Revision tags: v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9 |
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417dbd7b |
| 28-Dec-2023 |
Shakeel Butt <shakeelb@google.com> |
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and on further investigation, it seems like the cause is the always synchronous rstat flush in the count_shadow_nodes() added by the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats"). On further inspection it seems like we don't really need accurate stats in this function as it was already approximating the amount of appropriate shadow entries to keep for maintaining the refault information. Since there is already 2 sec periodic rstat flush, we don't need exact stats here. Let's ratelimit the rstat flush in this code path.
Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9 |
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417dbd7b |
| 28-Dec-2023 |
Shakeel Butt <shakeelb@google.com> |
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and on further investigation, it seems like the cause is the always synchronous rstat flush in the count_shadow_nodes() added by the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats"). On further inspection it seems like we don't really need accurate stats in this function as it was already approximating the amount of appropriate shadow entries to keep for maintaining the refault information. Since there is already 2 sec periodic rstat flush, we don't need exact stats here. Let's ratelimit the rstat flush in this code path.
Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9 |
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417dbd7b |
| 28-Dec-2023 |
Shakeel Butt <shakeelb@google.com> |
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and on further investigation, it seems like the cause is the always synchronous rstat flush in the count_shadow_nodes() added by the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats"). On further inspection it seems like we don't really need accurate stats in this function as it was already approximating the amount of appropriate shadow entries to keep for maintaining the refault information. Since there is already 2 sec periodic rstat flush, we don't need exact stats here. Let's ratelimit the rstat flush in this code path.
Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9 |
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417dbd7b |
| 28-Dec-2023 |
Shakeel Butt <shakeelb@google.com> |
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and on further investigation, it seems like the cause is the always synchronous rstat flush in the count_shadow_nodes() added by the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats"). On further inspection it seems like we don't really need accurate stats in this function as it was already approximating the amount of appropriate shadow entries to keep for maintaining the refault information. Since there is already 2 sec periodic rstat flush, we don't need exact stats here. Let's ratelimit the rstat flush in this code path.
Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.35, v6.6.34, v6.6.33, v6.6.32, v6.6.31, v6.6.30, v6.6.29, v6.6.28, v6.6.27, v6.6.26, v6.6.25, v6.6.24, v6.6.23, v6.6.16, v6.6.15, v6.6.14, v6.6.13, v6.6.12, v6.6.11, v6.6.10, v6.6.9 |
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417dbd7b |
| 28-Dec-2023 |
Shakeel Butt <shakeelb@google.com> |
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and
mm: ratelimit stat flush from workingset shrinker
commit d4a5b369ad6d8aae552752ff438dddde653a72ec upstream.
One of our workloads (Postgres 14 + sysbench OLTP) regressed on newer upstream kernel and on further investigation, it seems like the cause is the always synchronous rstat flush in the count_shadow_nodes() added by the commit f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats"). On further inspection it seems like we don't really need accurate stats in this function as it was already approximating the amount of appropriate shadow entries to keep for maintaining the refault information. Since there is already 2 sec periodic rstat flush, we don't need exact stats here. Let's ratelimit the rstat flush in this code path.
Link: https://lkml.kernel.org/r/20231228073055.4046430-1-shakeelb@google.com Fixes: f82e6bf9bb9b ("mm: memcg: use rstat for non-hierarchical stats") Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.8, v6.6.7, v6.6.6, v6.6.5 |
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b2ce691b |
| 08-Dec-2023 |
Yu Zhao <yuzhao@google.com> |
mm/mglru: fix underprotected page cache
commit 081488051d28d32569ebb7c7a23572778b2e7d57 upstream.
Unmapped folios accessed through file descriptors can be underprotected. Those folios are added to
mm/mglru: fix underprotected page cache
commit 081488051d28d32569ebb7c7a23572778b2e7d57 upstream.
Unmapped folios accessed through file descriptors can be underprotected. Those folios are added to the oldest generation based on:
1. The fact that they are less costly to reclaim (no need to walk the rmap and flush the TLB) and have less impact on performance (don't cause major PFs and can be non-blocking if needed again). 2. The observation that they are likely to be single-use. E.g., for client use cases like Android, its apps parse configuration files and store the data in heap (anon); for server use cases like MySQL, it reads from InnoDB files and holds the cached data for tables in buffer pools (anon).
However, the oldest generation can be very short lived, and if so, it doesn't provide the PID controller with enough time to respond to a surge of refaults. (Note that the PID controller uses weighted refaults and those from evicted generations only take a half of the whole weight.) In other words, for a short lived generation, the moving average smooths out the spike quickly.
To fix the problem: 1. For folios that are already on LRU, if they can be beyond the tracking range of tiers, i.e., five accesses through file descriptors, move them to the second oldest generation to give them more time to age. (Note that tiers are used by the PID controller to statistically determine whether folios accessed multiple times through file descriptors are worth protecting.) 2. When adding unmapped folios to LRU, adjust the placement of them so that they are not too close to the tail. The effect of this is similar to the above.
