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2018-12-29Merge branch 'for-4.21' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - Waiman's cgroup2 cpuset support has been finally merged closing one of the last remaining feature gaps. - cgroup.procs could show non-leader threads when cgroup2 threaded mode was used in certain ways. I forgot to push the fix during the last cycle. - A patch to fix mount option parsing when all mount options have been consumed by someone else (LSM). - cgroup_no_v1 boot param can now block named cgroup1 hierarchies too. * 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: Add named hierarchy disabling to cgroup_no_v1 boot param cgroup: fix parsing empty mount option string cpuset: Remove set but not used variable 'cs' cgroup: fix CSS_TASK_ITER_PROCS cgroup: Add .__DEBUG__. prefix to debug file names cpuset: Minor cgroup2 interface updates cpuset: Expose cpuset.cpus.subpartitions with cgroup_debug cpuset: Add documentation about the new "cpuset.sched.partition" flag cpuset: Use descriptive text when reading/writing cpuset.sched.partition cpuset: Expose cpus.effective and mems.effective on cgroup v2 root cpuset: Make generate_sched_domains() work with partition cpuset: Make CPU hotplug work with partition cpuset: Track cpusets that use parent's effective_cpus cpuset: Add an error state to cpuset.sched.partition cpuset: Add new v2 cpuset.sched.partition flag cpuset: Simply allocation and freeing of cpumasks cpuset: Define data structures to support scheduling partition cpuset: Enable cpuset controller in default hierarchy cgroup: remove unnecessary unlikely()
2018-12-07blkcg: associate writeback bios with a blkgDennis Zhou
One of the goals of this series is to remove a separate reference to the css of the bio. This can and should be accessed via bio_blkcg(). In this patch, wbc_init_bio() now requires a bio to have a device associated with it. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-13cpuset: Minor cgroup2 interface updatesTejun Heo
* Rename the partition file from "cpuset.sched.partition" to "cpuset.cpus.partition". * When writing to the partition file, drop "0" and "1" and only accept "member" and "root". Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Waiman Long <longman@redhat.com>
2018-11-08cpuset: Add documentation about the new "cpuset.sched.partition" flagWaiman Long
The cgroup-v2.rst file is updated to document the purpose of the new "cpuset.sched.partition" flag and how its usage. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2018-11-08cpuset: Expose cpus.effective and mems.effective on cgroup v2 rootWaiman Long
Because of the fact that setting the "cpuset.sched.partition" in a direct child of root can remove CPUs from the root's effective CPU list, it makes sense to know what CPUs are left in the root cgroup for scheduling purpose. So the "cpuset.cpus.effective" control file is now exposed in the v2 cgroup root. For consistency, the "cpuset.mems.effective" control file is exposed as well. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2018-11-08cpuset: Enable cpuset controller in default hierarchyWaiman Long
Given the fact that thread mode had been merged into 4.14, it is now time to enable cpuset to be used in the default hierarchy (cgroup v2) as it is clearly threaded. The cpuset controller had experienced feature creep since its introduction more than a decade ago. Besides the core cpus and mems control files to limit cpus and memory nodes, there are a bunch of additional features that can be controlled from the userspace. Some of the features are of doubtful usefulness and may not be actively used. This patch enables cpuset controller in the default hierarchy with a minimal set of features, namely just the cpus and mems and their effective_* counterparts. We can certainly add more features to the default hierarchy in the future if there is a real user need for them later on. Alternatively, with the unified hiearachy, it may make more sense to move some of those additional cpuset features, if desired, to memory controller or may be to the cpu controller instead of staying with cpuset. Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2018-11-02Merge tag 'for-linus-20181102' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "The biggest part of this pull request is the revert of the blkcg cleanup series. It had one fix earlier for a stacked device issue, but another one was reported. Rather than play whack-a-mole with this, revert the entire series and try again for the next kernel release. Apart from that, only small fixes/changes. Summary: - Indentation fixup for mtip32xx (Colin Ian King) - The blkcg cleanup series revert (Dennis Zhou) - Two NVMe fixes. One fixing a regression in the nvme request initialization in this merge window, causing nvme-fc to not work. The other is a suspend/resume p2p resource issue (James, Keith) - Fix sg discard merge, allowing us to merge in cases where we didn't before (Jianchao Wang) - Call rq_qos_exit() after the queue is frozen, preventing a hang (Ming) - Fix brd queue setup, fixing an oops if we fail setting up all devices (Ming)" * tag 'for-linus-20181102' of git://git.kernel.dk/linux-block: nvme-pci: fix conflicting p2p resource adds nvme-fc: fix request private initialization blkcg: revert blkcg cleanups series block: brd: associate with queue until adding disk block: call rq_qos_exit() after queue is frozen mtip32xx: clean an indentation issue, remove extraneous tabs block: fix the DISCARD request merge
2018-11-01blkcg: revert blkcg cleanups seriesDennis Zhou
