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* modules: add ro_after_init supportJessica Yu2016-08-042-13/+55
| | | | | | | | | | Add ro_after_init support for modules by adding a new page-aligned section in the module layout (after rodata) for ro_after_init data and enabling RO protection for that section after module init runs. Signed-off-by: Jessica Yu <jeyu@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* jump_label: disable preemption around __module_text_address().Rusty Russell2016-08-041-1/+4
| | | | | | | | | | Steven reported a warning caused by not holding module_mutex or rcu_read_lock_sched: his backtrace was corrupted but a quick audit found this possible cause. It's wrong anyway... Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* modules: Add kernel parameter to blacklist modulesPrarit Bhargava2016-08-041-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | Blacklisting a module in linux has long been a problem. The current procedure is to use rd.blacklist=module_name, however, that doesn't cover the case after the initramfs and before a boot prompt (where one is supposed to use /etc/modprobe.d/blacklist.conf to blacklist runtime loading). Using rd.shell to get an early prompt is hit-or-miss, and doesn't cover all situations AFAICT. This patch adds this functionality of permanently blacklisting a module by its name via the kernel parameter module_blacklist=module_name. [v2]: Rusty, use core_param() instead of __setup() which simplifies things. [v3]: Rusty, undo wreckage from strsep() [v4]: Rusty, simpler version of blacklisted() Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-doc@vger.kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: Do a WARN_ON_ONCE() for assert module mutex not heldSteven Rostedt2016-08-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running with lockdep enabled, I triggered the WARN_ON() in the module code that asserts when module_mutex or rcu_read_lock_sched are not held. The issue I have is that this can also be called from the dump_stack() code, causing us to enter an infinite loop... ------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 ffff880215e8fa70 ffff880215e8fa70 ffffffff812fc8e3 0000000000000000 ffffffff81d3e55b ffff880215e8fac0 ffffffff8104fc88 ffffffff8104fcab 0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001 Call Trace: [<ffffffff812fc8e3>] dump_stack+0x67/0x90 [<ffffffff8104fc88>] __warn+0xcb/0xe9 [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f ------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 ffff880215e8f7a0 ffff880215e8f7a0 ffffffff812fc8e3 0000000000000000 ffffffff81d3e55b ffff880215e8f7f0 ffffffff8104fc88 ffffffff8104fcab 0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001 Call Trace: [<ffffffff812fc8e3>] dump_stack+0x67/0x90 [<ffffffff8104fc88>] __warn+0xcb/0xe9 [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f ------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e Modules linked in: ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc3-test-00013-g501c2375253c #14 Hardware name: MSI MS-7823/CSM-H87M-G43 (MS-7823), BIOS V1.6 02/22/2014 ffff880215e8f4d0 ffff880215e8f4d0 ffffffff812fc8e3 0000000000000000 ffffffff81d3e55b ffff880215e8f520 ffffffff8104fc88 ffffffff8104fcab 0000000915e88300 0000000000000046 ffffffffa019b29a 0000000000000001 Call Trace: [<ffffffff812fc8e3>] dump_stack+0x67/0x90 [<ffffffff8104fc88>] __warn+0xcb/0xe9 [<ffffffff8104fcab>] ? warn_slowpath_null+0x5/0x1f ------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at kernel/module.c:268 module_assert_mutex_or_preempt+0x3c/0x3e [...] Which gives us rather useless information. Worse yet, there's some race that causes this, and I seldom trigger it, so I have no idea what happened. This would not be an issue if that warning was a WARN_ON_ONCE(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: Invalidate signatures on force-loaded modulesBen Hutchings2016-07-271-4/+9
| | | | | | | | | | | | Signing a module should only make it trusted by the specific kernel it was built for, not anything else. Loading a signed module meant for a kernel with a different ABI could have interesting effects. Therefore, treat all signatures as invalid when a module is force-loaded. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: Issue warnings when tainting kernelLibor Pechacek2016-07-271-1/+10
