 : 0; + if (ioctl(fd, PTP_ENABLE_PPS, enable)) { + perror("PTP_ENABLE_PPS"); + } else { + puts("pps for system time request okay"); + } + } + + close(fd); + return 0; +} diff --git a/Documentation/ptp/testptp.mk b/Documentation/ptp/testptp.mk new file mode 100644 index 0000000..4ef2d97 --- /dev/null +++ b/Documentation/ptp/testptp.mk @@ -0,0 +1,33 @@ +# PTP 1588 clock support - User space test program +# +# Copyright (C) 2010 OMICRON electronics GmbH +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + +CC = $(CROSS_COMPILE)gcc +INC = -I$(KBUILD_OUTPUT)/usr/include +CFLAGS = -Wall $(INC) +LDLIBS = -lrt +PROGS = testptp + +all: $(PROGS) + +testptp: testptp.o + +clean: + rm -f testptp.o + +distclean: clean + rm -f $(PROGS) diff --git a/Documentation/security/00-INDEX b/Documentation/security/00-INDEX new file mode 100644 index 0000000..19bc494 --- /dev/null +++ b/Documentation/security/00-INDEX @@ -0,0 +1,18 @@ +00-INDEX + - this file. +SELinux.txt + - how to get started with the SELinux security enhancement. +Smack.txt + - documentation on the Smack Linux Security Module. +apparmor.txt + - documentation on the AppArmor security extension. +credentials.txt + - documentation about credentials in Linux. +keys-request-key.txt + - description of the kernel key request service. +keys-trusted-encrypted.txt + - info on the Trusted and Encrypted keys in the kernel key ring service. +keys.txt + - description of the kernel key retention service. +tomoyo.txt + - documentation on the TOMOYO Linux Security Module. diff --git a/Documentation/SELinux.txt b/Documentation/security/SELinux.txt index 07eae00f..07eae00f 100644 --- a/Documentation/SELinux.txt +++ b/Documentation/security/SELinux.txt diff --git a/Documentation/Smack.txt b/Documentation/security/Smack.txt index e9dab41..e9dab41 100644 --- a/Documentation/Smack.txt +++ b/Documentation/security/Smack.txt diff --git a/Documentation/apparmor.txt b/Documentation/security/apparmor.txt index 93c1fd7..93c1fd7 100644 --- a/Documentation/apparmor.txt +++ b/Documentation/security/apparmor.txt diff --git a/Documentation/credentials.txt b/Documentation/security/credentials.txt index 995baf3..fc0366c 100644 --- a/Documentation/credentials.txt +++ b/Documentation/security/credentials.txt @@ -216,7 +216,7 @@ The Linux kernel supports the following types of credentials: When a process accesses a key, if not already present, it will normally be cached on one of these keyrings for future accesses to find. - For more information on using keys, see Documentation/keys.txt. + For more information on using keys, see Documentation/security/keys.txt. (5) LSM diff --git a/Documentation/keys-request-key.txt b/Documentation/security/keys-request-key.txt index 69686ad..51987bf 100644 --- a/Documentation/keys-request-key.txt +++ b/Documentation/security/keys-request-key.txt @@ -3,8 +3,8 @@ =================== The key request service is part of the key retention service (refer to -Documentation/keys.txt). This document explains more fully how the requesting -algorithm works. +Documentation/security/keys.txt). This document explains more fully how +the requesting algorithm works. The process starts by either the kernel requesting a service by calling request_key*(): diff --git a/Documentation/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt index 8fb79bc..8fb79bc 100644 --- a/Documentation/keys-trusted-encrypted.txt +++ b/Documentation/security/keys-trusted-encrypted.txt diff --git a/Documentation/keys.txt b/Documentation/security/keys.txt index 6523a9e..4d75931 100644 --- a/Documentation/keys.txt +++ b/Documentation/security/keys.txt @@ -434,7 +434,7 @@ The main syscalls are: /sbin/request-key will be invoked in an attempt to obtain a key. The callout_info string will be passed as an argument to the program. - See also Documentation/keys-request-key.txt. + See also Documentation/security/keys-request-key.txt. The keyctl syscall functions are: @@ -864,7 +864,7 @@ payload contents" for more information. If successful, the key will have been attached to the default keyring for implicitly obtained request-key keys, as set by KEYCTL_SET_REQKEY_KEYRING. - See also Documentation/keys-request-key.txt. + See also Documentation/security/keys-request-key.txt. (*) To search for a key, passing auxiliary data to the upcaller, call: diff --git a/Documentation/tomoyo.txt b/Documentation/security/tomoyo.txt index 200a2d3..200a2d3 100644 --- a/Documentation/tomoyo.txt +++ b/Documentation/security/tomoyo.txt diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 36f0075..5e7cb39 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -161,7 +161,8 @@ core_pattern is used to specify a core dumpfile pattern name. %s signal number %t UNIX time of dump %h hostname - %e executable filename + %e executable filename (may be shortened) + %E executable path %<OTHER> both are dropped . If the first character of the pattern is a '|', the kernel will treat the rest of the pattern as a command to run. The core dump will be diff --git a/Documentation/virtual/uml/UserModeLinux-HOWTO.txt b/Documentation/virtual/uml/UserModeLinux-HOWTO.txt index 9b7e190..5d0fc8b 100644 --- a/Documentation/virtual/uml/UserModeLinux-HOWTO.txt +++ b/Documentation/virtual/uml/UserModeLinux-HOWTO.txt @@ -1182,6 +1182,16 @@ forge.net/> and explains these in detail, as well as some other issues. + There is also a related point-to-point only "ucast" transport. + This is useful when your network does not support multicast, and + all network connections are simple point to point links. + + The full set of command line options for this transport are + + + ethn=ucast,ethernet address,remote address,listen port,remote port + + 66..66.. TTUUNN//TTAAPP wwiitthh tthhee uummll__nneett hheellppeerr diff --git a/Documentation/vm/cleancache.txt b/Documentation/vm/cleancache.txt new file mode 100644 index 0000000..36c367c --- /dev/null +++ b/Documentation/vm/cleancache.txt @@ -0,0 +1,278 @@ +MOTIVATION + +Cleancache is a new optional feature provided by the VFS layer that +potentially dramatically increases page cache effectiveness for +many workloads in many environments at a negligible cost. + +Cleancache can be thought of as a page-granularity victim cache for clean +pages that the kernel's pageframe replacement algorithm (PFRA) would like +to keep around, but can't since there isn't enough memory. So when the +PFRA "evicts" a page, it first attempts to use cleancache code to +put the data contained in that page into "transcendent memory", memory +that is not directly accessible or addressable by the kernel and is +of unknown and possibly time-varying size. + +Later, when a cleancache-enabled filesystem wishes to access a page +in a file on disk, it first checks cleancache to see if it already +contains it; if it does, the page of data is copied into the kernel +and a disk access is avoided. + +Transcendent memory "drivers" for cleancache are currently implemented +in Xen (using hypervisor memory) and zcache (using in-kernel compressed +memory) and other implementations are in development. + +FAQs are included below. + +IMPLEMENTATION OVERVIEW + +A cleancache "backend" that provides transcendent memory registers itself +to the kernel's cleancache "frontend" by calling cleancache_register_ops, +passing a pointer to a cleancache_ops structure with funcs set appropriately. +Note that cleancache_register_ops returns the previous settings so that +chaining can be performed if desired. The functions provided must conform to +certain semantics as follows: + +Most important, cleancache is "ephemeral". Pages which are copied into +cleancache have an indefinite lifetime which is completely unknowable +by the kernel and so may or may not still be in cleancache at any later time. +Thus, as its name implies, cleancache is not suitable for dirty pages. +Cleancache has complete discretion over what pages to preserve and what +pages to discard and when. + +Mounting a cleancache-enabled filesystem should call "init_fs" to obtain a +pool id which, if positive, must be saved in the filesystem's superblock; +a negative return value indicates failure. A "put_page" will copy a +(presumably about-to-be-evicted) page into cleancache and associate it with +the pool id, a file key, and a page index into the file. (The combination +of a pool id, a file key, and an index is sometimes called a "handle".) +A "get_page" will copy the page, if found, from cleancache into kernel memory. +A "flush_page" will ensure the page no longer is present in cleancache; +a "flush_inode" will flush all pages associated with the specified file; +and, when a filesystem is unmounted, a "flush_fs" will flush all pages in +all files specified by the given pool id and also surrender the pool id. + +An "init_shared_fs", like init_fs, obtains a pool id but tells cleancache +to treat the pool as shared using a 128-bit UUID as a key. On systems +that may run multiple kernels (such as hard partitioned or virtualized +systems) that may share a clustered filesystem, and where cleancache +may be shared among those kernels, calls to init_shared_fs that specify the +same UUID will receive the same pool id, thus allowing the pages to +be shared. Note that any security requirements must be imposed outside +of the kernel (e.g. by "tools" that control cleancache). Or a +cleancache implementation can simply disable shared_init by always +returning a negative value. + +If a get_page is successful on a non-shared pool, the page is flushed (thus +making cleancache an "exclusive" cache). On a shared pool, the page +is NOT flushed on a successful get_page so that it remains accessible to +other sharers. The kernel is responsible for ensuring coherency between +cleancache (shared or not), the page cache, and the filesystem, using +cleancache flush operations as required. + +Note that cleancache must enforce put-put-get coherency and get-get +coherency. For the former, if two puts are made to the same handle but +with different data, say AAA by the first put and BBB by the second, a +subsequent get can never return the stale data (AAA). For get-get coherency, +if a get for a given handle fails, subsequent gets for that handle will +never succeed unless preceded by a successful put with that handle. + +Last, cleancache provides no SMP serialization guarantees; if two +different Linux threads are simultaneously putting and flushing a page +with the same handle, the results are indeterminate. Callers must +lock the page to ensure