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aab6103b97
1637 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Roman Gushchin
|
aab6103b97 |
mm: memcg: account memory used for memcg vmstats and lruvec stats
The percpu memory used by memcg's memory statistics is already accounted. For consistency, let's enable accounting for vmstats and lruvec stats as well. Link: https://lkml.kernel.org/r/20240501172617.678560-4-shakeel.butt@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: T.J. Mercier <tjmercier@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Shakeel Butt
|
70a64b7919 |
memcg: dynamically allocate lruvec_stats
To decouple the dependency of lruvec_stats on NR_VM_NODE_STAT_ITEMS, we need to dynamically allocate lruvec_stats in the mem_cgroup_per_node structure. Also move the definition of lruvec_stats_percpu and lruvec_stats and related functions to the memcontrol.c to facilitate later patches. No functional changes in the patch. Link: https://lkml.kernel.org/r/20240501172617.678560-3-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: T.J. Mercier <tjmercier@google.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Shakeel Butt
|
59142d87ab |
memcg: reduce memory size of mem_cgroup_events_index
Patch series "memcg: reduce memory consumption by memcg stats", v4. Most of the memory overhead of a memcg object is due to memcg stats maintained by the kernel. Since stats updates happen in performance critical codepaths, the stats are maintained per-cpu and numa specific stats are maintained per-node * per-cpu. This drastically increase the overhead on large machines i.e. large of CPUs and multiple numa nodes. This patch series tries to reduce the overhead by at least not allocating the memory for stats which are not memcg specific. This patch (of 8): mem_cgroup_events_index is a translation table to get the right index of the memcg relevant entry for the general vm_event_item. At the moment, it is defined as integer array. However on a typical system the max entry of vm_event_item (NR_VM_EVENT_ITEMS) is 113, so we don't need to use int as storage type of the array. For now just use int8_t as type and add a BUILD_BUG_ON(). Another benefit of this change is that the translation table fits in 2 cachelines while previously it would require 8 cachelines (assuming 64 bytes cacheline). Link: https://lkml.kernel.org/r/20240501172617.678560-1-shakeel.butt@linux.dev Link: https://lkml.kernel.org/r/20240501172617.678560-2-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: T.J. Mercier <tjmercier@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Breno Leitao
|
78ec6f9df6 |
memcg: fix data-race KCSAN bug in rstats
A data-race issue in memcg rstat occurs when two distinct code paths
access the same 4-byte region concurrently. KCSAN detection triggers the
following BUG as a result.
BUG: KCSAN: data-race in __count_memcg_events / mem_cgroup_css_rstat_flush
write to 0xffffe8ffff98e300 of 4 bytes by task 5274 on cpu 17:
mem_cgroup_css_rstat_flush (mm/memcontrol.c:5850)
cgroup_rstat_flush_locked (kernel/cgroup/rstat.c:243 (discriminator 7))
cgroup_rstat_flush (./include/linux/spinlock.h:401 kernel/cgroup/rstat.c:278)
mem_cgroup_flush_stats.part.0 (mm/memcontrol.c:767)
memory_numa_stat_show (mm/memcontrol.c:6911)
<snip>
read to 0xffffe8ffff98e300 of 4 bytes by task 410848 on cpu 27:
__count_memcg_events (mm/memcontrol.c:725 mm/memcontrol.c:962)
count_memcg_event_mm.part.0 (./include/linux/memcontrol.h:1097 ./include/linux/memcontrol.h:1120)
handle_mm_fault (mm/memory.c:5483 mm/memory.c:5622)
<snip>
value changed: 0x00000029 -> 0x00000000
The race occurs because two code paths access the same "stats_updates"
location. Although "stats_updates" is a per-CPU variable, it is remotely
accessed by another CPU at
cgroup_rstat_flush_locked()->mem_cgroup_css_rstat_flush(), leading to the
data race mentioned.
Considering that memcg_rstat_updated() is in the hot code path, adding a
lock to protect it may not be desirable, especially since this variable
pertains solely to statistics.
Therefore, annotating accesses to stats_updates with READ/WRITE_ONCE() can
prevent KCSAN splats and potential partial reads/writes.
Link: https://lkml.kernel.org/r/20240424125940.2410718-1-leitao@debian.org
Fixes:
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Shakeel Butt
|
91882c1617 |
memcg: simple cleanup of stats update functions
mod_memcg_lruvec_state() is never called from outside of memcontrol.c and with always irq disabled. So, replace it with the irq disabled version and add an assert that irq is disabled in the caller. Similarly mod_objcg_state() is not called from outside of memcontrol.c, so simply make it static and change it's name to __mod_objcg_state(). Link: https://lkml.kernel.org/r/20240420232505.2768428-1-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: T.J. Mercier <tjmercier@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Vlastimil Babka
|
e6100a4590 |
mm, slab: move slab_memcg hooks to mm/memcontrol.c
The hooks make multiple calls to functions in mm/memcontrol.c, including to th current_obj_cgroup() marked __always_inline. It might be faster to make a single call to the hook in mm/memcontrol.c instead. The hooks also don't use almost anything from mm/slub.c. obj_full_size() can move with the hooks and cache_vmstat_idx() to the internal mm/slab.h Link: https://lkml.kernel.org/r/20240326-slab-memcg-v3-2-d85d2563287a@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Jeff Layton <jlayton@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Kees Cook <kees@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Pekka Enberg <penberg@kernel.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Vlastimil Babka
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9f9796b413 |
mm, slab: move memcg charging to post-alloc hook
Patch series "memcg_kmem hooks refactoring", v3. This patch (of 2): The MEMCG_KMEM integration with slab currently relies on two hooks during allocation. memcg_slab_pre_alloc_hook() determines the objcg and charges it, and memcg_slab_post_alloc_hook() assigns the objcg pointer to the allocated object(s). As Linus pointed out, this is unnecessarily complex. Failing to charge due to memcg limits should be rare, so we can optimistically allocate the object(s) and do the charging together with assigning the objcg pointer in a single post_alloc hook. In the rare case the charging fails, we can free the object(s) back. This simplifies the code (no need to pass around the objcg pointer) and potentially allows to separate charging from allocation in cases where it's common that the allocation would be immediately freed, and the memcg handling overhead could be saved. [vbabka@suse.cz: fix call to memcg_alloc_abort_single()] Link: https://lkml.kernel.org/r/4af50be2-4109-45e5-8a36-2136252a635e@suse.cz [roman.gushchin@linux.dev: comment fixup] Link: https://lkml.kernel.org/r/Zg2LsNm6twOmG69l@P9FQF9L96D.corp.robot.car Link: https://lkml.kernel.org/r/20240326-slab-memcg-v3-0-d85d2563287a@suse.cz Link: https://lkml.kernel.org/r/20240326-slab-memcg-v3-1-d85d2563287a@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/all/CAHk-=whYOOdM7jWy5jdrAm8LxcgCMFyk2bt8fYYvZzM4U-zAQA@mail.gmail.com/ Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Jeff Layton <jlayton@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Kees Cook <kees@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Pekka Enberg <penberg@kernel.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Aishwarya TCV <aishwarya.tcv@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
b7b098cf00 |
mm: always initialise folio->_deferred_list
Patch series "Various significant MM patches". These patches all interact in annoying ways which make it tricky to send them out in any way other than a big batch, even though there's not really an overarching theme to connect them. The big effects of this patch series are: - folio_test_hugetlb() becomes reliable, even when called without a page reference - We free up PG_slab, and we could always use more page flags - We no longer need to check PageSlab before calling page_mapcount() This patch (of 9): For compound pages which are at least order-2 (and hence have a deferred_list), initialise it and then we can check at free that the page is not part of a deferred list. We recently found this useful to rule out a source of corruption. [peterx@redhat.com: always initialise folio->_deferred_list] Link: https://lkml.kernel.org/r/20240417211836.2742593-2-peterx@redhat.com Link: https://lkml.kernel.org/r/20240321142448.1645400-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240321142448.1645400-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
