mm: memcontrol: clarify swapaccount=0 deprecation warning

commit 118642d7f606fc9b9c92ee611275420320290ffb upstream.

The swapaccount deprecation warning is throwing false positives. Since we
deprec

mm: memcontrol: clarify swapaccount=0 deprecation warning

commit 118642d7f606fc9b9c92ee611275420320290ffb upstream.

The swapaccount deprecation warning is throwing false positives. Since we
deprecated the knob and defaulted to enabling, the only reports we've been
getting are from folks that set swapaccount=1. While this is a nice
affirmation that always-enabling was the right choice, we certainly don't
want to warn when users request the supported mode.

Only warn when disabling is requested, and clarify the warning.

[colin.i.king@gmail.com: spelling: "commdandline" -> "commandline"]
Link: https://lkml.kernel.org/r/20240215090544.1649201-1-colin.i.king@gmail.com
Link: https://lkml.kernel.org/r/20240213081634.3652326-1-hannes@cmpxchg.org
Fixes: b25806dcd3d5 ("mm: memcontrol: deprecate swapaccounting=0 mode")
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reported-by: "Jonas Schäfer" <jonas@wielicki.name>
Reported-by: Narcis Garcia <debianlists@actiu.net>
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors

commit 24948e3b7b12e0031a6edb4f49bbb9fb2ad1e4e9 upstream.

Objcg vectors attached to slab pages to store slab object ownership
information a

mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors

commit 24948e3b7b12e0031a6edb4f49bbb9fb2ad1e4e9 upstream.

Objcg vectors attached to slab pages to store slab object ownership
information are allocated using gfp flags for the original slab
allocation. Depending on slab page order and the size of slab objects,
objcg vector can take several pages.

If the original allocation was done with the __GFP_NOFAIL flag, it
triggered a warning in the page allocation code. Indeed, order > 1 pages
should not been allocated with the __GFP_NOFAIL flag.

Fix this by simply dropping the __GFP_NOFAIL flag when allocating the
objcg vector. It effectively allows to skip the accounting of a single
slab object under a heavy memory pressure.

An alternative would be to implement the mechanism to fallback to order-0
allocations for accounting metadata, which is also not perfect because it
will increase performance penalty and memory footprint of the kernel
memory accounting under memory pressure.

Link: https://lkml.kernel.org/r/ZUp8ZFGxwmCx4ZFr@P9FQF9L96D.corp.robot.car
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reported-by: Christoph Lameter <cl@linux.com>
Closes: https://lkml.kernel.org/r/6b42243e-f197-600a-5d22-56bd728a5ad8@gentwo.org
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

mm, memcg: reconsider kmem.limit_in_bytes deprecation

This reverts commits 86327e8eb94c ("memcg: drop kmem.limit_in_bytes") and
partially reverts 58056f77502f ("memcg, kmem: further deprecate
kmem.l

mm, memcg: reconsider kmem.limit_in_bytes deprecation

This reverts commits 86327e8eb94c ("memcg: drop kmem.limit_in_bytes") and
partially reverts 58056f77502f ("memcg, kmem: further deprecate
kmem.limit_in_bytes") which have incrementally removed support for the
kernel memory accounting hard limit. Unfortunately it has turned out that
there is still userspace depending on the existence of
memory.kmem.limit_in_bytes [1]. The underlying functionality is not
really required but the non-existent file just confuses the userspace
which fails in the result. The patch to fix this on the userspace side
has been submitted but it is hard to predict how it will propagate through
the maze of 3rd party consumers of the software.

Now, reverting alone 86327e8eb94c is not an option because there is
another set of userspace which cannot cope with ENOTSUPP returned when
writing to the file. Therefore we have to go and revisit 58056f77502f as
well. There are two ways to go ahead. Either we give up on the
deprecation and fully revert 58056f77502f as well or we can keep
kmem.limit_in_bytes but make the write a noop and warn about the fact.
This should work for both known breaking workloads which depend on the
existence but do not depend on the hard limit enforcement.