On Android, launching 55 apps sequentially: Before After Change workingset_refault_anon 25641024 25598972 0% workingset_refault_file 115016834 106178438 -8%
Link: https://lkml.kernel.org/r/20231208061407.2125867-1-yuzhao@google.com Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation") Signed-off-by: Yu Zhao <yuzhao@google.com> Reported-by: Charan Teja Kalla <quic_charante@quicinc.com> Tested-by: Kalesh Singh <kaleshsingh@google.com> Cc: T.J. Mercier <tjmercier@google.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Revision tags: v6.6.4, v6.6.3, v6.6.2, v6.5.11, v6.6.1, v6.5.10, v6.6, v6.5.9, v6.5.8, v6.5.7, v6.5.6, v6.5.5, v6.5.4, v6.5.3, v6.5.2, v6.1.51, v6.5.1, v6.1.50, v6.5, v6.1.49, v6.1.48, v6.1.46, v6.1.45, v6.1.44, v6.1.43, v6.1.42 |
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f82e6bf9 |
| 26-Jul-2023 |
Yosry Ahmed <yosryahmed@google.com> |
mm: memcg: use rstat for non-hierarchical stats
Currently, memcg uses rstat to maintain aggregated hierarchical stats. Counters are maintained for hierarchical stats at each memcg. Rstat tracks wh
mm: memcg: use rstat for non-hierarchical stats
Currently, memcg uses rstat to maintain aggregated hierarchical stats. Counters are maintained for hierarchical stats at each memcg. Rstat tracks which cgroups have updates on which cpus to keep those counters fresh on the read-side.
Non-hierarchical stats are currently not covered by rstat. Their per-cpu counters are summed up on every read, which is expensive. The original implementation did the same. At some point before rstat, non-hierarchical aggregated counters were introduced by commit a983b5ebee57 ("mm: memcontrol: fix excessive complexity in memory.stat reporting"). However, those counters were updated on the performance critical write-side, which caused regressions, so they were later removed by commit 815744d75152 ("mm: memcontrol: don't batch updates of local VM stats and events"). See [1] for more detailed history.
Kernel versions in between a983b5ebee57 & 815744d75152 (a year and a half) enjoyed cheap reads of non-hierarchical stats, specifically on cgroup v1. When moving to more recent kernels, a performance regression for reading non-hierarchical stats is observed.
Now that we have rstat, we know exactly which percpu counters have updates for each stat. We can maintain non-hierarchical counters again, making reads much more efficient, without affecting the performance critical write-side. Hence, add non-hierarchical (i.e local) counters for the stats, and extend rstat flushing to keep those up-to-date.
A caveat is that we now need a stats flush before reading local/non-hierarchical stats through {memcg/lruvec}_page_state_local() or memcg_events_local(), where we previously only needed a flush to read hierarchical stats. Most contexts reading non-hierarchical stats are already doing a flush, add a flush to the only missing context in count_shadow_nodes().
With this patch, reading memory.stat from 1000 memcgs is 3x faster on a machine with 256 cpus on cgroup v1:
# for i in $(seq 1000); do mkdir /sys/fs/cgroup/memory/cg$i; done # time cat /sys/fs/cgroup/memory/cg*/memory.stat > /dev/null real 0m0.125s user 0m0.005s sys 0m0.120s
After: real 0m0.032s user 0m0.005s sys 0m0.027s
To make sure there are no regressions on cgroup v2, I ran an artificial reclaim/refault stress test [2] that creates (NR_CPUS * 2) cgroups, assigns them limits, runs a worker process in each cgroup that allocates tmpfs memory equal to quadruple the limit (to invoke reclaim continuously), and then reads back the entire file (to invoke refaults). All workers are run in parallel, and zram is used as a swapping backend. Both reclaim and refault have conditional stats flushing. I ran this on a machine with 112 cpus, once on mm-unstable, and once on mm-unstable with this patch reverted.
(1) A few runs without this patch:
# time ./stress_reclaim_refault.sh real 0m9.949s user 0m0.496s sys 14m44.974s
# time ./stress_reclaim_refault.sh real 0m10.049s user 0m0.486s sys 14m55.791s
# time ./stress_reclaim_refault.sh real 0m9.984s user 0m0.481s sys 14m53.841s
(2) A few runs with this patch:
# time ./stress_reclaim_refault.sh real 0m9.885s user 0m0.486s sys 14m48.753s
# time ./stress_reclaim_refault.sh real 0m9.903s user 0m0.495s sys 14m48.339s
# time ./stress_reclaim_refault.sh real 0m9.861s user 0m0.507s sys 14m49.317s
No regressions are observed with this patch. There is actually a very slight improvement. If I have to guess, maybe it's because we avoid the percpu loop in count_shadow_nodes() when calling lruvec_page_state_local(), but I could not prove this using perf, it's probably in the noise.
[1] https://lore.kernel.org/lkml/20230725201811.GA1231514@cmpxchg.org/ [2] https://lore.kernel.org/lkml/CAJD7tkb17x=qwoO37uxyYXLEUVp15BQKR+Xfh7Sg9Hx-wTQ_=w@mail.gmail.com/
Link: https://lkml.kernel.org/r/20230803185046.1385770-1-yosryahmed@google.com Link: https://lkml.kernel.org/r/20230726153223.821757-2-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.41, v6.1.40, v6.1.39, v6.1.38, v6.1.37, v6.1.36, v6.4, v6.1.35, v6.1.34, v6.1.33, v6.1.32, v6.1.31, v6.1.30 |
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3af0191a |
| 23-May-2023 |
Kalesh Singh <kaleshsingh@google.com> |
Multi-gen LRU: fix workingset accounting
On Android app cycle workloads, MGLRU showed a significant reduction in workingset refaults although pgpgin/pswpin remained relatively unchanged. This indic
Multi-gen LRU: fix workingset accounting
On Android app cycle workloads, MGLRU showed a significant reduction in workingset refaults although pgpgin/pswpin remained relatively unchanged. This indicated MGLRU may be undercounting workingset refaults.