21c690a349 |
mm: introduce slabobj_ext to support slab object extensions
Currently slab pages can store only vectors of obj_cgroup pointers in page->memcg_data. Introduce slabobj_ext structure to allow more data to be stored for each slab object. Wrap obj_cgroup into slabobj_ext to support current functionality while allowing to extend slabobj_ext in the future. Link: https://lkml.kernel.org/r/20240321163705.3067592-7-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andreas Hindborg <a.hindborg@samsung.com> Cc: Benno Lossin <benno.lossin@proton.me> Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Gary Guo <gary@garyguo.net> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yosry Ahmed
|
91b71e78b8 |
mm: memcg: add NULL check to obj_cgroup_put()
9 out of 16 callers perform a NULL check before calling obj_cgroup_put(). Move the NULL check in the function, similar to mem_cgroup_put(). The unlikely() NULL check in current_objcg_update() was left alone to avoid dropping the unlikey() annotation as this a fast path. Link: https://lkml.kernel.org/r/20240316015803.2777252-1-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> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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be5a9e17a2 |
memcg: remove mem_cgroup_uncharge_list()
All users have been converted to mem_cgroup_uncharge_folios() so we can remove this API. Link: https://lkml.kernel.org/r/20240227174254.710559-14-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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4882c80975 |
memcg: add mem_cgroup_uncharge_folios()
Almost identical to mem_cgroup_uncharge_list(), except it takes a folio_batch instead of a list_head. Link: https://lkml.kernel.org/r/20240227174254.710559-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Zi Yan
|
b8791381d7 |
mm: memcg: make memcg huge page split support any order split
It sets memcg information for the pages after the split. A new parameter new_order is added to tell the order of subpages in the new page, always 0 for now. It prepares for upcoming changes to support split huge page to any lower order. Link: https://lkml.kernel.org/r/20240226205534.1603748-6-zi.yan@sent.com Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Zi Yan
|
502003bb76 |
mm/memcg: use order instead of nr in split_page_memcg()
We do not have non power of two pages, using nr is error prone if nr is not power-of-two. Use page order instead. Link: https://lkml.kernel.org/r/20240226205534.1603748-4-zi.yan@sent.com Signed-off-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zach O'Keefe <zokeefe@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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T.J. Mercier
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287d5fedb3 |
mm: memcg: use larger batches for proactive reclaim
Before 388536ac291 ("mm:vmscan: fix inaccurate reclaim during proactive
reclaim") we passed the number of pages for the reclaim request directly
to try_to_free_mem_cgroup_pages, which could lead to significant
overreclaim. After
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T.J. Mercier
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13ef742457 |
mm: memcg: don't periodically flush stats when memcg is disabled
The root memcg is onlined even when memcg is disabled. When it's onlined a 2 second periodic stat flush is started, but no stat flushing is required when memcg is disabled because there can be no child memcgs. Most calls to flush memcg stats are avoided when memcg is disabled as a result of the mem_cgroup_disabled check added in |
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Shakeel Butt
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d9b3ce8769 |
mm: writeback: ratelimit stat flush from mem_cgroup_wb_stats
One of our workloads (Postgres 14) has regressed when migrated from 5.10
to 6.1 upstream kernel. The regression can be reproduced by sysbench's
oltp_write_only benchmark. It seems like the always on rstat flush in
mem_cgroup_wb_stats() is causing the regression. So, rate limit that
specific rstat flush. One potential consequence would be the dirty
throttling might be decided on stale memcg stats. However from our
benchmarks and production traffic we have not observed any change in the
dirty throttling behavior of the application.
Link: https://lkml.kernel.org/r/20240118184235.618164-1-shakeelb@google.com
Fixes:
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Matthew Wilcox (Oracle)
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f6c7590b4e |
memcg: use a folio in get_mctgt_type_thp
Replace five calls to compound_head() with one. Link: https://lkml.kernel.org/r/20240111181219.3462852-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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b67fa6e47b |
memcg: use a folio in get_mctgt_type
Replace seven calls to compound_head() with one. We still use the page as page_mapped() is different from folio_mapped(). Link: https://lkml.kernel.org/r/20240111181219.3462852-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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b46777da7d |
memcg: return the folio in union mc_target
All users of target.page convert it to the folio, so we can just return the folio directly and save a few calls to compound_head(). Link: https://lkml.kernel.org/r/20240111181219.3462852-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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b267e1a3e4 |
memcg: convert mem_cgroup_move_charge_pte_range() to use a folio
Patch series "Convert memcontrol charge moving to use folios". No part of these patches should change behaviour; all the called functions already convert from page to folio, so this ought to simply be a reduction in the number of calls to compound_head(). This patch (of 4): Remove many calls to compound_head() by calling page_folio() once at the start of each stanza which receives a struct page from 'target'. There should be no change in behaviour here as all the called functions start out by converting the page to its folio. Link: https://lkml.kernel.org/r/20240111181219.3462852-1-willy@infradead.org Link: https://lkml.kernel.org/r/20240111181219.3462852-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Muchun Song <muchun.song@linux.dev> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Johannes Weiner
|
118642d7f6 |
mm: memcontrol: clarify swapaccount=0 deprecation warning
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:
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Yosry Ahmed
|
9cee7e8ef3 |
mm: memcg: optimize parent iteration in memcg_rstat_updated()
In memcg_rstat_updated(), we iterate the memcg being updated and its
parents to update memcg->vmstats_percpu->stats_updates in the fast path
(i.e. no atomic updates). According to my math, this is 3 memory loads
(and potentially 3 cache misses) per memcg:
- Load the address of memcg->vmstats_percpu.
- Load vmstats_percpu->stats_updates (based on some percpu calculation).
- Load the address of the parent memcg.
Avoid most of the cache misses by caching a pointer from each struct
memcg_vmstats_percpu to its parent on the corresponding CPU. In this
case, for the first memcg we have 2 memory loads (same as above):
- Load the address of memcg->vmstats_percpu.
- Load vmstats_percpu->stats_updates (based on some percpu calculation).
Then for each additional memcg, we need a single load to get the
parent's stats_updates directly. This reduces the number of loads from
O(3N) to O(2+N) -- where N is the number of memcgs we need to iterate.
Additionally, stash a pointer to memcg->vmstats in each struct
memcg_vmstats_percpu such that we can access the atomic counter that all
CPUs fold into, memcg->vmstats->stats_updates.
memcg_should_flush_stats() is changed to memcg_vmstats_needs_flush() to
accept a struct memcg_vmstats pointer accordingly.
In struct memcg_vmstats_percpu, make sure both pointers together with
stats_updates live on the same cacheline. Finally, update
mem_cgroup_alloc() to take in a parent pointer and initialize the new
cache pointers on each CPU. The percpu loop in mem_cgroup_alloc() may
look concerning, but there are multiple similar loops in the cgroup
creation path (e.g. cgroup_rstat_init()), most of which are hidden
within alloc_percpu().