This reverts a series committed earlier due to null pointer exception bug report in [1]. It seems there are edge case interactions that I did not consider and will need some time to understand what causes the adverse interactions. The original series can be found in [2] with a follow up series in [3]. [1] https://www.spinics.net/lists/cgroups/msg20719.html [2] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/ [3] https://lore.kernel.org/lkml/20181020185612.51587-1-dennis@kernel.org/ This reverts the following commits: d459d853c2ed, b2c3fa546705, 101246ec02b5, b3b9f24f5fcc, e2b0989954ae, f0fcb3ec89f3, c839e7a03f92, bdc2491708c4, 74b7c02a9bc1, 5bf9a1f3b4ef, a7b39b4e961c, 07b05bcc3213, 49f4c2dc2b50, 27e6fa996c53 Signed-off-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-26mm: don't raise MEMCG_OOM event due to failed high-order allocationRoman Gushchin
It was reported that on some of our machines containers were restarted with OOM symptoms without an obvious reason. Despite there were almost no memory pressure and plenty of page cache, MEMCG_OOM event was raised occasionally, causing the container management software to think, that OOM has happened. However, no tasks have been killed. The following investigation showed that the problem is caused by a failing attempt to charge a high-order page. In such case, the OOM killer is never invoked. As shown below, it can happen under conditions, which are very far from a real OOM: e.g. there is plenty of clean page cache and no memory pressure. There is no sense in raising an OOM event in this case, as it might confuse a user and lead to wrong and excessive actions (e.g. restart the workload, as in my case). Let's look at the charging path in try_charge(). If the memory usage is about memory.max, which is absolutely natural for most memory cgroups, we try to reclaim some pages. Even if we were able to reclaim enough memory for the allocation, the following check can fail due to a race with another concurrent allocation: if (mem_cgroup_margin(mem_over_limit) >= nr_pages) goto retry; For regular pages the following condition will save us from triggering the OOM: if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER)) goto retry; But for high-order allocation this condition will intentionally fail. The reason behind is that we'll likely fall to regular pages anyway, so it's ok and even preferred to return ENOMEM. In this case the idea of raising MEMCG_OOM looks dubious. Fix this by moving MEMCG_OOM raising to mem_cgroup_oom() after allocation order check, so that the event won't be raised for high order allocations. This change doesn't affect regular pages allocation and charging. Link: http://lkml.kernel.org/r/20181004214050.7417-1-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26psi: cgroup supportJohannes Weiner
On a system that executes multiple cgrouped jobs and independent workloads, we don't just care about the health of the overall system, but also that of individual jobs, so that we can ensure individual job health, fairness between jobs, or prioritize some jobs over others. This patch implements pressure stall tracking for cgroups. In kernels with CONFIG_PSI=y, cgroup2 groups will have cpu.pressure, memory.pressure, and io.pressure files that track aggregate pressure stall times for only the tasks inside the cgroup. Link: http://lkml.kernel.org/r/20180828172258.3185-10-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Drake <drake@endlessm.com> Tested-by: Suren Baghdasaryan <surenb@google.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-09-21blkcg: associate writeback bios with a blkgDennis Zhou (Facebook)
One of the goals of this series is to remove a separate reference to the css of the bio. This can and should be accessed via bio_blkcg. In this patch, the wbc_init_bio call is changed such that it must be called after a queue has been associated with the bio. Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-22mm, oom: introduce memory.oom.groupRoman Gushchin
For some workloads an intervention from the OOM killer can be painful. Killing a random task can bring the workload into an inconsistent state. Historically, there are two common solutions for this problem: 1) enabling panic_on_oom, 2) using a userspace daemon to monitor OOMs and kill all outstanding processes. Both approaches have their downsides: rebooting on each OOM is an obvious waste of capacity, and handling all in userspace is tricky and requires a userspace agent, which will monitor all cgroups for OOMs. In most cases an in-kernel after-OOM cleaning-up mechanism can eliminate the necessity of enabling panic_on_oom. Also, it can simplify the cgroup management for userspace applications. This commit introduces a new knob for cgroup v2 memory controller: memory.oom.group. The knob determines whether the cgroup should be treated as an indivisible workload by the OOM killer. If set, all tasks belonging to the cgroup or to its descendants (if the memory cgroup is not a leaf cgroup) are killed together or not at all. To determine which cgroup has to be killed, we do traverse the cgroup hierarchy from the victim task's cgroup up to the OOMing cgroup (or root) and looking for the highest-level cgroup with memory.oom.group set. Tasks with the OOM protection (oom_score_adj set to -1000) are treated as an exception and are never killed. This patch doesn't change the OOM victim selection algorithm. Link: http://lkml.kernel.org/r/20180802003201.817-4-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-02block: make iolatency avg_lat exponentially decayDennis Zhou (Facebook)