This has impact on userspace programs, like Android's LMKD, that monitor workingset refault statistics to detect thrashing.
It was found that refaults were only accounted if the MGLRU shadow entry was for a recently evicted folio. However, recently evicted folios should be accounted as workingset activation, and refaults should be accounted regardless of recency.
Fix MGLRU's workingset refault and activation accounting to more closely match that of the conventional active/inactive LRU.
Link: https://lkml.kernel.org/r/20230523205922.3852731-1-kaleshsingh@google.com Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation") Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Reported-by: Charan Teja Kalla <quic_charante@quicinc.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Cc: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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d7f1afd0 |
| 22-May-2023 |
T.J. Alumbaugh <talumbau@google.com> |
mm: multi-gen LRU: cleanup lru_gen_test_recent()
Avoid passing memcg* and pglist_data* to lru_gen_test_recent() since we only use the lruvec anyway.
Link: https://lkml.kernel.org/r/20230522112058.2
mm: multi-gen LRU: cleanup lru_gen_test_recent()
Avoid passing memcg* and pglist_data* to lru_gen_test_recent() since we only use the lruvec anyway.
Link: https://lkml.kernel.org/r/20230522112058.2965866-4-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Reviewed-by: Yuanchu Xie <yuanchu@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.29, v6.1.28 |
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ffcb5f52 |
| 02-May-2023 |
Nhat Pham <nphamcs@gmail.com> |
workingset: refactor LRU refault to expose refault recency check
Patch series "cachestat: a new syscall for page cache state of files", v13.
There is currently no good way to query the page cache s
workingset: refactor LRU refault to expose refault recency check
Patch series "cachestat: a new syscall for page cache state of files", v13.
There is currently no good way to query the page cache statistics of large files and directory trees. There is mincore(), but it scales poorly: the kernel writes out a lot of bitmap data that userspace has to aggregate, when the user really does not care about per-page information in that case. The user also needs to mmap and unmap each file as it goes along, which can be quite slow as well.
Some use cases where this information could come in handy: * Allowing database to decide whether to perform an index scan or direct table queries based on the in-memory cache state of the index. * Visibility into the writeback algorithm, for performance issues diagnostic. * Workload-aware writeback pacing: estimating IO fulfilled by page cache (and IO to be done) within a range of a file, allowing for more frequent syncing when and where there is IO capacity, and batching when there is not. * Computing memory usage of large files/directory trees, analogous to the du tool for disk usage.
More information about these use cases could be found in this thread: https://lore.kernel.org/lkml/20230315170934.GA97793@cmpxchg.org/
This series of patches introduces a new system call, cachestat, that summarizes the page cache statistics (number of cached pages, dirty pages, pages marked for writeback, evicted pages etc.) of a file, in a specified range of bytes. It also include a selftest suite that tests some typical usage. Currently, the syscall is only wired in for x86 architecture.
This interface is inspired by past discussion and concerns with fincore, which has a similar design (and as a result, issues) as mincore. Relevant links:
https://lkml.indiana.edu/hypermail/linux/kernel/1302.1/04207.html https://lkml.indiana.edu/hypermail/linux/kernel/1302.1/04209.html
I have also developed a small tool that computes the memory usage of files and directories, analogous to the du utility. User can choose between mincore or cachestat (with cachestat exporting more information than mincore). To compare the performance of these two options, I benchmarked the tool on the root directory of a Meta's server machine, each for five runs:
Using cachestat real -- Median: 33.377s, Average: 33.475s, Standard Deviation: 0.3602 user -- Median: 4.08s, Average: 4.1078s, Standard Deviation: 0.0742 sys -- Median: 28.823s, Average: 28.8866s, Standard Deviation: 0.2689
Using mincore: real -- Median: 102.352s, Average: 102.3442s, Standard Deviation: 0.2059 user -- Median: 10.149s, Average: 10.1482s, Standard Deviation: 0.0162 sys -- Median: 91.186s, Average: 91.2084s, Standard Deviation: 0.2046
I also ran both syscalls on a 2TB sparse file:
Using cachestat: real 0m0.009s user 0m0.000s sys 0m0.009s
Using mincore: real 0m37.510s user 0m2.934s sys 0m34.558s
Very large files like this are the pathological case for mincore. In fact, to compute the stats for a single 2TB file, mincore takes as long as cachestat takes to compute the stats for the entire tree! This could easily happen inadvertently when we run it on subdirectories. Mincore is clearly not suitable for a general-purpose command line tool.
Regarding security concerns, cachestat() should not pose any additional issues. The caller already has read permission to the file itself (since they need an fd to that file to call cachestat). This means that the caller can access the underlying data in its entirety, which is a much greater source of information (and as a result, a much greater security risk) than the cache status itself.
The latest API change (in v13 of the patch series) is suggested by Jens Axboe. It allows for 64-bit length argument, even on 32-bit architecture (which is previously not possible due to the limit on the number of syscall arguments). Furthermore, it eliminates the need for compatibility handling - every user can use the same ABI.
This patch (of 4):
In preparation for computing recently evicted pages in cachestat, refactor workingset_refault and lru_gen_refault to expose a helper function that would test if an evicted page is recently evicted.