According to Oliver's testing [1], this fixes multiple 30-38%
regressions in vm-scalability, will-it-scale-tlb_flush2, and
will-it-scale-fallocate1. This comes at a cost of 2 more pointers per
CPU (<2KB on a machine with 128 CPUs).
[1] https://lore.kernel.org/lkml/ZbDJsfsZt2ITyo61@xsang-OptiPlex-9020/
[yosryahmed@google.com: fix struct memcg_vmstats_percpu size and alignment]
Link: https://lkml.kernel.org/r/20240203044612.1234216-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20240124100023.660032-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Fixes:
|
||
|
Johannes Weiner
|
63fd327016 |
mm: memcontrol: don't throttle dying tasks on memory.high
While investigating hosts with high cgroup memory pressures, Tejun found culprit zombie tasks that had were holding on to a lot of memory, had SIGKILL pending, but were stuck in memory.high reclaim. In the past, we used to always force-charge allocations from tasks that were exiting in order to accelerate them dying and freeing up their rss. This changed for memory.max in |
||
Linus Torvalds
|
fb46e22a9e |
Many singleton patches against the MM code. The patch series which
are included in this merge do the following:
- Peng Zhang has done some mapletree maintainance work in the
series
"maple_tree: add mt_free_one() and mt_attr() helpers"
"Some cleanups of maple tree"
- In the series "mm: use memmap_on_memory semantics for dax/kmem"
Vishal Verma has altered the interworking between memory-hotplug
and dax/kmem so that newly added 'device memory' can more easily
have its memmap placed within that newly added memory.
- Matthew Wilcox continues folio-related work (including a few
fixes) in the patch series
"Add folio_zero_tail() and folio_fill_tail()"
"Make folio_start_writeback return void"
"Fix fault handler's handling of poisoned tail pages"
"Convert aops->error_remove_page to ->error_remove_folio"
"Finish two folio conversions"
"More swap folio conversions"
- Kefeng Wang has also contributed folio-related work in the series
"mm: cleanup and use more folio in page fault"
- Jim Cromie has improved the kmemleak reporting output in the
series "tweak kmemleak report format".
- In the series "stackdepot: allow evicting stack traces" Andrey
Konovalov to permits clients (in this case KASAN) to cause
eviction of no longer needed stack traces.
- Charan Teja Kalla has fixed some accounting issues in the page
allocator's atomic reserve calculations in the series "mm:
page_alloc: fixes for high atomic reserve caluculations".
- Dmitry Rokosov has added to the samples/ dorectory some sample
code for a userspace memcg event listener application. See the
series "samples: introduce cgroup events listeners".
- Some mapletree maintanance work from Liam Howlett in the series
"maple_tree: iterator state changes".
- Nhat Pham has improved zswap's approach to writeback in the
series "workload-specific and memory pressure-driven zswap
writeback".
- DAMON/DAMOS feature and maintenance work from SeongJae Park in
the series
"mm/damon: let users feed and tame/auto-tune DAMOS"
"selftests/damon: add Python-written DAMON functionality tests"
"mm/damon: misc updates for 6.8"
- Yosry Ahmed has improved memcg's stats flushing in the series
"mm: memcg: subtree stats flushing and thresholds".
- In the series "Multi-size THP for anonymous memory" Ryan Roberts
has added a runtime opt-in feature to transparent hugepages which
improves performance by allocating larger chunks of memory during
anonymous page faults.
- Matthew Wilcox has also contributed some cleanup and maintenance
work against eh buffer_head code int he series "More buffer_head
cleanups".
- Suren Baghdasaryan has done work on Andrea Arcangeli's series
"userfaultfd move option". UFFDIO_MOVE permits userspace heap
compaction algorithms to move userspace's pages around rather than
UFFDIO_COPY'a alloc/copy/free.
- Stefan Roesch has developed a "KSM Advisor", in the series
"mm/ksm: Add ksm advisor". This is a governor which tunes KSM's
scanning aggressiveness in response to userspace's current needs.
- Chengming Zhou has optimized zswap's temporary working memory
use in the series "mm/zswap: dstmem reuse optimizations and
cleanups".
- Matthew Wilcox has performed some maintenance work on the
writeback code, both code and within filesystems. The series is
"Clean up the writeback paths".
- Andrey Konovalov has optimized KASAN's handling of alloc and
free stack traces for secondary-level allocators, in the series
"kasan: save mempool stack traces".
- Andrey also performed some KASAN maintenance work in the series
"kasan: assorted clean-ups".
- David Hildenbrand has gone to town on the rmap code. Cleanups,
more pte batching, folio conversions and more. See the series
"mm/rmap: interface overhaul".
- Kinsey Ho has contributed some maintenance work on the MGLRU
code in the series "mm/mglru: Kconfig cleanup".
- Matthew Wilcox has contributed lruvec page accounting code
cleanups in the series "Remove some lruvec page accounting
functions".
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Merge tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Many singleton patches against the MM code. The patch series which are
included in this merge do the following:
- Peng Zhang has done some mapletree maintainance work in the series
'maple_tree: add mt_free_one() and mt_attr() helpers'
'Some cleanups of maple tree'
- In the series 'mm: use memmap_on_memory semantics for dax/kmem'
Vishal Verma has altered the interworking between memory-hotplug
and dax/kmem so that newly added 'device memory' can more easily
have its memmap placed within that newly added memory.
- Matthew Wilcox continues folio-related work (including a few fixes)
in the patch series
'Add folio_zero_tail() and folio_fill_tail()'
'Make folio_start_writeback return void'
'Fix fault handler's handling of poisoned tail pages'
'Convert aops->error_remove_page to ->error_remove_folio'
'Finish two folio conversions'
'More swap folio conversions'
- Kefeng Wang has also contributed folio-related work in the series
'mm: cleanup and use more folio in page fault'
- Jim Cromie has improved the kmemleak reporting output in the series
'tweak kmemleak report format'.
- In the series 'stackdepot: allow evicting stack traces' Andrey
Konovalov to permits clients (in this case KASAN) to cause eviction
of no longer needed stack traces.
- Charan Teja Kalla has fixed some accounting issues in the page
allocator's atomic reserve calculations in the series 'mm:
page_alloc: fixes for high atomic reserve caluculations'.
- Dmitry Rokosov has added to the samples/ dorectory some sample code
for a userspace memcg event listener application. See the series
'samples: introduce cgroup events listeners'.
- Some mapletree maintanance work from Liam Howlett in the series
'maple_tree: iterator state changes'.
- Nhat Pham has improved zswap's approach to writeback in the series
'workload-specific and memory pressure-driven zswap writeback'.
- DAMON/DAMOS feature and maintenance work from SeongJae Park in the
series
'mm/damon: let users feed and tame/auto-tune DAMOS'
'selftests/damon: add Python-written DAMON functionality tests'
'mm/damon: misc updates for 6.8'
- Yosry Ahmed has improved memcg's stats flushing in the series 'mm:
memcg: subtree stats flushing and thresholds'.
- In the series 'Multi-size THP for anonymous memory' Ryan Roberts
has added a runtime opt-in feature to transparent hugepages which
improves performance by allocating larger chunks of memory during
anonymous page faults.
- Matthew Wilcox has also contributed some cleanup and maintenance
work against eh buffer_head code int he series 'More buffer_head
cleanups'.