Currently, avg_lat is calculated by accumulating the mean of every window in a long running cumulative average. As time goes on, the metric becomes less and less useful due to the accumulated history. This patch reuses the same calculation done in load averages to make the avg_lat metric more lively. Unlike load averages, the avg only advances when a window elapses (due to an io). Idle periods extend the most recent window. Bucketing is used to limit the history of avg_lat by binding it to the window size. So, the window range for 1/exp (decay rate) is [1 min, 2.5 min) when windows elapse immediately. The current sample window size is exposed in the debug info to enable calculation of the window range. Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-18blkcg: Track DISCARD statistics and output them in cgroup io.statTejun Heo
Add tracking of REQ_OP_DISCARD ios to the per-cgroup io.stat. Two fields, dbytes and dios, to respectively count the total bytes and number of discards are added. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andy Newell <newella@fb.com> Cc: Michael Callahan <michaelcallahan@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09Documentation: add a doc for blk-iolatencyJosef Bacik
A basic documentation to describe the interface, statistics, and behavior of io.latency. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-07mm: memcg: allow lowering memory.swap.max below the current usageTejun Heo
Currently an attempt to set swap.max into a value lower than the actual swap usage fails, which causes configuration problems as there's no way of lowering the configuration below the current usage short of turning off swap entirely. This makes swap.max difficult to use and allows delegatees to lock the delegator out of reducing swap allocation. This patch updates swap_max_write() so that the limit can be lowered below the current usage. It doesn't implement active reclaiming of swap entries for the following reasons. * mem_cgroup_swap_full() already tells the swap machinary to aggressively reclaim swap entries if the usage is above 50% of limit, so simply lowering the limit automatically triggers gradual reclaim. * Forcing back swapped out pages is likely to heavily impact the workload and mess up the working set. Given that swap usually is a lot less valuable and less scarce, letting the existing usage dissipate over time through the above gradual reclaim and as they're falted back in is likely the better behavior. Link: http://lkml.kernel.org/r/20180523185041.GR1718769@devbig577.frc2.facebook.com Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Shaohua Li <shli@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07memcg: introduce memory.minRoman Gushchin
Memory controller implements the memory.low best-effort memory protection mechanism, which works perfectly in many cases and allows protecting working sets of important workloads from sudden reclaim. But its semantics has a significant limitation: it works only as long as there is a supply of reclaimable memory. This makes it pretty useless against any sort of slow memory leaks or memory usage increases. This is especially true for swapless systems. If swap is enabled, memory soft protection effectively postpones problems, allowing a leaking application to fill all swap area, which makes no sense. The only effective way to guarantee the memory protection in this case is to invoke the OOM killer. It's possible to handle this case in userspace by reacting on MEMCG_LOW events; but there is still a place for a fail-safe in-kernel mechanism to provide stronger guarantees. This patch introduces the memory.min interface for cgroup v2 memory controller. It works very similarly to memory.low (sharing the same hierarchical behavior), except that it's not disabled if there is no more reclaimable memory in the system. If cgroup is not populated, its memory.min is ignored, because otherwise even the OOM killer wouldn't be able to reclaim the protected memory, and the system can stall. [guro@fb.com: s/low/min/ in docs] Link: http://lkml.kernel.org/r/20180510130758.GA9129@castle.DHCP.thefacebook.com Link: http://lkml.kernel.org/r/20180509180734.GA4856@castle.DHCP.thefacebook.com Signed-off-by: Roman Gushchin <guro@fb.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07mm/docs: describe memory.low refinementsRoman Gushchin
Refine cgroup v2 docs after latest memory.low changes. Link: http://lkml.kernel.org/r/20180405185921.4942-4-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-07mm, memcontrol: implement memory.swap.eventsTejun Heo
Add swap max and fail events so that userland can monitor and respond to running out of swap. I'm not too sure about the fail event. Right now, it's a bit confusing which stats / events are recursive and which aren't and also which ones reflect events which originate from a given cgroup and which targets the cgroup. No idea what the right long term solution is and it could just be that growing them organically is actually the only right thing to do. Link: http://lkml.kernel.org/r/20180416231151.GI1911913@devbig577.frc2.facebook.com Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: Rik van Riel <riel@surriel.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-05-10docs: admin-guide: add cgroup-v2 documentationMauro Carvalho Chehab
The cgroup-v2.txt is already in ReST format. So, move it to the admin-guide, where it belongs. Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>