| | | | | | | | | | While most of the locations where a kernel taint bit is set are accompanied with a warning message, there are two which set their bits silently. If the tainting module gets unloaded later on, it is almost impossible to tell what was the reason for setting the flag. Signed-off-by: Libor Pechacek <lpechacek@suse.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix redundant test.Rusty Russell2016-07-271-2/+1
| | | | | | | | | | | | | | [linux-4.5-rc4/kernel/module.c:1692]: (style) Redundant condition: attr.test. '!attr.test || (attr.test && attr.test(mod))' is equivalent to '!attr.test || attr.test(mod)' This code was added like this ten years ago, in c988d2b284549 "modules: add version and srcversion to sysfs". Reported-by: David Binderman <dcb314@hotmail.com> Cc: Matt Domsch <Matt_Domsch@dell.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix noreturn attribute for __module_put_and_exit()Jiri Kosina2016-07-271-1/+1
| | | | | | | | | | __module_put_and_exit() is makred noreturn in module.h declaration, but is lacking the attribute in the definition, which makes some tools (such as sparse) unhappy. Amend the definition with the attribute as well (and reformat the declaration so that it uses more common format). Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Merge branch 'for-4.8/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds2016-07-261-2/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block driver updates from Jens Axboe: "This branch also contains core changes. I've come to the conclusion that from 4.9 and forward, I'll be doing just a single branch. We often have dependencies between core and drivers, and it's hard to always split them up appropriately without pulling core into drivers when that happens. That said, this contains: - separate secure erase type for the core block layer, from Christoph. - set of discard fixes, from Christoph. - bio shrinking fixes from Christoph, as a followup up to the op/flags change in the core branch. - map and append request fixes from Christoph. - NVMeF (NVMe over Fabrics) code from Christoph. This is pretty exciting! - nvme-loop fixes from Arnd. - removal of ->driverfs_dev from Dan, after providing a device_add_disk() helper. - bcache fixes from Bhaktipriya and Yijing. - cdrom subchannel read fix from Vchannaiah. - set of lightnvm updates from Wenwei, Matias, Johannes, and Javier. - set of drbd updates and fixes from Fabian, Lars, and Philipp. - mg_disk error path fix from Bart. - user notification for failed device add for loop, from Minfei. - NVMe in general: + NVMe delay quirk from Guilherme. + SR-IOV support and command retry limits from Keith. + fix for memory-less NUMA node from Masayoshi. + use UINT_MAX for discard sectors, from Minfei. + cancel IO fixes from Ming. + don't allocate unused major, from Neil. + error code fixup from Dan. + use constants for PSDT/FUSE from James. + variable init fix from Jay. + fabrics fixes from Ming, Sagi, and Wei. + various fixes" * 'for-4.8/drivers' of git://git.kernel.dk/linux-block: (115 commits) nvme/pci: Provide SR-IOV support nvme: initialize variable before logical OR'ing it block: unexport various bio mapping helpers scsi/osd: open code blk_make_request target: stop using blk_make_request block: simplify and export blk_rq_append_bio block: ensure bios return from blk_get_request are properly initialized virtio_blk: use blk_rq_map_kern memstick: don't allow REQ_TYPE_BLOCK_PC requests block: shrink bio size again block: simplify and cleanup bvec pool handling block: get rid of bio_rw and READA block: don't ignore -EOPNOTSUPP blkdev_issue_write_same block: introduce BLKDEV_DISCARD_ZERO to fix zeroout NVMe: don't allocate unused nvme_major nvme: avoid crashes when node 0 is memoryless node. nvme: Limit command retries loop: Make user notify for adding loop device failed nvme-loop: fix nvme-loop Kconfig dependencies nvmet: fix return value check in nvmet_subsys_alloc() ...