- Suren Baghdasaryan has done work on Andrea Arcangeli's series
'userfaultfd move option'. UFFDIO_MOVE permits userspace heap
compaction algorithms to move userspace's pages around rather than
UFFDIO_COPY'a alloc/copy/free.
- Stefan Roesch has developed a 'KSM Advisor', in the series 'mm/ksm:
Add ksm advisor'. This is a governor which tunes KSM's scanning
aggressiveness in response to userspace's current needs.
- Chengming Zhou has optimized zswap's temporary working memory use
in the series 'mm/zswap: dstmem reuse optimizations and cleanups'.
- Matthew Wilcox has performed some maintenance work on the writeback
code, both code and within filesystems. The series is 'Clean up the
writeback paths'.
- Andrey Konovalov has optimized KASAN's handling of alloc and free
stack traces for secondary-level allocators, in the series 'kasan:
save mempool stack traces'.
- Andrey also performed some KASAN maintenance work in the series
'kasan: assorted clean-ups'.
- David Hildenbrand has gone to town on the rmap code. Cleanups, more
pte batching, folio conversions and more. See the series 'mm/rmap:
interface overhaul'.
- Kinsey Ho has contributed some maintenance work on the MGLRU code
in the series 'mm/mglru: Kconfig cleanup'.
- Matthew Wilcox has contributed lruvec page accounting code cleanups
in the series 'Remove some lruvec page accounting functions'"
* tag 'mm-stable-2024-01-08-15-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (361 commits)
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER
mm, treewide: introduce NR_PAGE_ORDERS
selftests/mm: add separate UFFDIO_MOVE test for PMD splitting
selftests/mm: skip test if application doesn't has root privileges
selftests/mm: conform test to TAP format output
selftests: mm: hugepage-mmap: conform to TAP format output
selftests/mm: gup_test: conform test to TAP format output
mm/selftests: hugepage-mremap: conform test to TAP format output
mm/vmstat: move pgdemote_* out of CONFIG_NUMA_BALANCING
mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large
mm/memcontrol: remove __mod_lruvec_page_state()
mm/khugepaged: use a folio more in collapse_file()
slub: use a folio in __kmalloc_large_node
slub: use folio APIs in free_large_kmalloc()
slub: use alloc_pages_node() in alloc_slab_page()
mm: remove inc/dec lruvec page state functions
mm: ratelimit stat flush from workingset shrinker
kasan: stop leaking stack trace handles
mm/mglru: remove CONFIG_TRANSPARENT_HUGEPAGE
mm/mglru: add dummy pmd_dirty()
...
|
||
|
Linus Torvalds
|
d30e51aa7b |
slab updates for 6.8
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Merge tag 'slab-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka:
- SLUB: delayed freezing of CPU partial slabs (Chengming Zhou)
Freezing is an operation involving double_cmpxchg() that makes a slab
exclusive for a particular CPU. Chengming noticed that we use it also
in situations where we are not yet installing the slab as the CPU
slab, because freezing also indicates that the slab is not on the
shared list. This results in redundant freeze/unfreeze operation and
can be avoided by marking separately the shared list presence by
reusing the PG_workingset flag.
This approach neatly avoids the issues described in
|
||
|
Linus Torvalds
|
c604110e66 |
vfs-6.8.misc
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Merge tag 'vfs-6.8.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"This contains the usual miscellaneous features, cleanups, and fixes
for vfs and individual fses.
Features:
- Add Jan Kara as VFS reviewer
- Show correct device and inode numbers in proc/<pid>/maps for vma
files on stacked filesystems. This is now easily doable thanks to
the backing file work from the last cycles. This comes with
selftests
Cleanups:
- Remove a redundant might_sleep() from wait_on_inode()
- Initialize pointer with NULL, not 0
- Clarify comment on access_override_creds()
- Rework and simplify eventfd_signal() and eventfd_signal_mask()
helpers
- Process aio completions in batches to avoid needless wakeups
- Completely decouple struct mnt_idmap from namespaces. We now only
keep the actual idmapping around and don't stash references to
namespaces
- Reformat maintainer entries to indicate that a given subsystem
belongs to fs/
- Simplify fput() for files that were never opened
- Get rid of various pointless file helpers
- Rename various file helpers
- Rename struct file members after SLAB_TYPESAFE_BY_RCU switch from
last cycle
- Make relatime_need_update() return bool
- Use GFP_KERNEL instead of GFP_USER when allocating superblocks
- Replace deprecated ida_simple_*() calls with their current ida_*()
counterparts
Fixes:
- Fix comments on user namespace id mapping helpers. They aren't
kernel doc comments so they shouldn't be using /**
- s/Retuns/Returns/g in various places
- Add missing parameter documentation on can_move_mount_beneath()
- Rename i_mapping->private_data to i_mapping->i_private_data
- Fix a false-positive lockdep warning in pipe_write() for watch
queues
- Improve __fget_files_rcu() code generation to improve performance
- Only notify writer that pipe resizing has finished after setting
pipe->max_usage otherwise writers are never notified that the pipe
has been resized and hang
- Fix some kernel docs in hfsplus
- s/passs/pass/g in various places
- Fix kernel docs in ntfs
- Fix kcalloc() arguments order reported by gcc 14
- Fix uninitialized value in reiserfs"
* tag 'vfs-6.8.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits)
reiserfs: fix uninit-value in comp_keys
watch_queue: fix kcalloc() arguments order
ntfs: dir.c: fix kernel-doc function parameter warnings
fs: fix doc comment typo fs tree wide
selftests/overlayfs: verify device and inode numbers in /proc/pid/maps
fs/proc: show correct device and inode numbers in /proc/pid/maps
eventfd: Remove usage of the deprecated ida_simple_xx() API
fs: super: use GFP_KERNEL instead of GFP_USER for super block allocation
fs/hfsplus: wrapper.c: fix kernel-doc warnings
fs: add Jan Kara as reviewer
fs/inode: Make relatime_need_update return bool
pipe: wakeup wr_wait after setting max_usage
file: remove __receive_fd()
file: stop exposing receive_fd_user()
fs: replace f_rcuhead with f_task_work
file: remove pointless wrapper
file: s/close_fd_get_file()/file_close_fd()/g
Improve __fget_files_rcu() code generation (and thus __fget_light())
file: massage cleanup of files that failed to open
fs/pipe: Fix lockdep false-positive in watchqueue pipe_write()
...