[penguin-kernel@I-love.SAKURA.ne.jp: add missing rcu_read_unlock() in lru_gen_refault()] Link: https://lkml.kernel.org/r/610781bc-cf11-fc89-a46f-87cb8235d439@I-love.SAKURA.ne.jp Link: https://lkml.kernel.org/r/20230503013608.2431726-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20230503013608.2431726-2-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Brian Foster <bfoster@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.27, v6.1.26, v6.3, v6.1.25, v6.1.24 |
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#
ed8f3f99 |
| 13-Apr-2023 |
Yang Yang <yang.yang29@zte.com.cn> |
mm: workingset: update description of the source file
The calculation of workingset size is the core logic of handling refault, it had been updated several times[1][2] after workingset.c was created
mm: workingset: update description of the source file
The calculation of workingset size is the core logic of handling refault, it had been updated several times[1][2] after workingset.c was created[3]. But the description hadn't been updated accordingly, this mismatch may confuse the readers. So we update the description to make it consistent to the code.
[1] commit 34e58cac6d8f ("mm: workingset: let cache workingset challenge anon") [2] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") [3] commit a528910e12ec ("mm: thrash detection-based file cache sizing")
Link: https://lkml.kernel.org/r/202304131634494948454@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.23 |
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#
4009b2f1 |
| 30-Mar-2023 |
Yosry Ahmed <yosryahmed@google.com> |
workingset: memcg: sleep when flushing stats in workingset_refault()
In workingset_refault(), we call mem_cgroup_flush_stats_atomic_ratelimited() to read accurate stats within an RCU read section an
workingset: memcg: sleep when flushing stats in workingset_refault()
In workingset_refault(), we call mem_cgroup_flush_stats_atomic_ratelimited() to read accurate stats within an RCU read section and with sleeping disallowed. Move the call above the RCU read section to make it non-atomic.
Flushing is an expensive operation that scales with the number of cpus and the number of cgroups in the system, so avoid doing it atomically where possible.
Since workingset_refault() is the only caller of mem_cgroup_flush_stats_atomic_ratelimited(), just make it non-atomic, and rename it to mem_cgroup_flush_stats_ratelimited().
Link: https://lkml.kernel.org/r/20230330191801.1967435-7-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Vasily Averin <vasily.averin@linux.dev> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
9fad9aee |
| 30-Mar-2023 |
Yosry Ahmed <yosryahmed@google.com> |
memcg: sleep during flushing stats in safe contexts
Currently, all contexts that flush memcg stats do so with sleeping not allowed. Some of these contexts are perfectly safe to sleep in, such as re
memcg: sleep during flushing stats in safe contexts
Currently, all contexts that flush memcg stats do so with sleeping not allowed. Some of these contexts are perfectly safe to sleep in, such as reading cgroup files from userspace or the background periodic flusher. Flushing is an expensive operation that scales with the number of cpus and the number of cgroups in the system, so avoid doing it atomically where possible.
Refactor the code to make mem_cgroup_flush_stats() non-atomic (aka sleepable), and provide a separate atomic version. The atomic version is used in reclaim, refault, writeback, and in mem_cgroup_usage(). All other code paths are left to use the non-atomic version. This includes callbacks for userspace reads and the periodic flusher.
Since refault is the only caller of mem_cgroup_flush_stats_ratelimited(), change it to mem_cgroup_flush_stats_atomic_ratelimited(). Reclaim and refault code paths are modified to do non-atomic flushing in separate later patches -- so it will eventually be changed back to mem_cgroup_flush_stats_ratelimited().
Link: https://lkml.kernel.org/r/20230330191801.1967435-6-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Vasily Averin <vasily.averin@linux.dev> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
92fbbc72 |
| 30-Mar-2023 |
Yosry Ahmed <yosryahmed@google.com> |
memcg: rename mem_cgroup_flush_stats_"delayed" to "ratelimited"
mem_cgroup_flush_stats_delayed() suggests his is using a delayed_work, but this is actually sometimes flushing directly from the calls
memcg: rename mem_cgroup_flush_stats_"delayed" to "ratelimited"
mem_cgroup_flush_stats_delayed() suggests his is using a delayed_work, but this is actually sometimes flushing directly from the callsite.
What it's doing is ratelimited calls. A better name would be mem_cgroup_flush_stats_ratelimited().
Link: https://lkml.kernel.org/r/20230330191801.1967435-3-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Vasily Averin <vasily.averin@linux.dev> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.22, v6.1.21, v6.1.20, v6.1.19, v6.1.18, v6.1.17, v6.1.16, v6.1.15, v6.1.14, v6.1.13, v6.2, v6.1.12, v6.1.11, v6.1.10, v6.1.9, v6.1.8 |
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#
5649d113 |
| 18-Jan-2023 |
Yang Yang <yang.yang29@zte.com.cn> |
swap_state: update shadow_nodes for anonymous page
Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is updated when page cache add or delete since long time ago workingset only
swap_state: update shadow_nodes for anonymous page
Shadow_nodes is for shadow nodes reclaiming of workingset handling, it is updated when page cache add or delete since long time ago workingset only supported page cache. But when workingset supports anonymous page detection, we missied updating shadow nodes for it. This caused that shadow nodes of anonymous page will never be reclaimd by scan_shadow_nodes() even they use much memory and system memory is tense.
So update shadow_nodes of anonymous page when swap cache is add or delete by calling xas_set_update(..workingset_update_node).