Note to backporters to stable trees. a8c49af3be5f ("memcg: add per-memcg
total kernel memory stat") introduced in 4.18 has added memcg_account_kmem
so the accounting is not done by obj_cgroup_charge_pages directly for v1
anymore. Prior kernels need to add it explicitly (thanks to Johannes for
pointing this out).

[akpm@linux-foundation.org: fix build - remove unused local]
Link: http://lkml.kernel.org/r/20230920081101.GA12096@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net [1]
Link: https://lkml.kernel.org/r/ZRE5VJozPZt9bRPy@dhcp22.suse.cz
Fixes: 86327e8eb94c ("memcg: drop kmem.limit_in_bytes")
Fixes: 58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement

Breno and Josef report a deadlock scenario from cgroup reclaim
re-entering the filesystem:

[ 361.546690] =========================

mm: memcontrol: fix GFP_NOFS recursion in memory.high enforcement

Breno and Josef report a deadlock scenario from cgroup reclaim
re-entering the filesystem:

[ 361.546690] ======================================================
[ 361.559210] WARNING: possible circular locking dependency detected
[ 361.571703] 6.5.0-0_fbk700_debug_rc0_kbuilder_13159_gbf787a128001 #1 Tainted: G S E
[ 361.589704] ------------------------------------------------------
[ 361.602277] find/9315 is trying to acquire lock:
[ 361.611625] ffff88837ba140c0 (&delayed_node->mutex){+.+.}-{4:4}, at: __btrfs_release_delayed_node+0x68/0x4f0
[ 361.631437]
[ 361.631437] but task is already holding lock:
[ 361.643243] ffff8881765b8678 (btrfs-tree-01){++++}-{4:4}, at: btrfs_tree_read_lock+0x1e/0x40

[ 362.904457] mutex_lock_nested+0x1c/0x30
[ 362.912414] __btrfs_release_delayed_node+0x68/0x4f0
[ 362.922460] btrfs_evict_inode+0x301/0x770
[ 362.982726] evict+0x17c/0x380
[ 362.988944] prune_icache_sb+0x100/0x1d0
[ 363.005559] super_cache_scan+0x1f8/0x260
[ 363.013695] do_shrink_slab+0x2a2/0x540
[ 363.021489] shrink_slab_memcg+0x237/0x3d0
[ 363.050606] shrink_slab+0xa7/0x240
[ 363.083382] shrink_node_memcgs+0x262/0x3b0
[ 363.091870] shrink_node+0x1a4/0x720
[ 363.099150] shrink_zones+0x1f6/0x5d0
[ 363.148798] do_try_to_free_pages+0x19b/0x5e0
[ 363.157633] try_to_free_mem_cgroup_pages+0x266/0x370
[ 363.190575] reclaim_high+0x16f/0x1f0
[ 363.208409] mem_cgroup_handle_over_high+0x10b/0x270
[ 363.246678] try_charge_memcg+0xaf2/0xc70
[ 363.304151] charge_memcg+0xf0/0x350
[ 363.320070] __mem_cgroup_charge+0x28/0x40
[ 363.328371] __filemap_add_folio+0x870/0xd50
[ 363.371303] filemap_add_folio+0xdd/0x310
[ 363.399696] __filemap_get_folio+0x2fc/0x7d0
[ 363.419086] pagecache_get_page+0xe/0x30
[ 363.427048] alloc_extent_buffer+0x1cd/0x6a0
[ 363.435704] read_tree_block+0x43/0xc0
[ 363.443316] read_block_for_search+0x361/0x510
[ 363.466690] btrfs_search_slot+0xc8c/0x1520

This is caused by the mem_cgroup_handle_over_high() not respecting the
gfp_mask of the allocation context. We used to only call this function on
resume to userspace, where no locks were held. But c9afe31ec443 ("memcg:
synchronously enforce memory.high for large overcharges") added a call
from the allocation context without considering the gfp.