|
||
|
Matthew Wilcox (Oracle)
|
c701123bd6 |
mm/memcontrol: remove __mod_lruvec_page_state()
There are no more callers of __mod_lruvec_page_state(), so convert the implementation to __lruvec_stat_mod_folio(), removing two calls to compound_head() (one explicit, one hidden inside page_memcg()). Link: https://lkml.kernel.org/r/20231228085748.1083901-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Nhat Pham
|
501a06fe8e |
zswap: memcontrol: implement zswap writeback disabling
During our experiment with zswap, we sometimes observe swap IOs due to occasional zswap store failures and writebacks-to-swap. These swapping IOs prevent many users who cannot tolerate swapping from adopting zswap to save memory and improve performance where possible. This patch adds the option to disable this behavior entirely: do not writeback to backing swapping device when a zswap store attempt fail, and do not write pages in the zswap pool back to the backing swap device (both when the pool is full, and when the new zswap shrinker is called). This new behavior can be opted-in/out on a per-cgroup basis via a new cgroup file. By default, writebacks to swap device is enabled, which is the previous behavior. Initially, writeback is enabled for the root cgroup, and a newly created cgroup will inherit the current setting of its parent. Note that this is subtly different from setting memory.swap.max to 0, as it still allows for pages to be stored in the zswap pool (which itself consumes swap space in its current form). This patch should be applied on top of the zswap shrinker series: https://lore.kernel.org/linux-mm/20231130194023.4102148-1-nphamcs@gmail.com/ as it also disables the zswap shrinker, a major source of zswap writebacks. For the most part, this feature is motivated by internal parties who have already established their opinions regarding swapping - the workloads that are highly sensitive to IO, and especially those who are using servers with really slow disk performance (for instance, massive but slow HDDs). For these folks, it's impossible to convince them to even entertain zswap if swapping also comes as a packaged deal. Writeback disabling is quite a useful feature in these situations - on a mixed workloads deployment, they can disable writeback for the more IO-sensitive workloads, and enable writeback for other background workloads. For instance, on a server with HDD, I allocate memories and populate them with random values (so that zswap store will always fail), and specify memory.high low enough to trigger reclaim. The time it takes to allocate the memories and just read through it a couple of times (doing silly things like computing the values' average etc.): zswap.writeback disabled: real 0m30.537s user 0m23.687s sys 0m6.637s 0 pages swapped in 0 pages swapped out zswap.writeback enabled: real 0m45.061s user 0m24.310s sys 0m8.892s 712686 pages swapped in 461093 pages swapped out (the last two lines are from vmstat -s). [nphamcs@gmail.com: add a comment about recurring zswap store failures leading to reclaim inefficiency] Link: https://lkml.kernel.org/r/20231221005725.3446672-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231207192406.3809579-1-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Acked-by: Chris Li <chrisl@kernel.org> Cc: Dan Streetman <ddstreet@ieee.org> Cc: David Heidelberg <david@ixit.cz> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Baolin Wang
|
9bcef5973e |
mm: memcg: fix split queue list crash when large folio migration
When running autonuma with enabling multi-size THP, I encountered the following kernel crash issue: [ 134.290216] list_del corruption. prev->next should be fffff9ad42e1c490, but was dead000000000100. (prev=fffff9ad42399890) [ 134.290877] kernel BUG at lib/list_debug.c:62! [ 134.291052] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 134.291210] CPU: 56 PID: 8037 Comm: numa01 Kdump: loaded Tainted: G E 6.7.0-rc4+ #20 [ 134.291649] RIP: 0010:__list_del_entry_valid_or_report+0x97/0xb0 ...... [ 134.294252] Call Trace: [ 134.294362] <TASK> [ 134.294440] ? die+0x33/0x90 [ 134.294561] ? do_trap+0xe0/0x110 ...... [ 134.295681] ? __list_del_entry_valid_or_report+0x97/0xb0 [ 134.295842] folio_undo_large_rmappable+0x99/0x100 [ 134.296003] destroy_large_folio+0x68/0x70 [ 134.296172] migrate_folio_move+0x12e/0x260 [ 134.296264] ? __pfx_remove_migration_pte+0x10/0x10 [ 134.296389] migrate_pages_batch+0x495/0x6b0 [ 134.296523] migrate_pages+0x1d0/0x500 [ 134.296646] ? __pfx_alloc_misplaced_dst_folio+0x10/0x10 [ 134.296799] migrate_misplaced_folio+0x12d/0x2b0 [ 134.296953] do_numa_page+0x1f4/0x570 [ 134.297121] __handle_mm_fault+0x2b0/0x6c0 [ 134.297254] handle_mm_fault+0x107/0x270 [ 134.300897] do_user_addr_fault+0x167/0x680 [ 134.304561] exc_page_fault+0x65/0x140 [ 134.307919] asm_exc_page_fault+0x22/0x30 The reason for the crash is that, the commit |
||
|
Yosry Ahmed
|
7d7ef0a468 |
mm: memcg: restore subtree stats flushing
Stats flushing for memcg currently follows the following rules: - Always flush the entire memcg hierarchy (i.e. flush the root). - Only one flusher is allowed at a time. If someone else tries to flush concurrently, they skip and return immediately. - A periodic flusher flushes all the stats every 2 seconds. The reason this approach is followed is because all flushes are serialized by a global rstat spinlock. On the memcg side, flushing is invoked from userspace reads as well as in-kernel flushers (e.g. reclaim, refault, etc). This approach aims to avoid serializing all flushers on the global lock, which can cause a significant performance hit under high concurrency. This approach has the following problems: - Occasionally a userspace read of the stats of a non-root cgroup will be too expensive as it has to flush the entire hierarchy [1]. - Sometimes the stats accuracy are compromised if there is an ongoing flush, and we skip and return before the subtree of interest is actually flushed, yielding stale stats (by up to 2s due to periodic flushing). This is more visible when reading stats from userspace, but can also affect in-kernel flushers. The latter problem is particulary a concern when userspace reads stats after an event occurs, but gets stats from before the event. Examples: - When memory usage / pressure spikes, a userspace OOM handler may look at the stats of different memcgs to select a victim based on various heuristics (e.g. how much private memory will be freed by killing this). Reading stale stats from before the usage spike in this case may cause a wrongful OOM kill. - A proactive reclaimer may read the stats after writing to memory.reclaim to measure the success of the reclaim operation. Stale stats from before reclaim may give a false negative. - Reading the stats of a parent and a child memcg may be inconsistent (child larger than parent), if the flush doesn't happen when the parent is read, but happens when the child is read. As for in-kernel flushers, they will occasionally get stale stats. No regressions are currently known from this, but if there are regressions, they would be very difficult to debug and link to the source of the problem. This patch aims to fix these problems by restoring subtree flushing, and removing the unified/coalesced flushing logic that skips flushing if there is an ongoing flush. This change would introduce a significant regression with global stats flushing thresholds. With per-memcg stats flushing thresholds, this seems to perform really well. The thresholds protect the underlying lock from unnecessary contention. This patch was tested in two ways to ensure the latency of flushing is up to par, on a machine with 384 cpus: - A synthetic test with 5000 concurrent workers in 500 cgroups doing allocations and reclaim, as well as 1000 readers for memory.stat (variation of [2]). No regressions were noticed in the total runtime. Note that significant regressions in this test are observed with global stats thresholds, but not with per-memcg thresholds. - A synthetic stress test for concurrently reading memcg stats while memory allocation/freeing workers are running in the background, provided by Wei Xu [3]. With 250k threads reading the stats every 100ms in 50k cgroups, 99.9% of reads take <= 50us. Less than 0.01% of reads take more than 1ms, and no reads take more than 100ms. [1] https://lore.kernel.org/lkml/CABWYdi0c6__rh-K7dcM_pkf9BJdTRtAU08M43KO9ME4-dsgfoQ@mail.gmail.com/ [2] https://lore.kernel.org/lkml/CAJD7tka13M-zVZTyQJYL1iUAYvuQ1fcHbCjcOBZcz6POYTV-4g@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CAAPL-u9D2b=iF5Lf_cRnKxUfkiEe0AMDTu6yhrUAzX0b6a6rDg@mail.gmail.com/ [akpm@linux-foundation.org: fix mm/zswap.c] [yosryahmed@google.com: remove stats flushing mutex] Link: https://lkml.kernel.org/r/CAJD7tkZgP3m-VVPn+fF_YuvXeQYK=tZZjJHj=dzD=CcSSpp2qg@mail.gmail.com Link: https://lkml.kernel.org/r/20231129032154.3710765-6-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Acked-by: Shakeel Butt <shakeelb@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yosry Ahmed
|
8d59d2214c |
mm: memcg: make stats flushing threshold per-memcg
A global counter for the magnitude of memcg stats update is maintained on
the memcg side to avoid invoking rstat flushes when the pending updates
are not significant. This avoids unnecessary flushes, which are not very
cheap even if there isn't a lot of stats to flush. It also avoids
unnecessary lock contention on the underlying global rstat lock.