Link: https://lkml.kernel.org/r/202301182013032211005@zte.com.cn Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.7, v6.1.6, v6.1.5, v6.0.19, v6.0.18, v6.1.4 |
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#
f78dfc7b |
| 04-Jan-2023 |
Johannes Weiner <hannes@cmpxchg.org> |
workingset: fix confusion around eviction vs refault container
Refault decisions are made based on the lruvec where the page was evicted, as that determined its LRU order while it was alive. Stats
workingset: fix confusion around eviction vs refault container
Refault decisions are made based on the lruvec where the page was evicted, as that determined its LRU order while it was alive. Stats and workingset aging must then occur on the lruvec of the new page, as that's the node and cgroup that experience the refault and that's the lruvec whose nonresident info ages out by a new resident page. Those lruvecs could be different when a page is shared between cgroups, or the refaulting page is allocated on a different node.
There are currently two mix-ups:
1. When swap is available, the resident anon set must be considered when comparing the refault distance. The comparison is made against the right anon set, but the check for swap is not. When pages get evicted from a cgroup with swap, and refault in one without, this can incorrectly consider a hot refault as cold - and vice versa. Fix that by using the eviction cgroup for the swap check.
2. The stats and workingset age are updated against the wrong lruvec altogether: the right cgroup but the wrong NUMA node. When a page refaults on a different NUMA node, this will have confusing stats and distort the workingset age on a different lruvec - again possibly resulting in hot/cold misclassifications down the line.
Fix the swap check and the refault pgdat to address both concerns.
This was found during code review. It hasn't caused notable issues in production, suggesting that those refault-migrations are relatively rare in practice.
Link: https://lkml.kernel.org/r/20230104222944.2380117-1-nphamcs@gmail.com Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Co-developed-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.3, v6.0.17, v6.1.2, v6.0.16 |
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#
391655fe |
| 21-Dec-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: rename lru_gen_struct to lru_gen_folio
Patch series "mm: multi-gen LRU: memcg LRU", v3.
Overview ========
An memcg LRU is a per-node LRU of memcgs. It is also an LRU of LRUs, s
mm: multi-gen LRU: rename lru_gen_struct to lru_gen_folio
Patch series "mm: multi-gen LRU: memcg LRU", v3.
Overview ========
An memcg LRU is a per-node LRU of memcgs. It is also an LRU of LRUs, since each node and memcg combination has an LRU of folios (see mem_cgroup_lruvec()).
Its goal is to improve the scalability of global reclaim, which is critical to system-wide memory overcommit in data centers. Note that memcg reclaim is currently out of scope.
Its memory bloat is a pointer to each lruvec and negligible to each pglist_data. In terms of traversing memcgs during global reclaim, it improves the best-case complexity from O(n) to O(1) and does not affect the worst-case complexity O(n). Therefore, on average, it has a sublinear complexity in contrast to the current linear complexity.
The basic structure of an memcg LRU can be understood by an analogy to the active/inactive LRU (of folios): 1. It has the young and the old (generations), i.e., the counterparts to the active and the inactive; 2. The increment of max_seq triggers promotion, i.e., the counterpart to activation; 3. Other events trigger similar operations, e.g., offlining an memcg triggers demotion, i.e., the counterpart to deactivation.
In terms of global reclaim, it has two distinct features: 1. Sharding, which allows each thread to start at a random memcg (in the old generation) and improves parallelism; 2. Eventual fairness, which allows direct reclaim to bail out at will and reduces latency without affecting fairness over some time.
The commit message in patch 6 details the workflow: https://lore.kernel.org/r/20221222041905.2431096-7-yuzhao@google.com/
The following is a simple test to quickly verify its effectiveness.
Test design: 1. Create multiple memcgs. 2. Each memcg contains a job (fio). 3. All jobs access the same amount of memory randomly. 4. The system does not experience global memory pressure. 5. Periodically write to the root memory.reclaim.
Desired outcome: 1. All memcgs have similar pgsteal counts, i.e., stddev(pgsteal) over mean(pgsteal) is close to 0%. 2. The total pgsteal is close to the total requested through memory.reclaim, i.e., sum(pgsteal) over sum(requested) is close to 100%.
Actual outcome [1]: MGLRU off MGLRU on stddev(pgsteal) / mean(pgsteal) 75% 20% sum(pgsteal) / sum(requested) 425% 95%
#################################################################### MEMCGS=128
for ((memcg = 0; memcg < $MEMCGS; memcg++)); do mkdir /sys/fs/cgroup/memcg$memcg done
start() { echo $BASHPID > /sys/fs/cgroup/memcg$memcg/cgroup.procs
fio -name=memcg$memcg --numjobs=1 --ioengine=mmap \ --filename=/dev/zero --size=1920M --rw=randrw \ --rate=64m,64m --random_distribution=random \ --fadvise_hint=0 --time_based --runtime=10h \ --group_reporting --minimal }
for ((memcg = 0; memcg < $MEMCGS; memcg++)); do start & done
sleep 600
for ((i = 0; i < 600; i++)); do echo 256m >/sys/fs/cgroup/memory.reclaim sleep 6 done
for ((memcg = 0; memcg < $MEMCGS; memcg++)); do grep "pgsteal " /sys/fs/cgroup/memcg$memcg/memory.stat done ####################################################################
[1]: This was obtained from running the above script (touches less than 256GB memory) on an EPYC 7B13 with 512GB DRAM for over an hour.
This patch (of 8):
The new name lru_gen_folio will be more distinct from the coming lru_gen_memcg.