serial behavior. + +CLEANCACHE PERFORMANCE METRICS + +Cleancache monitoring is done by sysfs files in the +/sys/kernel/mm/cleancache directory. The effectiveness of cleancache +can be measured (across all filesystems) with: + +succ_gets - number of gets that were successful +failed_gets - number of gets that failed +puts - number of puts attempted (all "succeed") +flushes - number of flushes attempted + +A backend implementatation may provide additional metrics. + +FAQ + +1) Where's the value? (Andrew Morton) + +Cleancache provides a significant performance benefit to many workloads +in many environments with negligible overhead by improving the +effectiveness of the pagecache. Clean pagecache pages are +saved in transcendent memory (RAM that is otherwise not directly +addressable to the kernel); fetching those pages later avoids "refaults" +and thus disk reads. + +Cleancache (and its sister code "frontswap") provide interfaces for +this transcendent memory (aka "tmem"), which conceptually lies between +fast kernel-directly-addressable RAM and slower DMA/asynchronous devices. +Disallowing direct kernel or userland reads/writes to tmem +is ideal when data is transformed to a different form and size (such +as with compression) or secretly moved (as might be useful for write- +balancing for some RAM-like devices). Evicted page-cache pages (and +swap pages) are a great use for this kind of slower-than-RAM-but-much- +faster-than-disk transcendent memory, and the cleancache (and frontswap) +"page-object-oriented" specification provides a nice way to read and +write -- and indirectly "name" -- the pages. + +In the virtual case, the whole point of virtualization is to statistically +multiplex physical resources across the varying demands of multiple +virtual machines. This is really hard to do with RAM and efforts to +do it well with no kernel change have essentially failed (except in some +well-publicized special-case workloads). Cleancache -- and frontswap -- +with a fairly small impact on the kernel, provide a huge amount +of flexibility for more dynamic, flexible RAM multiplexing. +Specifically, the Xen Transcendent Memory backend allows otherwise +"fallow" hypervisor-owned RAM to not only be "time-shared" between multiple +virtual machines, but the pages can be compressed and deduplicated to +optimize RAM utilization. And when guest OS's are induced to surrender +underutilized RAM (e.g. with "self-ballooning"), page cache pages +are the first to go, and cleancache allows those pages to be +saved and reclaimed if overall host system memory conditions allow. + +And the identical interface used for cleancache can be used in +physical systems as well. The zcache driver acts as a memory-hungry +device that stores pages of data in a compressed state. And +the proposed "RAMster" driver shares RAM across multiple physical +systems. + +2) Why does cleancache have its sticky fingers so deep inside the + filesystems and VFS? (Andrew Morton and Christoph Hellwig) + +The core hooks for cleancache in VFS are in most cases a single line +and the minimum set are placed precisely where needed to maintain +coherency (via cleancache_flush operations) between cleancache, +the page cache, and disk. All hooks compile into nothingness if +cleancache is config'ed off and turn into a function-pointer- +compare-to-NULL if config'ed on but no backend claims the ops +functions, or to a compare-struct-element-to-negative if a +backend claims the ops functions but a filesystem doesn't enable +cleancache. + +Some filesystems are built entirely on top of VFS and the hooks +in VFS are sufficient, so don't require an "init_fs" hook; the +initial implementation of cleancache didn't provide this hook. +But for some filesystems (such as btrfs), the VFS hooks are +incomplete and one or more hooks in fs-specific code are required. +And for some other filesystems, such as tmpfs, cleancache may +be counterproductive. So it seemed prudent to require a filesystem +to "opt in" to use cleancache, which requires adding a hook in +each filesystem. Not all filesystems are supported by cleancache +only because they haven't been tested. The existing set should +be sufficient to validate the concept, the opt-in approach means +that untested filesystems are not affected, and the hooks in the +existing filesystems should make it very easy to add more +filesystems in the future. + +The total impact of the hooks to existing fs and mm files is only +about 40 lines added (not counting comments and blank lines). + +3) Why not make cleancache asynchronous and batched so it can + more easily interface with real devices with DMA instead + of copying each individual page? (Minchan Kim) + +The one-page-at-a-time copy semantics simplifies the implementation +on both the frontend and backend and also allows the backend to +do fancy things on-the-fly like page compression and +page deduplication. And since the data is "gone" (copied into/out +of the pageframe) before the cleancache get/put call returns, +a great deal of race conditions and potential coherency issues +are avoided. While the interface seems odd for a "real device" +or for real kernel-addressable RAM, it makes perfect sense for +transcendent memory. + +4) Why