Make this threshold per-memcg. The scheme is followed where percpu (now
also per-memcg) counters are incremented in the update path, and only
propagated to per-memcg atomics when they exceed a certain threshold.
This provides two benefits: (a) On large machines with a lot of memcgs,
the global threshold can be reached relatively fast, so guarding the
underlying lock becomes less effective. Making the threshold per-memcg
avoids this.
(b) Having a global threshold makes it hard to do subtree flushes, as we
cannot reset the global counter except for a full flush. Per-memcg
counters removes this as a blocker from doing subtree flushes, which helps
avoid unnecessary work when the stats of a small subtree are needed.
Nothing is free, of course. This comes at a cost: (a) A new per-cpu
counter per memcg, consuming NR_CPUS * NR_MEMCGS * 4 bytes. The extra
memory usage is insigificant.
(b) More work on the update side, although in the common case it will only
be percpu counter updates. The amount of work scales with the number of
ancestors (i.e. tree depth). This is not a new concept, adding a cgroup
to the rstat tree involves a parent loop, so is charging. Testing results
below show no significant regressions.
(c) The error margin in the stats for the system as a whole increases from
NR_CPUS * MEMCG_CHARGE_BATCH to NR_CPUS * MEMCG_CHARGE_BATCH * NR_MEMCGS.
This is probably fine because we have a similar per-memcg error in charges
coming from percpu stocks, and we have a periodic flusher that makes sure
we always flush all the stats every 2s anyway.
This patch was tested to make sure no significant regressions are
introduced on the update path as follows. The following benchmarks were
ran in a cgroup that is 2 levels deep (/sys/fs/cgroup/a/b/):
(1) Running 22 instances of netperf on a 44 cpu machine with
hyperthreading disabled. All instances are run in a level 2 cgroup, as
well as netserver:
# netserver -6
# netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
Averaging 20 runs, the numbers are as follows:
Base: 40198.0 mbps
Patched: 38629.7 mbps (-3.9%)
The regression is minimal, especially for 22 instances in the same
cgroup sharing all ancestors (so updating the same atomics).
(2) will-it-scale page_fault tests. These tests (specifically
per_process_ops in page_fault3 test) detected a 25.9% regression before
for a change in the stats update path [1]. These are the
numbers from 10 runs (+ is good) on a machine with 256 cpus:
LABEL | MEAN | MEDIAN | STDDEV |
------------------------------+-------------+-------------+-------------
page_fault1_per_process_ops | | | |
(A) base | 270249.164 | 265437.000 | 13451.836 |
(B) patched | 261368.709 | 255725.000 | 13394.767 |
| -3.29% | -3.66% | |
page_fault1_per_thread_ops | | | |
(A) base | 242111.345 | 239737.000 | 10026.031 |
(B) patched | 237057.109 | 235305.000 | 9769.687 |
| -2.09% | -1.85% | |
page_fault1_scalability | | |
(A) base | 0.034387 | 0.035168 | 0.0018283 |
(B) patched | 0.033988 | 0.034573 | 0.0018056 |
| -1.16% | -1.69% | |
page_fault2_per_process_ops | | |
(A) base | 203561.836 | 203301.000 | 2550.764 |
(B) patched | 197195.945 | 197746.000 | 2264.263 |
| -3.13% | -2.73% | |
page_fault2_per_thread_ops | | |
(A) base | 171046.473 | 170776.000 | 1509.679 |
(B) patched | 166626.327 | 166406.000 | 768.753 |
| -2.58% | -2.56% | |
page_fault2_scalability | | |
(A) base | 0.054026 | 0.053821 | 0.00062121 |
(B) patched | 0.053329 | 0.05306 | 0.00048394 |
| -1.29% | -1.41% | |
page_fault3_per_process_ops | | |
(A) base | 1295807.782 | 1297550.000 | 5907.585 |
(B) patched | 1275579.873 | 1273359.000 | 8759.160 |
| -1.56% | -1.86% | |
page_fault3_per_thread_ops | | |
(A) base | 391234.164 | 390860.000 | 1760.720 |
(B) patched | 377231.273 | 376369.000 | 1874.971 |
| -3.58% | -3.71% | |
page_fault3_scalability | | |
(A) base | 0.60369 | 0.60072 | 0.0083029 |
(B) patched | 0.61733 | 0.61544 | 0.009855 |
| +2.26% | +2.45% | |
All regressions seem to be minimal, and within the normal variance for the
benchmark. The fix for [1] assumes that 3% is noise -- and there were no
further practical complaints), so hopefully this means that such
variations in these microbenchmarks do not reflect on practical workloads.
(3) I also ran stress-ng in a nested cgroup and did not observe any
obvious regressions.
[1]https://lore.kernel.org/all/20190520063534.GB19312@shao2-debian/
Link: https://lkml.kernel.org/r/20231129032154.3710765-4-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Yosry Ahmed
|
e0bf1dc859 |
mm: memcg: move vmstats structs definition above flushing code
The following patch will make use of those structs in the flushing code, so move their definitions (and a few other dependencies) a little bit up to reduce the diff noise in the following patch. No functional change intended. Link: https://lkml.kernel.org/r/20231129032154.3710765-3-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Acked-by: Shakeel Butt <shakeelb@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yosry Ahmed
|
508bed8847 |
mm: memcg: change flush_next_time to flush_last_time
Patch series "mm: memcg: subtree stats flushing and thresholds", v4. This series attempts to address shortages in today's approach for memcg stats flushing, namely occasionally stale or expensive stat reads. The series does so by changing the threshold that we use to decide whether to trigger a flush to be per memcg instead of global (patch 3), and then changing flushing to be per memcg (i.e. subtree flushes) instead of global (patch 5). This patch (of 5): flush_next_time is an inaccurate name. It's not the next time that periodic flushing will happen, it's rather the next time that ratelimited flushing can happen if the periodic flusher is late. Simplify its semantics by just storing the timestamp of the last flush instead, flush_last_time. Move the 2*FLUSH_TIME addition to mem_cgroup_flush_stats_ratelimited(), and add a comment explaining it. This way, all the ratelimiting semantics live in one place. No functional change intended. Link: https://lkml.kernel.org/r/20231129032154.3710765-1-yosryahmed@google.com Link: https://lkml.kernel.org/r/20231129032154.3710765-2-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Chris Li <chrisl@kernel.org> (Google) Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Ivan Babrou <ivan@cloudflare.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutny <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Tejun Heo <tj@kernel.org> Cc: Waiman Long <longman@redhat.com> Cc: Wei Xu <weixugc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Domenico Cerasuolo
|
7108cc3f76 |
mm: memcg: add per-memcg zswap writeback stat
Since zswap now writes back pages from memcg-specific LRUs, we now need a new stat to show writebacks count for each memcg. [nphamcs@gmail.com: rename ZSWP_WB to ZSWPWB] Link: https://lkml.kernel.org/r/20231205193307.2432803-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231130194023.4102148-5-nphamcs@gmail.com Suggested-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Signed-off-by: Nhat Pham <nphamcs@gmail.com> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Cc: Chris Li <chrisl@kernel.org> Cc: Dan Streetman <ddstreet@ieee.org> 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: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Domenico Cerasuolo