Link: https://lkml.kernel.org/r/20221222041905.2431096-1-yuzhao@google.com Link: https://lkml.kernel.org/r/20221222041905.2431096-2-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v6.1.1, v6.0.15, v6.0.14, v6.0.13, v6.1, v6.0.12, v6.0.11, v6.0.10, v5.15.80, v6.0.9, v5.15.79, v6.0.8, v5.15.78, v6.0.7, v5.15.77 |
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#
6e1ca48d |
| 01-Nov-2022 |
Vishal Moola (Oracle) <vishal.moola@gmail.com> |
folio-compat: remove lru_cache_add()
There are no longer any callers of lru_cache_add(), so remove it. This saves 79 bytes of kernel text. Also cleanup some comments such that they reference the n
folio-compat: remove lru_cache_add()
There are no longer any callers of lru_cache_add(), so remove it. This saves 79 bytes of kernel text. Also cleanup some comments such that they reference the new folio_add_lru() instead.
Link: https://lkml.kernel.org/r/20221101175326.13265-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v5.15.76, v6.0.6, v6.0.5, v5.15.75, v6.0.4, v6.0.3, v6.0.2, v5.15.74 |
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#
0538a82c |
| 13-Oct-2022 |
Johannes Weiner <hannes@cmpxchg.org> |
mm: vmscan: make rotations a secondary factor in balancing anon vs file
We noticed a 2% webserver throughput regression after upgrading from 5.6. This could be tracked down to a shift in the anon/f
mm: vmscan: make rotations a secondary factor in balancing anon vs file
We noticed a 2% webserver throughput regression after upgrading from 5.6. This could be tracked down to a shift in the anon/file reclaim balance (confirmed with swappiness) that resulted in worse reclaim efficiency and thus more kswapd activity for the same outcome.
The change that exposed the problem is aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU"). By qualifying swapins based on their refault distance, it lowered the cost of anon reclaim in this workload, in turn causing (much) more anon scanning than before. Scanning the anon list is more expensive due to the higher ratio of mmapped pages that may rotate during reclaim, and so the result was an increase in %sys time.
Right now, rotations aren't considered a cost when balancing scan pressure between LRUs. We can end up with very few file refaults putting all the scan pressure on hot anon pages that are rotated en masse, don't get reclaimed, and never push back on the file LRU again. We still only reclaim file cache in that case, but we burn a lot CPU rotating anon pages. It's "fair" from an LRU age POV, but doesn't reflect the real cost it imposes on the system.
Consider rotations as a secondary factor in balancing the LRUs. This doesn't attempt to make a precise comparison between IO cost and CPU cost, it just says: if reloads are about comparable between the lists, or rotations are overwhelmingly different, adjust for CPU work.
This fixed the regression on our webservers. It has since been deployed to the entire Meta fleet and hasn't caused any problems.
Link: https://lkml.kernel.org/r/20221013193113.726425-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v5.15.73, v6.0.1, v5.15.72, v6.0, v5.15.71, v5.15.70, v5.15.69 |
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#
ac35a490 |
| 18-Sep-2022 |
Yu Zhao <yuzhao@google.com> |
mm: multi-gen LRU: minimal implementation
To avoid confusion, the terms "promotion" and "demotion" will be applied to the multi-gen LRU, as a new convention; the terms "activation" and "deactivation
mm: multi-gen LRU: minimal implementation
To avoid confusion, the terms "promotion" and "demotion" will be applied to the multi-gen LRU, as a new convention; the terms "activation" and "deactivation" will be applied to the active/inactive LRU, as usual.
The aging produces young generations. Given an lruvec, it increments max_seq when max_seq-min_seq+1 approaches MIN_NR_GENS. The aging promotes hot pages to the youngest generation when it finds them accessed through page tables; the demotion of cold pages happens consequently when it increments max_seq. Promotion in the aging path does not involve any LRU list operations, only the updates of the gen counter and lrugen->nr_pages[]; demotion, unless as the result of the increment of max_seq, requires LRU list operations, e.g., lru_deactivate_fn(). The aging has the complexity O(nr_hot_pages), since it is only interested in hot pages.
The eviction consumes old generations. Given an lruvec, it increments min_seq when lrugen->lists[] indexed by min_seq%MAX_NR_GENS becomes empty. A feedback loop modeled after the PID controller monitors refaults over anon and file types and decides which type to evict when both types are available from the same generation.
The protection of pages accessed multiple times through file descriptors takes place in the eviction path. Each generation is divided into multiple tiers. A page accessed N times through file descriptors is in tier order_base_2(N). Tiers do not have dedicated lrugen->lists[], only bits in folio->flags. The aforementioned feedback loop also monitors refaults over all tiers and decides when to protect pages in which tiers (N>1), using the first tier (N=0,1) as a baseline. The first tier contains single-use unmapped clean pages, which are most likely the best choices. In contrast to promotion in the aging path, the protection of a page in the eviction path is achieved by moving this page to the next generation, i.e., min_seq+1, if the feedback loop decides so. This approach has the following advantages:
1. It removes the cost of activation in the buffered access path by inferring whether pages accessed multiple times through file descriptors are statistically hot and thus worth protecting in the eviction path. 2. It takes pages accessed through page tables into account and avoids overprotecting pages accessed multiple times through file descriptors. (Pages accessed through page tables are in the first tier, since N=0.) 3. More tiers provide better protection for pages accessed more than twice through file descriptors, when under heavy buffered I/O workloads.