is non-shared cleancache "exclusive"? And where is the + page "flushed" after a "get"? (Minchan Kim) + +The main reason is to free up space in transcendent memory and +to avoid unnecessary cleancache_flush calls. If you want inclusive, +the page can be "put" immediately following the "get". If +put-after-get for inclusive becomes common, the interface could +be easily extended to add a "get_no_flush" call. + +The flush is done by the cleancache backend implementation. + +5) What's the performance impact? + +Performance analysis has been presented at OLS'09 and LCA'10. +Briefly, performance gains can be significant on most workloads, +especially when memory pressure is high (e.g. when RAM is +overcommitted in a virtual workload); and because the hooks are +invoked primarily in place of or in addition to a disk read/write, +overhead is negligible even in worst case workloads. Basically +cleancache replaces I/O with memory-copy-CPU-overhead; on older +single-core systems with slow memory-copy speeds, cleancache +has little value, but in newer multicore machines, especially +consolidated/virtualized machines, it has great value. + +6) How do I add cleancache support for filesystem X? (Boaz Harrash) + +Filesystems that are well-behaved and conform to certain +restrictions can utilize cleancache simply by making a call to +cleancache_init_fs at mount time. Unusual, misbehaving, or +poorly layered filesystems must either add additional hooks +and/or undergo extensive additional testing... or should just +not enable the optional cleancache. + +Some points for a filesystem to consider: + +- The FS should be block-device-based (e.g. a ram-based FS such + as tmpfs should not enable cleancache) +- To ensure coherency/correctness, the FS must ensure that all + file removal or truncation operations either go through VFS or + add hooks to do the equivalent cleancache "flush" operations +- To ensure coherency/correctness, either inode numbers must + be unique across the lifetime of the on-disk file OR the + FS must provide an "encode_fh" function. +- The FS must call the VFS superblock alloc and deactivate routines + or add hooks to do the equivalent cleancache calls done there. +- To maximize performance, all pages fetched from the FS should + go through the do_mpag_readpage routine or the FS should add + hooks to do the equivalent (cf. btrfs) +- Currently, the FS blocksize must be the same as PAGESIZE. This + is not an architectural restriction, but no backends currently + support anything different. +- A clustered FS should invoke the "shared_init_fs" cleancache + hook to get best performance for some backends. + +7) Why not use the KVA of the inode as the key? (Christoph Hellwig) + +If cleancache would use the inode virtual address instead of +inode/filehandle, the pool id could be eliminated. But, this +won't work because cleancache retains pagecache data pages +persistently even when the inode has been pruned from the +inode unused list, and only flushes the data page if the file +gets removed/truncated. So if cleancache used the inode kva, +there would be potential coherency issues if/when the inode +kva is reused for a different file. Alternately, if cleancache +flushed the pages when the inode kva was freed, much of the value +of cleancache would be lost because the cache of pages in cleanache +is potentially much larger than the kernel pagecache and is most +useful if the pages survive inode cache removal. + +8) Why is a global variable required? + +The cleancache_enabled flag is checked in all of the frequently-used +cleancache hooks. The alternative is a function call to check a static +variable. Since cleancache is enabled dynamically at runtime, systems +that don't enable cleancache would suffer thousands (possibly +tens-of-thousands) of unnecessary function calls per second. So the +global variable allows cleancache to be enabled by default at compile +time, but have insignificant performance impact when cleancache remains +disabled at runtime. + +9) Does cleanache work with KVM? + +The memory model of KVM is sufficiently different that a cleancache +backend may have less value for KVM. This remains to be tested, +especially in an overcommitted system. + +10) Does cleancache work in userspace? It sounds useful for + memory hungry caches like web browsers. (Jamie Lokier) + +No plans yet, though we agree it sounds useful, at least for +apps that bypass the page cache (e.g. O_DIRECT). + +Last updated: Dan Magenheimer, April 13 2011 diff --git a/Documentation/vm/locking b/Documentation/vm/locking index 25fadb4..f61228b 100644 --- a/Documentation/vm/locking +++ b/Documentation/vm/locking @@ -66,7 +66,7 @@ in some cases it is not really needed. Eg, vm_start is modified by expand_stack(), it is hard to come up with a destructive scenario without having the vmlist protection in this case. -The page_table_lock nests with the inode i_mmap_lock and the kmem cache +The page_table_lock nests with the inode i_mmap_mutex and the kmem cache c_spinlock spinlocks. This is okay, since the kmem code asks for pages after dropping c_spinlock. The page_table_lock also nests with pagecache_lock and pagemap_lru_lock spinlocks, and no code asks for memory with these locks |