|
a65b0e7607 |
zswap: make shrinking memcg-aware
Currently, we only have a single global LRU for zswap. This makes it impossible to perform worload-specific shrinking - an memcg cannot determine which pages in the pool it owns, and often ends up writing pages from other memcgs. This issue has been previously observed in practice and mitigated by simply disabling memcg-initiated shrinking: https://lore.kernel.org/all/20230530232435.3097106-1-nphamcs@gmail.com/T/#u This patch fully resolves the issue by replacing the global zswap LRU with memcg- and NUMA-specific LRUs, and modify the reclaim logic: a) When a store attempt hits an memcg limit, it now triggers a synchronous reclaim attempt that, if successful, allows the new hotter page to be accepted by zswap. b) If the store attempt instead hits the global zswap limit, it will trigger an asynchronous reclaim attempt, in which an memcg is selected for reclaim in a round-robin-like fashion. [nphamcs@gmail.com: use correct function for the onlineness check, use mem_cgroup_iter_break()] Link: https://lkml.kernel.org/r/20231205195419.2563217-1-nphamcs@gmail.com [nphamcs@gmail.com: drop the pool's reference at the end of the writeback step] Link: https://lkml.kernel.org/r/20231206030627.4155634-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20231130194023.4102148-4-nphamcs@gmail.com Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Co-developed-by: Nhat Pham <nphamcs@gmail.com> Signed-off-by: Nhat Pham <nphamcs@gmail.com> Tested-by: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Chris Li <chrisl@kernel.org> Cc: Dan Streetman <ddstreet@ieee.org> 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: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Dmitry Rokosov
|
664dc2189d |
mm: memcg: add reminder comment for the memcg v2 events
To maintain the correct state, it is important to ensure that events for the memory cgroup v2 are aligned with the sample cgroup codes. Link: https://lkml.kernel.org/r/20231123071945.25811-4-ddrokosov@salutedevices.com Signed-off-by: Dmitry Rokosov <ddrokosov@salutedevices.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> |
||
|
Roman Gushchin
|
5f79489a73 |
mm: kmem: properly initialize local objcg variable in current_obj_cgroup()
Erhard reported that the 6.7-rc1 kernel panics on boot if being
built with clang-16. The problem was not reproducible with gcc.
[ 5.975049] general protection fault, probably for non-canonical address 0xf555515555555557: 0000 [#1] SMP KASAN PTI
[ 5.976422] KASAN: maybe wild-memory-access in range [0xaaaaaaaaaaaaaab8-0xaaaaaaaaaaaaaabf]
[ 5.977475] CPU: 3 PID: 1 Comm: systemd Not tainted 6.7.0-rc1-Zen3 #77
[ 5.977860] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 5.977860] RIP: 0010:obj_cgroup_charge_pages+0x27/0x2d5
[ 5.977860] Code: 90 90 90 55 41 57 41 56 41 55 41 54 53 89 d5 41 89 f6 49 89 ff 48 b8 00 00 00 00 00 fc ff df 49 83 c7 10 4d3
[ 5.977860] RSP: 0018:ffffc9000001fb18 EFLAGS: 00010a02
[ 5.977860] RAX: dffffc0000000000 RBX: aaaaaaaaaaaaaaaa RCX: ffff8883eb9a8b08
[ 5.977860] RDX: 0000000000000005 RSI: 0000000000400cc0 RDI: aaaaaaaaaaaaaaaa
[ 5.977860] RBP: 0000000000000005 R08: 3333333333333333 R09: 0000000000000000
[ 5.977860] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8883eb9a8b18
[ 5.977860] R13: 1555555555555557 R14: 0000000000400cc0 R15: aaaaaaaaaaaaaaba
[ 5.977860] FS: 00007f2976438b40(0000) GS:ffff8883eb980000(0000) knlGS:0000000000000000
[ 5.977860] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 5.977860] CR2: 00007f29769e0060 CR3: 0000000107222003 CR4: 0000000000370eb0
[ 5.977860] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 5.977860] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 5.977860] Call Trace:
[ 5.977860] <TASK>
[ 5.977860] ? __die_body+0x16/0x75
[ 5.977860] ? die_addr+0x4a/0x70
[ 5.977860] ? exc_general_protection+0x1c9/0x2d0
[ 5.977860] ? cgroup_mkdir+0x455/0x9fb
[ 5.977860] ? __x64_sys_mkdir+0x69/0x80
[ 5.977860] ? asm_exc_general_protection+0x26/0x30
[ 5.977860] ? obj_cgroup_charge_pages+0x27/0x2d5
[ 5.977860] obj_cgroup_charge+0x114/0x1ab
[ 5.977860] pcpu_alloc+0x1a6/0xa65
[ 5.977860] ? mem_cgroup_css_alloc+0x1eb/0x1140
[ 5.977860] ? cgroup_apply_control_enable+0x26b/0x7c0
[ 5.977860] mem_cgroup_css_alloc+0x23f/0x1140
[ 5.977860] cgroup_apply_control_enable+0x26b/0x7c0
[ 5.977860] ? cgroup_kn_set_ugid+0x2d/0x1a0
[ 5.977860] cgroup_mkdir+0x455/0x9fb
[ 5.977860] ? __cfi_cgroup_mkdir+0x10/0x10
[ 5.977860] kernfs_iop_mkdir+0x130/0x170
[ 5.977860] vfs_mkdir+0x405/0x530
[ 5.977860] do_mkdirat+0x188/0x1f0
[ 5.977860] __x64_sys_mkdir+0x69/0x80
[ 5.977860] do_syscall_64+0x7d/0x100
[ 5.977860] ? do_syscall_64+0x89/0x100
[ 5.977860] ? do_syscall_64+0x89/0x100
[ 5.977860] ? do_syscall_64+0x89/0x100
[ 5.977860] ? do_syscall_64+0x89/0x100
[ 5.977860] entry_SYSCALL_64_after_hwframe+0x4b/0x53
[ 5.977860] RIP: 0033:0x7f297671defb
[ 5.977860] Code: 8b 05 39 7f 0d 00 bb ff ff ff ff 64 c7 00 16 00 00 00 e9 61 ff ff ff e8 23 0c 02 00 0f 1f 00 f3 0f 1e fa b88
[ 5.977860] RSP: 002b:00007ffee6242bb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000053
[ 5.977860] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f297671defb
[ 5.977860] RDX: 0000000000000000 RSI: 00000000000001ed RDI: 000055c6b449f0e0
[ 5.977860] RBP: 00007ffee6242bf0 R08: 000000000000000e R09: 0000000000000000
[ 5.977860] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c6b445db80
[ 5.977860] R13: 00000000000003a0 R14: 00007f2976a68651 R15: 00000000000003a0
[ 5.977860] </TASK>
[ 5.977860] Modules linked in:
[ 6.014095] ---[ end trace 0000000000000000 ]---
[ 6.014701] RIP: 0010:obj_cgroup_charge_pages+0x27/0x2d5
[ 6.015348] Code: 90 90 90 55 41 57 41 56 41 55 41 54 53 89 d5 41 89 f6 49 89 ff 48 b8 00 00 00 00 00 fc ff df 49 83 c7 10 4d3
[ 6.017575] RSP: 0018:ffffc9000001fb18 EFLAGS: 00010a02
[ 6.018255] RAX: dffffc0000000000 RBX: aaaaaaaaaaaaaaaa RCX: ffff8883eb9a8b08
[ 6.019120] RDX: 0000000000000005 RSI: 0000000000400cc0 RDI: aaaaaaaaaaaaaaaa
[ 6.019983] RBP: 0000000000000005 R08: 3333333333333333 R09: 0000000000000000
[ 6.020849] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8883eb9a8b18
[ 6.021747] R13: 1555555555555557 R14: 0000000000400cc0 R15: aaaaaaaaaaaaaaba
[ 6.022609] FS: 00007f2976438b40(0000) GS:ffff8883eb980000(0000) knlGS:0000000000000000
[ 6.023593] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 6.024296] CR2: 00007f29769e0060 CR3: 0000000107222003 CR4: 0000000000370eb0
[ 6.025279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 6.026139] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 6.027000] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Actually the problem is caused by uninitialized local variable in
current_obj_cgroup(). If the root memory cgroup is set as an active
memory cgroup for a charging scope (as in the trace, where systemd tries
to create the first non-root cgroup, so the parent cgroup is the root
cgroup), the "for" loop is skipped and uninitialized objcg is returned,
causing a panic down the accounting stack.