| * block: add a separate operation type for secure eraseChristoph Hellwig2016-06-091-2/+4
| | | | | | | | | | | | | | | | | | | | Instead of overloading the discard support with the REQ_SECURE flag. Use the opportunity to rename the queue flag as well, and remove the dead checks for this flag in the RAID 1 and RAID 10 drivers that don't claim support for secure erase. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* | Merge branch 'for-4.8/core' of git://git.kernel.dk/linux-blockLinus Torvalds2016-07-262-43/+67
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block updates from Jens Axboe: - the big change is the cleanup from Mike Christie, cleaning up our uses of command types and modified flags. This is what will throw some merge conflicts - regression fix for the above for btrfs, from Vincent - following up to the above, better packing of struct request from Christoph - a 2038 fix for blktrace from Arnd - a few trivial/spelling fixes from Bart Van Assche - a front merge check fix from Damien, which could cause issues on SMR drives - Atari partition fix from Gabriel - convert cfq to highres timers, since jiffies isn't granular enough for some devices these days. From Jan and Jeff - CFQ priority boost fix idle classes, from me - cleanup series from Ming, improving our bio/bvec iteration - a direct issue fix for blk-mq from Omar - fix for plug merging not involving the IO scheduler, like we do for other types of merges. From Tahsin - expose DAX type internally and through sysfs. From Toshi and Yigal * 'for-4.8/core' of git://git.kernel.dk/linux-block: (76 commits) block: Fix front merge check block: do not merge requests without consulting with io scheduler block: Fix spelling in a source code comment block: expose QUEUE_FLAG_DAX in sysfs block: add QUEUE_FLAG_DAX for devices to advertise their DAX support Btrfs: fix comparison in __btrfs_map_block() block: atari: Return early for unsupported sector size Doc: block: Fix a typo in queue-sysfs.txt cfq-iosched: Charge at least 1 jiffie instead of 1 ns cfq-iosched: Fix regression in bonnie++ rewrite performance cfq-iosched: Convert slice_resid from u64 to s64 block: Convert fifo_time from ulong to u64 blktrace: avoid using timespec block/blk-cgroup.c: Declare local symbols static block/bio-integrity.c: Add #include "blk.h" block/partition-generic.c: Remove a set-but-not-used variable block: bio: kill BIO_MAX_SIZE cfq-iosched: temporarily boost queue priority for idle classes block: drbd: avoid to use BIO_MAX_SIZE block: bio: remove BIO_MAX_SECTORS ...
| * | blktrace: avoid using timespecArnd Bergmann2016-06-171-3/+4
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The blktrace code stores the current time in a 32-bit word in its user interface. This is a bad idea because 32-bit seconds overflow at some point. We probably have until 2106 before this one overflows, as it seems to use an 'unsigned' variable, but we should confirm that user space treats it the same way. Aside from this, we want to stop using 'struct timespec' here, so I'm adding a comment about the overflow and change the code to use timespec64 instead to make the loss of range more obvious. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@fb.com>
| * block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSHMike Christie2016-06-071-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | To avoid confusion between REQ_OP_FLUSH, which is handled by request_fn drivers, and upper layers requesting the block layer perform a flush sequence along with possibly a WRITE, this patch renames REQ_FLUSH to REQ_PREFLUSH. Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * block, drivers: add REQ_OP_FLUSH operationMike Christie2016-06-071-0/+5
| | | | | | | | | | | | | | | | | | | | | | This adds a REQ_OP_FLUSH operation that is sent to request_fn based drivers by the block layer's flush code, instead of sending requests with the request->cmd_flags REQ_FLUSH bit set. Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * blktrace: use op accessorsMike Christie2016-06-071-26/+36
| | | | | | | | | | | | | | | | | | Have blktrace use the req/bio op accessor to get the REQ_OP. Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * pm: use bio op accessorsMike Christie2016-06-071-12/+18
| | | | | | | | | | | | | | | | | | | | Separate the op from the rq_flag_bits and have the pm code set/get the bio using bio_set_op_attrs/bio_op. Signed-off-by: Mike Christie <mchristi@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * block/fs/drivers: remove rw argument from submit_bioMike Christie2016-06-071-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | This has callers of submit_bio/submit_bio_wait set the bio->bi_rw instead of passing it in. This makes that use the same as generic_make_request and how we set the other bio fields. Signed-off-by: Mike Christie <mchristi@redhat.com> Fixed up fs/ext4/crypto.c Signed-off-by: Jens Axboe <axboe@fb.com>
* | Merge branch 'for-4.8' of ↵Linus Torvalds2016-07-262-10/+37