Server benchmark results: Single workload: fio (buffered I/O): +[30, 32]% IOPS BW 5.19-rc1: 2673k 10.2GiB/s patch1-6: 3491k 13.3GiB/s
Single workload: memcached (anon): -[4, 6]% Ops/sec KB/sec 5.19-rc1: 1161501.04 45177.25 patch1-6: 1106168.46 43025.04
Configurations: CPU: two Xeon 6154 Mem: total 256G
Node 1 was only used as a ram disk to reduce the variance in the results.
patch drivers/block/brd.c <<EOF 99,100c99,100 < gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM; < page = alloc_page(gfp_flags); --- > gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM | __GFP_THISNODE; > page = alloc_pages_node(1, gfp_flags, 0); EOF
cat >>/etc/systemd/system.conf <<EOF CPUAffinity=numa NUMAPolicy=bind NUMAMask=0 EOF
cat >>/etc/memcached.conf <<EOF -m 184320 -s /var/run/memcached/memcached.sock -a 0766 -t 36 -B binary EOF
cat fio.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkfs.ext4 /dev/ram0 mount -t ext4 /dev/ram0 /mnt
mkdir /sys/fs/cgroup/user.slice/test echo 38654705664 >/sys/fs/cgroup/user.slice/test/memory.max echo $$ >/sys/fs/cgroup/user.slice/test/cgroup.procs fio -name=mglru --numjobs=72 --directory=/mnt --size=1408m \ --buffered=1 --ioengine=io_uring --iodepth=128 \ --iodepth_batch_submit=32 --iodepth_batch_complete=32 \ --rw=randread --random_distribution=random --norandommap \ --time_based --ramp_time=10m --runtime=5m --group_reporting
cat memcached.sh modprobe brd rd_nr=1 rd_size=113246208 swapoff -a mkswap /dev/ram0 swapon /dev/ram0
memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=P:P -c 1 -t 36 \ --ratio 1:0 --pipeline 8 -d 2000
memtier_benchmark -S /var/run/memcached/memcached.sock \ -P memcache_binary -n allkeys --key-minimum=1 \ --key-maximum=65000000 --key-pattern=R:R -c 1 -t 36 \ --ratio 0:1 --pipeline 8 --randomize --distinct-client-seed
Client benchmark results: kswapd profiles: 5.19-rc1 40.33% page_vma_mapped_walk (overhead) 21.80% lzo1x_1_do_compress (real work) 7.53% do_raw_spin_lock 3.95% _raw_spin_unlock_irq 2.52% vma_interval_tree_iter_next 2.37% folio_referenced_one 2.28% vma_interval_tree_subtree_search 1.97% anon_vma_interval_tree_iter_first 1.60% ptep_clear_flush 1.06% __zram_bvec_write
patch1-6 39.03% lzo1x_1_do_compress (real work) 18.47% page_vma_mapped_walk (overhead) 6.74% _raw_spin_unlock_irq 3.97% do_raw_spin_lock 2.49% ptep_clear_flush 2.48% anon_vma_interval_tree_iter_first 1.92% folio_referenced_one 1.88% __zram_bvec_write 1.48% memmove 1.31% vma_interval_tree_iter_next
Configurations: CPU: single Snapdragon 7c Mem: total 4G
ChromeOS MemoryPressure [1]
[1] https://chromium.googlesource.com/chromiumos/platform/tast-tests/
Link: https://lkml.kernel.org/r/20220918080010.2920238-7-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v5.15.68, v5.15.67, v5.15.66, v5.15.65, v5.15.64, v5.15.63, v5.15.62, v5.15.61, v5.15.60, v5.15.59, v5.19, v5.15.58, v5.15.57, v5.15.56, v5.15.55, v5.15.54, v5.15.53, v5.15.52, v5.15.51, v5.15.50, v5.15.49, v5.15.48, v5.15.47, v5.15.46, v5.15.45 |
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e33c267a |
| 31-May-2022 |
Roman Gushchin <roman.gushchin@linux.dev> |
mm: shrinkers: provide shrinkers with names
Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g.
mm: shrinkers: provide shrinkers with names
Currently shrinkers are anonymous objects. For debugging purposes they can be identified by count/scan function names, but it's not always useful: e.g. for superblock's shrinkers it's nice to have at least an idea of to which superblock the shrinker belongs.
This commit adds names to shrinkers. register_shrinker() and prealloc_shrinker() functions are extended to take a format and arguments to master a name.
In some cases it's not possible to determine a good name at the time when a shrinker is allocated. For such cases shrinker_debugfs_rename() is provided.
The expected format is: <subsystem>-<shrinker_type>[:<instance>]-<id> For some shrinkers an instance can be encoded as (MAJOR:MINOR) pair.