Link: https://lkml.kernel.org/r/20230914152139.100822-1-hannes@cmpxchg.org
Fixes: c9afe31ec443 ("memcg: synchronously enforce memory.high for large overcharges")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Breno Leitao <leitao@debian.org>
Reported-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org> [5.17+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

memcontrol: ensure memcg acquired by id is properly set up

In the eviction recency check, we attempt to retrieve the memcg to which
the folio belonged when it was evicted, by the memcg id stored in

memcontrol: ensure memcg acquired by id is properly set up

In the eviction recency check, we attempt to retrieve the memcg to which
the folio belonged when it was evicted, by the memcg id stored in the
shadow entry. However, there is a chance that the retrieved memcg is not
the original memcg that has been killed, but a new one which happens to
have the same id.

This is a somewhat unfortunate, but acceptable and rare inaccuracy in the
heuristics. However, if we retrieve this new memcg between its allocation
and when it is properly attached to the memcg hierarchy, we could run into
the following NULL pointer exception during the memcg hierarchy traversal
done in mem_cgroup_get_nr_swap_pages():

[ 155757.793456] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 155757.807568] #PF: supervisor read access in kernel mode
[ 155757.818024] #PF: error_code(0x0000) - not-present page
[ 155757.828482] PGD 401f77067 P4D 401f77067 PUD 401f76067 PMD 0
[ 155757.839985] Oops: 0000 [#1] SMP
[ 155757.887870] RIP: 0010:mem_cgroup_get_nr_swap_pages+0x3d/0xb0
[ 155757.899377] Code: 29 19 4a 02 48 39 f9 74 63 48 8b 97 c0 00 00 00 48 8b b7 58 02 00 00 48 2b b7 c0 01 00 00 48 39 f0 48 0f 4d c6 48 39 d1 74 42 <48> 8b b2 c0 00 00 00 48 8b ba 58 02 00 00 48 2b ba c0 01 00 00 48
[ 155757.937125] RSP: 0018:ffffc9002ecdfbc8 EFLAGS: 00010286
[ 155757.947755] RAX: 00000000003a3b1c RBX: 000007ffffffffff RCX: ffff888280183000
[ 155757.962202] RDX: 0000000000000000 RSI: 0007ffffffffffff RDI: ffff888bbc2d1000
[ 155757.976648] RBP: 0000000000000001 R08: 000000000000000b R09: ffff888ad9cedba0
[ 155757.991094] R10: ffffea0039c07900 R11: 0000000000000010 R12: ffff888b23a7b000
[ 155758.005540] R13: 0000000000000000 R14: ffff888bbc2d1000 R15: 000007ffffc71354
[ 155758.019991] FS: 00007f6234c68640(0000) GS:ffff88903f9c0000(0000) knlGS:0000000000000000
[ 155758.036356] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 155758.048023] CR2: 00000000000000c0 CR3: 0000000a83eb8004 CR4: 00000000007706e0
[ 155758.062473] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 155758.076924] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 155758.091376] PKRU: 55555554
[ 155758.096957] Call Trace:
[ 155758.102016] <TASK>
[ 155758.106502] ? __die+0x78/0xc0
[ 155758.112793] ? page_fault_oops+0x286/0x380
[ 155758.121175] ? exc_page_fault+0x5d/0x110
[ 155758.129209] ? asm_exc_page_fault+0x22/0x30
[ 155758.137763] ? mem_cgroup_get_nr_swap_pages+0x3d/0xb0
[ 155758.148060] workingset_test_recent+0xda/0x1b0
[ 155758.157133] workingset_refault+0xca/0x1e0
[ 155758.165508] filemap_add_folio+0x4d/0x70
[ 155758.173538] page_cache_ra_unbounded+0xed/0x190
[ 155758.182919] page_cache_sync_ra+0xd6/0x1e0
[ 155758.191738] filemap_read+0x68d/0xdf0
[ 155758.199495] ? mlx5e_napi_poll+0x123/0x940
[ 155758.207981] ? __napi_schedule+0x55/0x90
[ 155758.216095] __x64_sys_pread64+0x1d6/0x2c0
[ 155758.224601] do_syscall_64+0x3d/0x80
[ 155758.232058] entry_SYSCALL_64_after_hwframe+0x46/0xb0
[ 155758.242473] RIP: 0033:0x7f62c29153b5
[ 155758.249938] Code: e8 48 89 75 f0 89 7d f8 48 89 4d e0 e8 b4 e6 f7 ff 41 89 c0 4c 8b 55 e0 48 8b 55 e8 48 8b 75 f0 8b 7d f8 b8 11 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 33 44 89 c7 48 89 45 f8 e8 e7 e6 f7 ff 48 8b
[ 155758.288005] RSP: 002b:00007f6234c5ffd0 EFLAGS: 00000293 ORIG_RAX: 0000000000000011
[ 155758.303474] RAX: ffffffffffffffda RBX: 00007f628c4e70c0 RCX: 00007f62c29153b5
[ 155758.318075] RDX: 000000000003c041 RSI: 00007f61d2986000 RDI: 0000000000000076
[ 155758.332678] RBP: 00007f6234c5fff0 R08: 0000000000000000 R09: 0000000064d5230c
[ 155758.347452] R10: 000000000027d450 R11: 0000000000000293 R12: 000000000003c041
[ 155758.362044] R13: 00007f61d2986000 R14: 00007f629e11b060 R15: 000000000027d450
[ 155758.376661] </TASK>