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "Nothing too exciting. - updates to the pids controller so that pid limit breaches can be noticed and monitored from userland. - cleanups and non-critical bug fixes" * 'for-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: remove duplicated include from cgroup.c cgroup: Use lld instead of ld when printing pids controller events_limit cgroup: Add pids controller event when fork fails because of pid limit cgroup: allow NULL return from ss->css_alloc() cgroup: remove unnecessary 0 check from css_from_id() cgroup: fix idr leak for the first cgroup root
| * | cgroup: remove duplicated include from cgroup.cWei Yongjun2016-07-191-1/+0
| | | | | | | | | | | | | | | | | | | | | Remove duplicated include. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: Use lld instead of ld when printing pids controller events_limitKenny Yu2016-06-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The `events_limit` variable needs to be formatted with %lld and not %ld. This fixes the following warning discovered by kbuild test robot: kernel/cgroup_pids.c: In function 'pids_events_show': kernel/cgroup_pids.c:313:24: warning: format '%ld' expects argument of type 'long int', but argument 3 has type 'long long int' [-Wformat=] seq_printf(sf, "max %ld\n", atomic64_read(&pids->events_limit)); ^ tj: Added explicit (s64) cast as atomic64 switches between long long and long depending on 32 or 64. Signed-off-by: Kenny Yu <kennyyu@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: Add pids controller event when fork fails because of pid limitKenny Yu2016-06-211-1/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds more visibility into the pids controller when the controller rejects a fork request. Whenever fork fails because the limit on the number of pids in the cgroup is reached, the controller will log this and also notify the newly added cgroups events file. The `max` key in the events file represents the number of times fork failed because of the pids controller. This change also logs only the first time the `max` event counter is incremented. This is to provide a hint to the user to understand why fork failed, as users are not yet used to seeing fork failures because of the pids controller. Signed-off-by: Kenny Yu <kennyyu@fb.com> Acked-by: Johannes Weiner <hannes <at> cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: allow NULL return from ss->css_alloc()Tejun Heo2016-06-211-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cgroup core expected css_alloc to return an ERR_PTR value on failure and caused NULL deref if it returned NULL. It's an easy mistake to make from an alloc function and there's no ambiguity in what's being indicated. Update css_create() so that it interprets NULL return from css_alloc as -ENOMEM. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: remove unnecessary 0 check from css_from_id()Johannes Weiner2016-06-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | css_idr allocation starts at 1, so index 0 will never point to an item. css_from_id() currently filters that before asking idr_find(), but idr_find() would also just return NULL, so this is not needed. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | cgroup: fix idr leak for the first cgroup rootJohannes Weiner2016-06-171-7/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The valid cgroup hierarchy ID range includes 0, so we can't filter for positive numbers when freeing it, or it'll leak the first ID. No big deal, just disruptive when reading the code. The ID is freed during error handling and when the reference count hits zero, so the double-free test is not necessary; remove it. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Tejun Heo <tj@kernel.org>
* | | Merge branch 'irq-core-for-linus' of ↵Linus Torvalds2016-07-2511-66/+358
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "The irq department delivers: - new core infrastructure to allow better management of multi-queue devices (interrupt spreading, node aware descriptor allocation ...) - a new interrupt flow handler to support the new fangled Intel VMD devices. - yet another new interrupt controller driver. - a series of fixes which addresses sparse warnings, missing includes, missing static declarations etc from Ben Dooks. - a fix for the error handling in the hierarchical domain allocation code. - the usual pile of small updates to core and driver code" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits) genirq: Fix missing irq allocation affinity hint irqdomain: Fix irq_domain_alloc_irqs_recursive() error handling irq/Documentation: Correct result of echnoing 5 to smp_affinity MAINTAINERS: Remove Jiang Liu from irq domains genirq/msi: Fix broken debug output genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectors genirq/msi: Make use of affinity aware allocations genirq: Use affinity hint in irqdesc allocation genirq: Add affinity hint to irq allocation genirq: Introduce IRQD_AFFINITY_MANAGED flag genirq/msi: Remove unused MSI_FLAG_IDENTITY_MAP irqchip/s3c24xx: Fixup IO accessors for big endian irqchip/exynos-combiner: Fix usage of __raw IO irqdomain: Fix disposal of mappings for interrupt hierarchies irqchip/aspeed-vic: Add irq controller for Aspeed doc/devicetree: Add Aspeed VIC bindings x86/PCI/VMD: Use untracked irq handler genirq: Add untracked irq handler irqchip/mips-gic: Populate irq_domain names irqchip/gicv3-its: Implement two-level(indirect) device table support ...
