diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads | 5 | ||||
| -rw-r--r-- | Documentation/cgroups/hugetlb.txt | 45 | ||||
| -rw-r--r-- | Documentation/cgroups/memory.txt | 12 | ||||
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/Locking | 13 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 12 | ||||
| -rw-r--r-- | Documentation/sysctl/vm.txt | 30 |
7 files changed, 104 insertions, 21 deletions
diff --git a/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads b/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads new file mode 100644 index 0000000..b0b0eeb --- /dev/null +++ b/Documentation/ABI/obsolete/proc-sys-vm-nr_pdflush_threads @@ -0,0 +1,5 @@ +What: /proc/sys/vm/nr_pdflush_threads +Date: June 2012 +Contact: Wanpeng Li <liwp@linux.vnet.ibm.com> +Description: Since pdflush is replaced by per-BDI flusher, the interface of old pdflush + exported in /proc/sys/vm/ should be removed. diff --git a/Documentation/cgroups/hugetlb.txt b/Documentation/cgroups/hugetlb.txt new file mode 100644 index 0000000..a9faaca --- /dev/null +++ b/Documentation/cgroups/hugetlb.txt @@ -0,0 +1,45 @@ +HugeTLB Controller +------------------- + +The HugeTLB controller allows to limit the HugeTLB usage per control group and +enforces the controller limit during page fault. Since HugeTLB doesn't +support page reclaim, enforcing the limit at page fault time implies that, +the application will get SIGBUS signal if it tries to access HugeTLB pages +beyond its limit. This requires the application to know beforehand how much +HugeTLB pages it would require for its use. + +HugeTLB controller can be created by first mounting the cgroup filesystem. + +# mount -t cgroup -o hugetlb none /sys/fs/cgroup + +With the above step, the initial or the parent HugeTLB group becomes +visible at /sys/fs/cgroup. At bootup, this group includes all the tasks in +the system. /sys/fs/cgroup/tasks lists the tasks in this cgroup. + +New groups can be created under the parent group /sys/fs/cgroup. + +# cd /sys/fs/cgroup +# mkdir g1 +# echo $$ > g1/tasks + +The above steps create a new group g1 and move the current shell +process (bash) into it. + +Brief summary of control files + + hugetlb.<hugepagesize>.limit_in_bytes # set/show limit of "hugepagesize" hugetlb usage + hugetlb.<hugepagesize>.max_usage_in_bytes # show max "hugepagesize" hugetlb usage recorded + hugetlb.<hugepagesize>.usage_in_bytes # show current res_counter usage for "hugepagesize" hugetlb + hugetlb.<hugepagesize>.failcnt # show the number of allocation failure due to HugeTLB limit + +For a system supporting two hugepage size (16M and 16G) the control +files include: + +hugetlb.16GB.limit_in_bytes +hugetlb.16GB.max_usage_in_bytes +hugetlb.16GB.usage_in_bytes +hugetlb.16GB.failcnt +hugetlb.16MB.limit_in_bytes +hugetlb.16MB.max_usage_in_bytes +hugetlb.16MB.usage_in_bytes +hugetlb.16MB.failcnt diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index dd88540..4372e6b 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -73,6 +73,8 @@ Brief summary of control files. memory.kmem.tcp.limit_in_bytes # set/show hard limit for tcp buf memory memory.kmem.tcp.usage_in_bytes # show current tcp buf memory allocation + memory.kmem.tcp.failcnt # show the number of tcp buf memory usage hits limits + memory.kmem.tcp.max_usage_in_bytes # show max tcp buf memory usage recorded 1. History @@ -187,12 +189,12 @@ the cgroup that brought it in -- this will happen on memory pressure). But see section 8.2: when moving a task to another cgroup, its pages may be recharged to the new cgroup, if move_charge_at_immigrate has been chosen. -Exception: If CONFIG_CGROUP_CGROUP_MEM_RES_CTLR_SWAP is not used. +Exception: If CONFIG_CGROUP_CGROUP_MEMCG_SWAP is not used. When you do swapoff and make swapped-out pages of shmem(tmpfs) to be backed into memory in force, charges for pages are accounted against the caller of swapoff rather than the users of shmem. -2.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP) +2.4 Swap Extension (CONFIG_MEMCG_SWAP) Swap Extension allows you to record charge for swap. A swapped-in page is charged back to original page allocator if possible. @@ -259,7 +261,7 @@ When oom event notifier is registered, event will be delivered. per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by zone->lru_lock, it has no lock of its own. -2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM) +2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM) With the Kernel memory extension, the Memory Controller is able to limit the amount of kernel memory used by the system. Kernel memory is fundamentally @@ -286,8 +288,8 @@ per cgroup, instead of globally. a. Enable CONFIG_CGROUPS b. Enable CONFIG_RESOURCE_COUNTERS -c. Enable CONFIG_CGROUP_MEM_RES_CTLR -d. Enable CONFIG_CGROUP_MEM_RES_CTLR_SWAP (to use swap extension) +c. Enable CONFIG_MEMCG +d. Enable CONFIG_MEMCG_SWAP (to use swap extension) 1. Prepare the cgroups (see cgroups.txt, Why are cgroups needed?) # mount -t tmpfs none /sys/fs/cgroup diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 24fec760..72ed150 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -13,6 +13,14 @@ Who: Jim Cromie <jim.cromie@gmail.com>, Jason Baron <jbaron@redhat.com> --------------------------- +What: /proc/sys/vm/nr_pdflush_threads +When: 2012 +Why: Since pdflush is deprecated, the interface exported in /proc/sys/vm/ + should be removed. +Who: Wanpeng Li <liwp@linux.vnet.ibm.com> + +--------------------------- + What: CONFIG_APM_CPU_IDLE, and its ability to call APM BIOS in idle When: 2012 Why: This optional sub-feature of APM is of dubious reliability, diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index e0cce2a..2db1900 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -206,6 +206,8 @@ prototypes: int (*launder_page)(struct page *); int (*is_partially_uptodate)(struct page *, read_descriptor_t *, unsigned long); int (*error_remove_page)(struct address_space *, struct page *); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); locking rules: All except set_page_dirty and freepage may block @@ -229,6 +231,8 @@ migratepage: yes (both) launder_page: yes is_partially_uptodate: yes error_remove_page: yes +swap_activate: no +swap_deactivate: no ->write_begin(), ->write_end(), ->sync_page() and ->readpage() may be called from the request handler (/dev/loop). @@ -330,6 +334,15 @@ cleaned, or an error value if not. Note that in order to prevent the page getting mapped back in and redirtied, it needs to be kept locked across the entire operation. + ->swap_activate will be called with a non-zero argument on +files backing (non block device backed) swapfiles. A return value +of zero indicates success, in which case this file can be used for +backing swapspace. The swapspace operations will be proxied to the +address space operations. + + ->swap_deactivate() will be called in the sys_swapoff() +path after ->swap_activate() returned success. + ----------------------- file_lock_operations ------------------------------ prototypes: void (*fl_copy_lock)(struct file_lock *, struct file_lock *); diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index aa754e0..065aa2d 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -592,6 +592,8 @@ struct address_space_operations { int (*migratepage) (struct page *, struct page *); int (*launder_page) (struct page *); int (*error_remove_page) (struct mapping *mapping, struct page *page); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); }; writepage: called by the VM to write a dirty page to backing store. @@ -760,6 +762,16 @@ struct address_space_operations { Setting this implies you deal with pages going away under you, unless you have them locked or reference counts increased. + swap_activate: Called when swapon is used on a file to allocate + space if necessary and pin the block lookup information in + memory. A return value of zero indicates success, + in which case this file can be used to back swapspace. The + swapspace operations will be proxied to this address space's + ->swap_{out,in} methods. + + swap_deactivate: Called during swapoff on files where swap_activate + was successful. + The File Object =============== diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 96f0ee8..dcc2a94 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -42,7 +42,6 @@ Currently, these files are in /proc/sys/vm: - mmap_min_addr - nr_hugepages - nr_overcommit_hugepages -- nr_pdflush_threads - nr_trim_pages (only if CONFIG_MMU=n) - numa_zonelist_order - oom_dump_tasks @@ -426,16 +425,6 @@ See Documentation/vm/hugetlbpage.txt ============================================================== -nr_pdflush_threads - -The current number of pdflush threads. This value is read-only. -The value changes according to the number of dirty pages in the system. - -When necessary, additional pdflush threads are created, one per second, up to -nr_pdflush_threads_max. - -============================================================== - nr_trim_pages This is available only on NOMMU kernels. @@ -502,9 +491,10 @@ oom_dump_tasks Enables a system-wide task dump (excluding kernel threads) to be produced when the kernel performs an OOM-killing and includes such -information as pid, uid, tgid, vm size, rss, cpu, oom_adj score, and -name. This is helpful to determine why the OOM killer was invoked -and to identify the rogue task that caused it. +information as pid, uid, tgid, vm size, rss, nr_ptes, swapents, +oom_score_adj score, and name. This is helpful to determine why the +OOM killer was invoked, to identify the rogue task that caused it, +and to determine why the OOM killer chose the task it did to kill. If this is set to zero, this information is suppressed. On very large systems with thousands of tasks it may not be feasible to dump @@ -574,16 +564,24 @@ of physical RAM. See above. page-cluster -page-cluster controls the number of pages which are written to swap in -a single attempt. The swap I/O size. +page-cluster controls the number of pages up to which consecutive pages +are read in from swap in a single attempt. This is the swap counterpart +to page cache readahead. +The mentioned consecutivity is not in terms of virtual/physical addresses, +but consecutive on swap space - that means they were swapped out together. It is a logarithmic value - setting it to zero means "1 page", setting it to 1 means "2 pages", setting it to 2 means "4 pages", etc. +Zero disables swap readahead completely. The default value is three (eight pages at a time). There may be some small benefits in tuning this to a different value if your workload is swap-intensive. +Lower values mean lower latencies for initial faults, but at the same time +extra faults and I/O delays for following faults if they would have been part of +that consecutive pages readahead would have brought in. + ============================================================= panic_on_oom |