This patch fixes the issue by moving the memcg's id publication from the
alloc stage to online stage, ensuring that any memcg acquired via id must
be connected to the memcg tree.

Link: https://lkml.kernel.org/r/20230823225430.166925-1-nphamcs@gmail.com
Fixes: f78dfc7b77d5 ("workingset: fix confusion around eviction vs refault container")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Co-developed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: fix get_mctgt_type() kernel-doc

Convert the return values to an ReST list and tidy up the wording while
I'm touching it.

[akpm@linux-foundation.org: changes suggested by Randy]
[willy@infradead

mm: fix get_mctgt_type() kernel-doc

Convert the return values to an ReST list and tidy up the wording while
I'm touching it.

[akpm@linux-foundation.org: changes suggested by Randy]
[willy@infradead.org: another change suggested by Randy]
Link: https://lkml.kernel.org/r/ZOUZtZizeQG7PcsM@casper.infradead.org
Link: https://lkml.kernel.org/r/20230818200630.2719595-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

memcg: remove duplication detection for mem_cgroup_uncharge_swap

__mem_cgroup_uncharge_swap is only called in mem_cgroup_uncharge_swap, if
mem cgroup is disabled, __mem_cgroup_uncharge_swap cannot b

memcg: remove duplication detection for mem_cgroup_uncharge_swap

__mem_cgroup_uncharge_swap is only called in mem_cgroup_uncharge_swap, if
mem cgroup is disabled, __mem_cgroup_uncharge_swap cannot be called.
Therefore, there is no need to judge whether mem_cgroup is disabled or
not.

Link: https://lkml.kernel.org/r/20230819081302.1217098-1-lujialin4@huawei.com
Signed-off-by: Lu Jialin <lujialin4@huawei.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

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>

show more ...

mm: remove folio_test_transhuge()

This function is misleading; people think it means "Is this a THP", when
all it actually does is check whether this is a large folio. Remove it;
the one remaining

mm: remove folio_test_transhuge()

This function is misleading; people think it means "Is this a THP", when
all it actually does is check whether this is a large folio. Remove it;
the one remaining user should have been checking to see whether the folio
is PMD sized or not.

Link: https://lkml.kernel.org/r/20230816151201.3655946-12-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: remove redundant K() macro definition

Patch series "cleanup with helper macro K()".

Use helper macro K() to improve code readability. No functional
modification involved. Remove redundant K()

mm: remove redundant K() macro definition

Patch series "cleanup with helper macro K()".

Use helper macro K() to improve code readability. No functional
modification involved. Remove redundant K() macro definition.


This patch (of 7):

Since commit eb8589b4f8c1 ("mm: move mem_init_print_info() to mm_init.c"),
the K() macro definition has been moved to mm/internal.h. Therefore, the
definitions in mm/memcontrol.c, mm/backing-dev.c and mm/oom_kill.c are
redundant. Drop redundant definitions.