| * | | genirq: Fix missing irq allocation affinity hintVincent Stehle2016-07-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new affinity hint argument of __irq_domain_alloc_irqs() is missing in irq_reserve_ipi(). Add it. This fixes the following compilation error: kernel/irq/ipi.c: In function ‘irq_reserve_ipi’: kernel/irq/ipi.c:85:9: error: too few arguments to function ‘__irq_domain_alloc_irqs’ virq = __irq_domain_alloc_irqs(domain, virq, nr_irqs, NUMA_NO_NODE, ^ Fixes: 06ee6d571f0e ("genirq: Add affinity hint to irq allocation") Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> Cc: linux-pci@vger.kernel.org Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | irqdomain: Fix irq_domain_alloc_irqs_recursive() error handlingAlexander Popov2016-07-111-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an irq_domain is auto-recursive and irq_domain_alloc_irqs_recursive() for its parent has returned an error, then do return and avoid calling irq_domain_free_irqs_recursive() uselessly, because: - if domain->ops->alloc() had failed for an auto-recursive irq_domain, then irq_domain_free_irqs_recursive() had already been called; - if domain->ops->alloc() had failed for a not auto-recursive irq_domain, then there is nothing to free at all. Signed-off-by: Alexander Popov <alex.popov@linux.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Link: http://lkml.kernel.org/r/1467505448-2850-1-git-send-email-alex.popov@linux.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | genirq/msi: Fix broken debug outputThomas Gleixner2016-07-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | virq is not required to be the same for all msi descs. Use the base irq number from the desc in the debug printk. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | Merge branch 'irq/for-block' into irq/coreThomas Gleixner2016-07-0434-245/+543
| |\ \ \ | | | | | | | | | | | | | | | | | | | | Pull the irq affinity managing code which is in a seperate branch for block developers to pull.
| | * | | genirq: Add a helper to spread an affinity mask for MSI/MSI-X vectorsChristoph Hellwig2016-07-042-0/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is lifted from the blk-mq code and adopted to use the affinity mask concept just introduced in the irq handling code. It tries to keep the algorithm the same as the one current used by blk-mq, but improvements like assining vectors on a per-node basis instead of just per sibling are possible with this simple move and refactoring. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-7-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * | | genirq/msi: Make use of affinity aware allocationsThomas Gleixner2016-07-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the MSI code to provide affinity hints per MSI descriptor. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-6-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * | | genirq: Use affinity hint in irqdesc allocationThomas Gleixner2016-07-041-12/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the affinity hint in the irqdesc allocator. The hint is used to determine the node for the allocation and to set the affinity of the interrupt. If multiple interrupts are allocated (multi-MSI) then the allocator iterates over the cpumask and for each set cpu it allocates on their node and sets the initial affinity to that cpu. If a single interrupt is allocated (MSI-X) then the allocator uses the first cpu in the mask to compute the allocation node and uses the mask for the initial affinity setting. Interrupts set up this way are marked with the AFFINITY_MANAGED flag to prevent userspace from messing with their affinity settings. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-5-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * | | genirq: Add affinity hint to irq allocationThomas Gleixner2016-07-045-17/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add an extra argument to the irq(domain) allocation functions, so we can hand down affinity hints to the allocator. Thats necessary to implement proper support for multiqueue devices. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-4-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * | | genirq: Introduce IRQD_AFFINITY_MANAGED flagThomas Gleixner2016-07-043-4/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Interupts marked with this flag are excluded from user space interrupt affinity changes. Contrary to the IRQ_NO_BALANCING flag, the kernel internal affinity mechanism is not blocked. This flag will be used for multi-queue device interrupts. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-3-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| | * | | genirq/msi: Remove unused MSI_FLAG_IDENTITY_MAPThomas Gleixner2016-07-041-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No user and we definitely don't want to grow one. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-2-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | irqdomain: Fix disposal of mappings for interrupt hierarchiesJon Hunter2016-06-231-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function irq_create_of_mapping() is used to create an interrupt mapping. However, depending on whether the irqdomain, to which the interrupt belongs, is part of a hierarchy, determines whether the mapping is created via calling irq_domain_alloc_irqs() or irq_create_mapping(). To dispose of the interrupt mapping, drivers call irq_dispose_mapping(). However, this function does not check to see if the irqdomain is part of a hierarchy or not and simply assumes that it was mapped via calling irq_create_mapping() so calls irq_domain_disassociate() to unmap the interrupt. Fix this by checking to see if the irqdomain is part of a hierarchy and if so call irq_domain_free_irqs() to free/unmap the interrupt. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Link: http://lkml.kernel.org/r/1466501002-16368-1-git-send-email-jonathanh@nvidia.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | genirq: Add untracked irq handlerKeith Busch2016-06-183-4/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a software irq handler for controllers that multiplex interrupts from multiple devices, but don't know which device generated the interrupt. For these devices, the irq handler that demuxes must check every action for every software irq using the same h/w irq in order to find out which device generated the interrupt. This will inevitably trigger spurious interrupt detection if we are noting the irq. The new irq handler does not track the handling for spurious interrupt detection. An irq that uses this also won't get stats tracked since it didn't generate the interrupt, nor added to randomness since they are not random. Signed-off-by: Keith Busch <keith.busch@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org Cc: Jon Derrick <jonathan.derrick@intel.com> Link: http://lkml.kernel.org/r/1466200821-29159-1-git-send-email-keith.busch@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | Merge tag 'irqchip-for-4.8' of ↵Thomas Gleixner2016-06-134-10/+134
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/core First drop of irqchip updates for 4.8 from Marc Zyngier: - Fix a few bugs in configuring the default trigger from the irqdomain layer - Make the genirq layer PM aware - Add PM capability to the ARM GIC driver - Add support for 2-level translation tables to the GICv3 ITS driver
| | * | | | genirq: Add runtime power management support for IRQ chipsJon Hunter2016-06-133-1/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some IRQ chips may be located in a power domain outside of the CPU subsystem and hence will require device specific runtime power management. In order to support such IRQ chips, add a pointer for a device structure to the irq_chip structure, and if this pointer is populated by the IRQ chip driver and CONFIG_PM is selected in the kernel configuration, then the pm_runtime_get/put APIs for this chip will be called when an IRQ is requested/freed, respectively. Reviewed-by: Kevin Hilman <khilman@baylibre.com> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | irqdomain: Don't set type when mapping an IRQJon Hunter2016-06-131-5/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some IRQ chips, such as GPIO controllers or secondary level interrupt controllers, may require require additional runtime power management control to ensure they are accessible. For such IRQ chips, it makes sense to enable the IRQ chip when interrupts are requested and disabled them again once all interrupts have been freed. When mapping an IRQ, the IRQ type settings are read and then programmed. The mapping of the IRQ happens before the IRQ is requested and so the programming of the type settings occurs before the IRQ is requested. This is a problem for IRQ chips that require additional power management control because they may not be accessible yet. Therefore, when mapping the IRQ, don't program the type settings, just save them and then program these saved settings when the IRQ is requested (so long as if they are not overridden via the call to request the IRQ). Add a stub function for irq_domain_free_irqs() to avoid any compilation errors when CONFIG_IRQ_DOMAIN_HIERARCHY is not selected. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | genirq: Look-up percpu trigger type if not specified by callerMarc Zyngier2016-06-131-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As we now do for non-percpu interrupt, perform a lookup of the interrupt trigger if the user doesn't supply one. The difference here is that we can only do it at enable time (trigger configuration can be per-cpu as well). Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | genirq: Look-up trigger type if not specified by callerJon Hunter2016-06-131-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For some devices the IRQ trigger type for a device is read from firmware, such as device-tree. The IRQ trigger type is typically read when the mapping for IRQ is created, which is before the IRQ is requested. Hence, the IRQ trigger type is programmed when mapping the IRQ and not when requesting the IRQ. Although this works for most cases, in order to support IRQ chips which require runtime power management, which may not be accessible prior to requesting the IRQ, it is desirable to look-up the IRQ trigger type when it is requested. Therefore, if the IRQ trigger type is not specified when __setup_irq() is called, look-up the saved IRQ trigger type. This will allow us to defer the programming of the trigger type from when the IRQ is mapped to when it is actually requested. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| | * | | | irqdomain: Fix handling of type settings for existing mappingsJon Hunter2016-06-131-5/+32