After this change the shrinker debugfs directory looks like: $ cd /sys/kernel/debug/shrinker/ $ ls dquota-cache-16 sb-devpts-28 sb-proc-47 sb-tmpfs-42 mm-shadow-18 sb-devtmpfs-5 sb-proc-48 sb-tmpfs-43 mm-zspool:zram0-34 sb-hugetlbfs-17 sb-pstore-31 sb-tmpfs-44 rcu-kfree-0 sb-hugetlbfs-33 sb-rootfs-2 sb-tmpfs-49 sb-aio-20 sb-iomem-12 sb-securityfs-6 sb-tracefs-13 sb-anon_inodefs-15 sb-mqueue-21 sb-selinuxfs-22 sb-xfs:vda1-36 sb-bdev-3 sb-nsfs-4 sb-sockfs-8 sb-zsmalloc-19 sb-bpf-32 sb-pipefs-14 sb-sysfs-26 thp-deferred_split-10 sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-1 thp-zero-9 sb-cgroup2-30 sb-proc-39 sb-tmpfs-27 xfs-buf:vda1-37 sb-configfs-23 sb-proc-41 sb-tmpfs-29 xfs-inodegc:vda1-38 sb-dax-11 sb-proc-45 sb-tmpfs-35 sb-debugfs-7 sb-proc-46 sb-tmpfs-40
[roman.gushchin@linux.dev: fix build warnings] Link: https://lkml.kernel.org/r/Yr+ZTnLb9lJk6fJO@castle Reported-by: kernel test robot <lkp@intel.com> Link: https://lkml.kernel.org/r/20220601032227.4076670-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Cc: Dave Chinner <dchinner@redhat.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Revision tags: v5.15.44, v5.15.43, v5.15.42, v5.18, v5.15.41, v5.15.40, v5.15.39, v5.15.38, v5.15.37, v5.15.36 |
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9b301615 |
| 21-Apr-2022 |
Shakeel Butt <shakeelb@google.com> |
memcg: sync flush only if periodic flush is delayed
Daniel Dao has reported [1] a regression on workloads that may trigger a lot of refaults (anon and file). The underlying issue is that flushing r
memcg: sync flush only if periodic flush is delayed
Daniel Dao has reported [1] a regression on workloads that may trigger a lot of refaults (anon and file). The underlying issue is that flushing rstat is expensive. Although rstat flush are batched with (nr_cpus * MEMCG_BATCH) stat updates, it seems like there are workloads which genuinely do stat updates larger than batch value within short amount of time. Since the rstat flush can happen in the performance critical codepaths like page faults, such workload can suffer greatly.
This patch fixes this regression by making the rstat flushing conditional in the performance critical codepaths. More specifically, the kernel relies on the async periodic rstat flusher to flush the stats and only if the periodic flusher is delayed by more than twice the amount of its normal time window then the kernel allows rstat flushing from the performance critical codepaths.
Now the question: what are the side-effects of this change? The worst that can happen is the refault codepath will see 4sec old lruvec stats and may cause false (or missed) activations of the refaulted page which may under-or-overestimate the workingset size. Though that is not very concerning as the kernel can already miss or do false activations.
There are two more codepaths whose flushing behavior is not changed by this patch and we may need to come to them in future. One is the writeback stats used by dirty throttling and second is the deactivation heuristic in the reclaim. For now keeping an eye on them and if there is report of regression due to these codepaths, we will reevaluate then.
Link: https://lore.kernel.org/all/CA+wXwBSyO87ZX5PVwdHm-=dBjZYECGmfnydUicUyrQqndgX2MQ@mail.gmail.com [1] Link: https://lkml.kernel.org/r/20220304184040.1304781-1-shakeelb@google.com Fixes: 1f828223b799 ("memcg: flush lruvec stats in the refault") Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: Daniel Dao <dqminh@cloudflare.com> Tested-by: Ivan Babrou <ivan@cloudflare.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Frank Hofmann <fhofmann@cloudflare.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Revision tags: v5.15.35, v5.15.34, v5.15.33, v5.15.32, v5.15.31 |
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2386eef2 |
| 22-Mar-2022 |
Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
mm: workingset: replace IRQ-off check with a lockdep assert.
Commit 68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow nodes") introduced an IRQ-off check to ensure that a lock is held wh
mm: workingset: replace IRQ-off check with a lockdep assert.
Commit 68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow nodes") introduced an IRQ-off check to ensure that a lock is held which also disabled interrupts. This does not work the same way on PREEMPT_RT because none of the locks, that are held, disable interrupts.
Replace this check with a lockdep assert which ensures that the lock is held.
Link: https://lkml.kernel.org/r/20220301122143.1521823-3-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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9bbdc0f3 |
| 22-Mar-2022 |
Muchun Song <songmuchun@bytedance.com> |
xarray: use kmem_cache_alloc_lru to allocate xa_node
The workingset will add the xa_node to the shadow_nodes list. So the allocation of xa_node should be done by kmem_cache_alloc_lru(). Using xas_
xarray: use kmem_cache_alloc_lru to allocate xa_node
The workingset will add the xa_node to the shadow_nodes list. So the allocation of xa_node should be done by kmem_cache_alloc_lru(). Using xas_set_lru() to pass the list_lru which we want to insert xa_node into to set up the xa_node reclaim context correctly.
Link: https://lkml.kernel.org/r/20220228122126.37293-9-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Alex Shi <alexs@kernel.org> Cc: Anna Schumaker <Anna.Schumaker@Netapp.com> Cc: Chao Yu <chao@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Kari Argillander <kari.argillander@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Revision tags: v5.17, v5.15.30, v5.15.29, v5.15.28, v5.15.27, v5.15.26, v5.15.25, v5.15.24, v5.15.23, v5.15.22, v5.15.21, v5.15.20, v5.15.19, v5.15.18, v5.15.17, v5.4.173, v5.15.16, v5.15.15, v5.16 |
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8927f647 |
| 23-Dec-2021 |
Matthew Wilcox (Oracle) <willy@infradead.org> |
mm/workingset: Convert workingset_eviction() to take a folio
This removes an assumption that THPs are the only kind of compound pages and removes a few hidden calls to compound_head().
Signed-off-b
mm/workingset: Convert workingset_eviction() to take a folio
This removes an assumption that THPs are the only kind of compound pages and removes a few hidden calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
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