[akpm@linux-foundation.org: oom_kill.c: remove "#undef K", per Kefeng]
Link: https://lkml.kernel.org/r/20230804012559.2617515-1-zhangpeng362@huawei.com
Link: https://lkml.kernel.org/r/20230804012559.2617515-2-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcg: fix wrong function name above obj_cgroup_charge_zswap()

The correct function name is obj_cgroup_may_zswap(). Correct the comment.

Link: https://lkml.kernel.org/r/20230803120021.762279-1-l

mm/memcg: fix wrong function name above obj_cgroup_charge_zswap()

The correct function name is obj_cgroup_may_zswap(). Correct the comment.

Link: https://lkml.kernel.org/r/20230803120021.762279-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm:vmscan: fix inaccurate reclaim during proactive reclaim

Before commit f53af4285d77 ("mm: vmscan: fix extreme overreclaim and swap
floods"), proactive reclaim will extreme overreclaim sometimes.

mm:vmscan: fix inaccurate reclaim during proactive reclaim

Before commit f53af4285d77 ("mm: vmscan: fix extreme overreclaim and swap
floods"), proactive reclaim will extreme overreclaim sometimes. But
proactive reclaim still inaccurate and some extent overreclaim.

Problematic case is easy to construct. Allocate lots of anonymous memory
(e.g., 20G) in a memcg, then swapping by writing memory.recalim and there
is a certain probability of overreclaim. For example, request 1G by
writing memory.reclaim will eventually reclaim 1.7G or other values more
than 1G.

The reason is that reclaimer may have already reclaimed part of requested
memory in one loop, but before adjust sc->nr_to_reclaim in outer loop,
call shrink_lruvec() again will still follow the current sc->nr_to_reclaim
to work. It will eventually lead to overreclaim. In theory, the amount
of reclaimed would be in [request, 2 * request).

Reclaimer usually tends to reclaim more than request. But either direct
or kswapd reclaim have much smaller nr_to_reclaim targets, so it is less
noticeable and not have much impact.

Proactive reclaim can usually come in with a larger value, so the error is
difficult to ignore. Considering proactive reclaim is usually low
frequency, handle the batching into smaller chunks is a better approach.

Link: https://lkml.kernel.org/r/20230721014116.3388-1-yangyifei03@kuaishou.com
Signed-off-by: Efly Young <yangyifei03@kuaishou.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

memcg: convert get_obj_cgroup_from_page to get_obj_cgroup_from_folio

As the one caller now has a folio, pass it in and use it. Removes three
calls to compound_head().

Link: https://lkml.kernel.org

memcg: convert get_obj_cgroup_from_page to get_obj_cgroup_from_folio

As the one caller now has a folio, pass it in and use it. Removes three
calls to compound_head().

Link: https://lkml.kernel.org/r/20230715042343.434588-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: enable page walking API to lock vmas during the walk

walk_page_range() and friends often operate under write-locked mmap_lock.
With introduction of vma locks, the vmas have to be locked as well

mm: enable page walking API to lock vmas during the walk

walk_page_range() and friends often operate under write-locked mmap_lock.
With introduction of vma locks, the vmas have to be locked as well during
such walks to prevent concurrent page faults in these areas. Add an
additional member to mm_walk_ops to indicate locking requirements for the
walk.

The change ensures that page walks which prevent concurrent page faults
by write-locking mmap_lock, operate correctly after introduction of
per-vma locks. With per-vma locks page faults can be handled under vma
lock without taking mmap_lock at all, so write locking mmap_lock would
not stop them. The change ensures vmas are properly locked during such
walks.

A sample issue this solves is do_mbind() performing queue_pages_range()
to queue pages for migration. Without this change a concurrent page
can be faulted into the area and be left out of migration.

Link: https://lkml.kernel.org/r/20230804152724.3090321-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Suggested-by: Jann Horn <jannh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michel Lespinasse <michel@lespinasse.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcg: minor cleanup for mc_handle_present_pte()

When pagetable lock is held, the page will always be page_mapped(). So
remove unneeded page_mapped() check. Also the page can't be freed from
un

mm/memcg: minor cleanup for mc_handle_present_pte()

When pagetable lock is held, the page will always be page_mapped(). So
remove unneeded page_mapped() check. Also the page can't be freed from
under us in this case. So use get_page() to get extra page reference to
simplify the code. No functional change intended.