| | | |_|/ | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When mapping an IRQ, it is possible that a mapping for the IRQ already exists. If mapping does exist then there are the following issues with regard to the handling of the IRQ type settings ... 1. If the domain is part of a hierarchy, then: a. We do not check that the type settings for the existing mapping match those of the new mapping. b. We do not check to see if the type settings have been programmed yet (and they might not have been) and so we may never set the type. 2. If the domain is NOT part of a hierarchy, we will overwrite the current type settings programmed if they are different from the previous mapping. Please note that irq_create_mapping() calls irq_find_mapping() to check if a mapping already exists. Although, it may be unlikely that the type settings for a shared interrupt would not match, nonetheless we should check for this. Therefore, to fix this check if a mapping exists (regardless of whether the domain is part of a hierarchy or not) and if it does then: 1. Return the IRQ number if the type settings match or are not specified. 2. Program the type settings and return the IRQ number if the type settings have not been programmed yet. 3. Otherwise if the type setting do not match, then print a warning and don't return the IRQ number. Furthermore, add a warning if the type return by irq_domain_translate() has bits outside the sense mask set and then clear these bits. If these bits are not cleared then this will cause the comparision of the type settings for an existing mapping to fail with that of the new mapping even if the sense bit themselves match. The reason being is that the existing type settings are read by calling irq_get_trigger_type() which will clear any bits outside the sense mask. This will allow us to detect irqchips that are not correctly clearing these bits and fix them. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
| * | | | genirq: Remove unnecessary memset() callsWeongyo Jeong2016-06-101-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sprintf() and snprintf() implementation of kernel guarantees that its result is terminated with null byte if size is larger than 0. So we don't need to call memset() at all. Signed-off-by: Weongyo Jeong <weongyo.linux@gmail.com> Link: http://lkml.kernel.org/r/1459451703-5744-1-git-send-email-weongyo.linux@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | genirq: Remove redundant NULL check of irq_descJianyu Zhan2016-06-101-5/+1
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | for_each_irq_desc() macro has already skipped NULL irq_desc, don't bother to check it again. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Cc: mingo@kernel.org Cc: yhlu.kernel@gmail.com Link: http://lkml.kernel.org/r/1458395959-7046-1-git-send-email-nasa4836@gmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2016-07-2513-540/+751
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "This update provides the following changes: - The rework of the timer wheel which addresses the shortcomings of the current wheel (cascading, slow search for next expiring timer, etc). That's the first major change of the wheel in almost 20 years since Finn implemted it. - A large overhaul of the clocksource drivers init functions to consolidate the Device Tree initialization - Some more Y2038 updates - A capability fix for timerfd - Yet another clock chip driver - The usual pile of updates, comment improvements all over the place" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (130 commits) tick/nohz: Optimize nohz idle enter clockevents: Make clockevents_subsys static clocksource/drivers/time-armada-370-xp: Fix return value check timers: Implement optimization for same expiry time in mod_timer() timers: Split out index calculation timers: Only wake softirq if necessary timers: Forward the wheel clock whenever possible timers/nohz: Remove pointless tick_nohz_kick_tick() function timers: Optimize collect_expired_timers() for NOHZ timers: Move __run_timers() function timers: Remove set_timer_slack() leftovers timers: Switch to a non-cascading wheel timers: Reduce the CPU index space to 256k timers: Give a few structs and members proper names hlist: Add hlist_is_singular_node() helper signals: Use hrtimer for sigtimedwait() timers: Remove the deprecated mod_timer_pinned() API timers, net/ipv4/inet: Initialize connection request timers as pinned timers, drivers/tty/mips_ejtag: Initialize the poll timer as pinned timers, drivers/tty/metag_da: Initialize the poll timer as pinned ...
| * | | | tick/nohz: Optimize nohz idle enterGaurav Jindal2016-07-191-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tick_nohz_start_idle is called before checking whether the idle tick can be stopped. If the tick cannot be stopped, calling tick_nohz_start_idle() is pointless and just wasting CPU cycles. Only invoke tick_nohz_start_idle() when can_stop_idle_tick() returns true. A short one minute observation of the effect on ARM64 shows a reduction of calls by 1.5% thus optimizing the idle entry sequence. [tglx: Massaged changelog ] Co-developed-by: Sanjeev Yadav<sanjeev.yadav@spreadtrum.com> Signed-off-by: Gaurav Jindal<gaurav.jindal@spreadtrum.com> Link: http://lkml.kernel.org/r/20160714120416.GB21099@gaurav.jindal@spreadtrum.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | clockevents: Make clockevents_subsys staticBen Dooks2016-07-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clockevents_subsys struct is used for sysfs support and is not declared or used outside the file it is defined in. Fix the following warning by making it static: kernel/time/clockevents.c:648:17: warning: symbol 'clockevents_subsys' was not declared. Should it be static? Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Cc: linux-kernel@lists.codethink.co.uk Link: http://lkml.kernel.org/r/1466178974-7105-1-git-send-email-ben.dooks@codethink.co.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | Merge branch 'timers/fast-wheel' into timers/coreIngo Molnar2016-07-0729-692/+1077
| |\ \ \ \
| | * | | | timers: Implement optimization for same expiry time in mod_timer()Anna-Maria Gleixner2016-07-071-16/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The existing optimization for same expiry time in mod_timer() checks whether the timer expiry time is the same as the new requested expiry time. In the old timer wheel implementation this does not take the slack batching into account, neither does the new implementation evaluate whether the new expiry time will requeue the timer to the same bucket. To optimize that, we can calculate the resulting bucket and check if the new expiry time is different from the current expiry time. This calculation happens outside the base lock held region. If the resulting bucket is the same we can avoid taking the base lock and requeueing the timer. If the timer needs to be requeued then we have to check under the base lock whether the base time has changed between the lockless calculation and taking the lock. If it has changed we need to recalculate under the lock. This optimization takes effect for timers which are enqueued into the less granular wheel levels (1 and above). With a simple test case the functionality has been verified: Before After Match: 5.5% 86.6% Requeue: 94.5% 13.4% Recalc: <0.01% In the non optimized case the timer is requeued in 94.5% of the cases. With the index optimization in place the requeue rate drops to 13.4%. The case where the lockless index calculation has to be redone is less than 0.01%. With a real world test case (networking) we observed the following changes: Before After Match: 97.8% 99.7% Requeue: 2.2% 0.3% Recalc: <0.001% That means two percent fewer lock/requeue/unlock operations done in one of the hot path use cases of timers. Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Chris Mason <clm@fb.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Len Brown <lenb@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160704094342.778527749@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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