Link: https://lkml.kernel.org/r/20230717113644.3026478-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcg: fix obsolete comment above MEM_CGROUP_MAX_RECLAIM_LOOPS

Since commit 5660048ccac8 ("mm: move memcg hierarchy reclaim to generic
reclaim code"), mem_cgroup_hierarchical_reclaim() is already

mm/memcg: fix obsolete comment above MEM_CGROUP_MAX_RECLAIM_LOOPS

Since commit 5660048ccac8 ("mm: move memcg hierarchy reclaim to generic
reclaim code"), mem_cgroup_hierarchical_reclaim() is already renamed to
mem_cgroup_soft_reclaim(). Update the corresponding comment.

Link: https://lkml.kernel.org/r/20230713121432.273381-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcg: minor cleanup for MEM_CGROUP_ID_MAX

MEM_CGROUP_ID_MAX is only used when CONFIG_MEMCG is configured. So remove
unneeded !CONFIG_MEMCG variant. Also it's only used in
mem_cgroup_alloc(), s

mm/memcg: minor cleanup for MEM_CGROUP_ID_MAX

MEM_CGROUP_ID_MAX is only used when CONFIG_MEMCG is configured. So remove
unneeded !CONFIG_MEMCG variant. Also it's only used in
mem_cgroup_alloc(), so move it from memcontrol.h to memcontrol.c. And
further define it as:

#define MEM_CGROUP_ID_MAX ((1UL << MEM_CGROUP_ID_SHIFT) - 1)

so if someone changes MEM_CGROUP_ID_SHIFT in the future, then
MEM_CGROUP_ID_MAX will be updated accordingly, as suggested by Muchun.

Link: https://lkml.kernel.org/r/20230708023304.1184111-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

memcg: drop kmem.limit_in_bytes

kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been
deprecated since 58056f77502f ("memcg, kmem: further deprecate
kmem.limit_in_bytes") merged in 5.16

memcg: drop kmem.limit_in_bytes

kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been
deprecated since 58056f77502f ("memcg, kmem: further deprecate
kmem.limit_in_bytes") merged in 5.16. We haven't heard about any serious
users since then but it seems that the mere presence of the file is
causing more harm thatn good. We (SUSE) have had several bug reports from
customers where Docker based containers started to fail because a write to
kmem.limit_in_bytes has failed.

This was unexpected because runc code only expects ENOENT (kmem disabled)
or EBUSY (tasks already running within cgroup). So a new error code was
unexpected and the whole container startup failed. This has been later
addressed by
https://github.com/opencontainers/runc/commit/52390d68040637dfc77f9fda6bbe70952423d380
so current Docker runtimes do not suffer from the problem anymore. There
are still older version of Docker in use and likely hard to get rid of
completely.

Address this by wiping out the file completely and effectively get back to
pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration.

I would recommend backporting to stable trees which have picked up
58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes").

[mhocko@suse.com: restore _KMEM switch case]
Link: https://lkml.kernel.org/r/ZKe5wxdbvPi5Cwd7@dhcp22.suse.cz
Link: https://lkml.kernel.org/r/20230704115240.14672-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcontrol: do not tweak node in mem_cgroup_init()

mem_cgroup_init() request for allocations from each possible node, and
it's used to be a problem because NODE_DATA is not allocated for offline

mm/memcontrol: do not tweak node in mem_cgroup_init()

mem_cgroup_init() request for allocations from each possible node, and
it's used to be a problem because NODE_DATA is not allocated for offline
node. Things have already changed since commit 09f49dca570a9 ("mm: handle
uninitialized numa nodes gracefully"), so it's unnecessary to check for
!node_online nodes here.

How to test?

qemu-system-x86_64 \
-kernel vmlinux \
-initrd full.rootfs.cpio.gz \
-append "console=ttyS0,115200 root=/dev/ram0 nokaslr earlyprintk=serial oops=panic panic_on_warn" \
-drive format=qcow2,file=vm_disk.qcow2,media=disk,if=ide \
-enable-kvm \
-cpu host \
-m 8G,slots=2,maxmem=16G \
-smp cores=4,threads=1,sockets=2 \
-object memory-backend-ram,id=mem0,size=4G \
-object memory-backend-ram,id=mem1,size=4G \
-numa node,memdev=mem0,cpus=0-3,nodeid=0 \
-numa node,memdev=mem1,cpus=4-7,nodeid=1 \
-numa node,nodeid=2 \
-net nic,model=virtio,macaddr=52:54:00:12:34:58 \
-net user \
-nographic \
-rtc base=localtime \
-gdb tcp::6000

Guest state when booting:

[ 0.048881] NUMA: Node 0 [mem 0x00000000-0x0009ffff] + [mem 0x00100000-0xbfffffff] -> [mem 0x00000000-0xbfffffff]
[ 0.050489] NUMA: Node 0 [mem 0x00000000-0xbfffffff] + [mem 0x100000000-0x13fffffff] -> [mem 0x00000000-0x13fffffff]
[ 0.052173] NODE_DATA(0) allocated [mem 0x13fffc000-0x13fffffff]
[ 0.053164] NODE_DATA(1) allocated [mem 0x23fffa000-0x23fffdfff]
[ 0.054187] Zone ranges:
[ 0.054587] DMA [mem 0x0000000000001000-0x0000000000ffffff]
[ 0.055551] DMA32 [mem 0x0000000001000000-0x00000000ffffffff]
[ 0.056515] Normal [mem 0x0000000100000000-0x000000023fffffff]
[ 0.057484] Movable zone start for each node
[ 0.058149] Early memory node ranges
[ 0.058705] node 0: [mem 0x0000000000001000-0x000000000009efff]
[ 0.059679] node 0: [mem 0x0000000000100000-0x00000000bffdffff]
[ 0.060659] node 0: [mem 0x0000000100000000-0x000000013fffffff]
[ 0.061649] node 1: [mem 0x0000000140000000-0x000000023fffffff]
[ 0.062638] Initmem setup node 0 [mem 0x0000000000001000-0x000000013fffffff]
[ 0.063745] Initmem setup node 1 [mem 0x0000000140000000-0x000000023fffffff]
[ 0.064855] DMA zone: 158 reserved pages exceeds freesize 0
[ 0.065746] Initializing node 2 as memoryless
[ 0.066437] Initmem setup node 2 as memoryless
[ 0.067132] DMA zone: 158 reserved pages exceeds freesize 0
[ 0.068037] On node 0, zone DMA: 1 pages in unavailable ranges
[ 0.068265] On node 0, zone DMA: 97 pages in unavailable ranges
[ 0.124755] On node 0, zone Normal: 32 pages in unavailable ranges

cat /sys/devices/system/node/online
0-1
cat /sys/devices/system/node/possible
0-2

Link: https://lkml.kernel.org/r/20230619130442.2487-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/memcg: remove return value of mem_cgroup_scan_tasks()

No user checks the return value of mem_cgroup_scan_tasks(). Make the
return value void.

Link: https://lkml.kernel.org/r/20230616063030.97758

mm/memcg: remove return value of mem_cgroup_scan_tasks()

No user checks the return value of mem_cgroup_scan_tasks(). Make the
return value void.

Link: https://lkml.kernel.org/r/20230616063030.977586-1-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: kill lock|unlock_page_memcg()

Since commit c7c3dec1c9db ("mm: rmap: remove lock_page_memcg()"),
no more user, kill lock_page_memcg() and unlock_page_memcg().

Link: https://lkml.kernel.org/r/202

mm: kill lock|unlock_page_memcg()

Since commit c7c3dec1c9db ("mm: rmap: remove lock_page_memcg()"),
no more user, kill lock_page_memcg() and unlock_page_memcg().

Link: https://lkml.kernel.org/r/20230614143612.62575-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm: ptep_get() conversion

Convert all instances of direct pte_t* dereferencing to instead use
ptep_get() helper. This means that by default, the accesses change from a
C dereference to a READ_ONCE(

mm: ptep_get() conversion

Convert all instances of direct pte_t* dereferencing to instead use
ptep_get() helper. This means that by default, the accesses change from a
C dereference to a READ_ONCE(). This is technically the correct thing to
do since where pgtables are modified by HW (for access/dirty) they are
volatile and therefore we should always ensure READ_ONCE() semantics.

But more importantly, by always using the helper, it can be overridden by
the architecture to fully encapsulate the contents of the pte. Arch code
is deliberately not converted, as the arch code knows best. It is
intended that arch code (arm64) will override the default with its own
implementation that can (e.g.) hide certain bits from the core code, or
determine young/dirty status by mixing in state from another source.

Conversion was done using Coccinelle:

----

// $ make coccicheck \
// COCCI=ptepget.cocci \
// SPFLAGS="--include-headers" \
// MODE=patch

virtual patch

@ depends on patch @
pte_t *v;
@@

- *v
+ ptep_get(v)

----

Then reviewed and hand-edited to avoid multiple unnecessary calls to
ptep_get(), instead opting to store the result of a single call in a
variable, where it is correct to do so. This aims to negate any cost of
READ_ONCE() and will benefit arch-overrides that may be more complex.

Included is a fix for an issue in an earlier version of this patch that
was pointed out by kernel test robot. The issue arose because config
MMU=n elides definition of the ptep helper functions, including
ptep_get(). HUGETLB_PAGE=n configs still define a simple
huge_ptep_clear_flush() for linking purposes, which dereferences the ptep.
So when both configs are disabled, this caused a build error because
ptep_get() is not defined. Fix by continuing to do a direct dereference
when MMU=n. This is safe because for this config the arch code cannot be
trying to virtualize the ptes because none of the ptep helpers are
defined.

Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

mm/various: give up if pte_offset_map[_lock]() fails

Following the examples of nearby code, various functions can just give up
if pte_offset_map() or pte_offset_map_lock() fails. And there's no nee

mm/various: give up if pte_offset_map[_lock]() fails

Following the examples of nearby code, various functions can just give up
if pte_offset_map() or pte_offset_map_lock() fails. And there's no need
for a preliminary pmd_trans_unstable() or other such check, since such
cases are now safely handled inside.

Link: https://lkml.kernel.org/r/7b9bd85d-1652-cbf2-159d-f503b45e5b@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...

memcg: use helper macro FLUSH_TIME

Use helper macro FLUSH_TIME to indicate the flush time to improve the
readability a bit. No functional change intended.

Link: https://lkml.kernel.org/r/2023060307

memcg: use helper macro FLUSH_TIME

Use helper macro FLUSH_TIME to indicate the flush time to improve the
readability a bit. No functional change intended.

Link: https://lkml.kernel.org/r/20230603072116.1101690-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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mm/memcontrol: export memcg.swap watermark via sysfs for v2 memcg

This patch is similar to commit 8e20d4b33266 ("mm/memcontrol: export
memcg->watermark via sysfs for v2 memcg"), but exports the swap

mm/memcontrol: export memcg.swap watermark via sysfs for v2 memcg

This patch is similar to commit 8e20d4b33266 ("mm/memcontrol: export
memcg->watermark via sysfs for v2 memcg"), but exports the swap counter's
watermark.

We allocate jobs to our compute farm using heuristics determined by memory
and swap usage from previous jobs. Tracking the peak swap usage for new
jobs is important for determining when jobs are exceeding their expected
bounds, or when our baseline metrics are getting outdated.

Our toolset was written to use the "memory.memsw.max_usage_in_bytes" file
in cgroups v1, and altering it to poll cgroups v2's "memory.swap.current"
would give less accurate results as well as add complication to the code.
Having this watermark exposed in sysfs is much preferred.

Link: https://lkml.kernel.org/r/20230524181734.125696-1-lars@pixar.com
Signed-off-by: Lars R. Damerow <lars@pixar.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

show more ...