The fix is trivial: initialize the objcg variable to NULL unconditionally
before the "for" loop.
[vbabka@suse.cz: remove redundant assignment]
Link: https://lkml.kernel.org/r/4bd106d5-c3e3-6731-9a74-cff81e2392de@suse.cz
Link: https://lkml.kernel.org/r/20231116025109.3775055-1-roman.gushchin@linux.dev
Fixes:
|
||
|
Vlastimil Babka
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6011be5991 |
mm/slab: move pre/post-alloc hooks from slab.h to slub.c
We don't share the hooks between two slab implementations anymore so they can be moved away from the header. As part of the move, also move should_failslab() from slab_common.c as the pre_alloc hook uses it. This means slab.h can stop including fault-inject.h and kmemleak.h. Fix up some files that were depending on the includes transitively. Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: David Rientjes <rientjes@google.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Vlastimil Babka
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bc3dcb850f |
mm/memcontrol: remove CONFIG_SLAB #ifdef guards
With SLAB removed, these are never true anymore so we can clean up. Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Tested-by: David Rientjes <rientjes@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Christian Brauner
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3652117f85 |
eventfd: simplify eventfd_signal()
Ever since the eventfd type was introduced back in 2007 in commit
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Roman Gushchin
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24948e3b7b |
mm: kmem: drop __GFP_NOFAIL when allocating objcg vectors
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> |
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Muhammad Muzammil
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be16dd764a |
mm: fix multiple typos in multiple files
Link: https://lkml.kernel.org/r/20231023124405.36981-1-m.muzzammilashraf@gmail.com Signed-off-by: Muhammad Muzammil <m.muzzammilashraf@gmail.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muhammad Muzammil <m.muzzammilashraf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Roman Gushchin
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e56808fef8 |
mm: kmem: reimplement get_obj_cgroup_from_current()
Reimplement get_obj_cgroup_from_current() using current_obj_cgroup(). get_obj_cgroup_from_current() and current_obj_cgroup() share 80% of the code, so the new implementation is almost trivial. get_obj_cgroup_from_current() is a convenient function used by the bpf subsystem, so there is no reason to get rid of it completely. Link: https://lkml.kernel.org/r/20231019225346.1822282-7-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Shakeel Butt <shakeelb@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Roman Gushchin
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e86828e544 |
mm: kmem: scoped objcg protection
Switch to a scope-based protection of the objcg pointer on slab/kmem allocation paths. Instead of using the get_() semantics in the pre-allocation hook and put the reference afterwards, let's rely on the fact that objcg is pinned by the scope. It's possible because: 1) if the objcg is received from the current task struct, the task is keeping a reference to the objcg. 2) if the objcg is received from an active memcg (remote charging), the memcg is pinned by the scope and has a reference to the corresponding objcg. Link: https://lkml.kernel.org/r/20231019225346.1822282-5-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Acked-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Roman Gushchin
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675d6c9b59 |
mm: kmem: make memcg keep a reference to the original objcg
Keep a reference to the original objcg object for the entire life of a memcg structure. This allows to simplify the synchronization on the kernel memory allocation paths: pinning a (live) memcg will also pin the corresponding objcg. The memory overhead of this change is minimal because object cgroups usually outlive their corresponding memory cgroups even without this change, so it's only an additional pointer per memcg. Link: https://lkml.kernel.org/r/20231019225346.1822282-4-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Acked-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Roman Gushchin
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1aacbd3543 |
mm: kmem: add direct objcg pointer to task_struct
To charge a freshly allocated kernel object to a memory cgroup, the kernel
needs to obtain an objcg pointer. Currently it does it indirectly by
obtaining the memcg pointer first and then calling to
__get_obj_cgroup_from_memcg().
Usually tasks spend their entire life belonging to the same object cgroup.
So it makes sense to save the objcg pointer on task_struct directly, so
it can be obtained faster. It requires some work on fork, exit and cgroup
migrate paths, but these paths are way colder.
To avoid any costly synchronization the following rules are applied:
1) A task sets it's objcg pointer itself.
2) If a task is being migrated to another cgroup, the least
significant bit of the objcg pointer is set atomically.
3) On the allocation path the objcg pointer is obtained locklessly
using the READ_ONCE() macro and the least significant bit is
checked. If it's set, the following procedure is used to update
it locklessly:
- task->objcg is zeroed using cmpxcg
- new objcg pointer is obtained
- task->objcg is updated using try_cmpxchg
- operation is repeated if try_cmpxcg fails
It guarantees that no updates will be lost if task migration
is racing against objcg pointer update. It also allows to keep
both read and write paths fully lockless.
Because the task is keeping a reference to the objcg, it can't go away
while the task is alive.
This commit doesn't change the way the remote memcg charging works.
Link: https://lkml.kernel.org/r/20231019225346.1822282-3-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Roman Gushchin
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7d0715d0d6 |
mm: kmem: optimize get_obj_cgroup_from_current()
Patch series "mm: improve performance of accounted kernel memory allocations", v5. This patchset improves the performance of accounted kernel memory allocations by ~30% as measured by a micro-benchmark [1]. The benchmark is very straightforward: 1M of 64 bytes-large kmalloc() allocations. Below are results with the disabled kernel memory accounting, the original state and with this patchset applied. | | Kmem disabled | Original | Patched | Delta | |-------------+---------------+----------+---------+--------| | User cgroup | 29764 | 84548 | 59078 | -30.0% | | Root cgroup | 29742 | 48342 | 31501 | -34.8% | As we can see, the patchset removes the majority of the overhead when there is no actual accounting (a task belongs to the root memory cgroup) and almost halves the accounting overhead otherwise. The main idea is to get rid of unnecessary memcg to objcg conversions and switch to a scope-based protection of objcgs, which eliminates extra operations with objcg reference counters under a rcu read lock. More details are provided in individual commit descriptions. This patch (of 5): Manually inline memcg_kmem_bypass() and active_memcg() to speed up get_obj_cgroup_from_current() by avoiding duplicate in_task() checks and active_memcg() readings. Also add a likely() macro to __get_obj_cgroup_from_memcg(): obj_cgroup_tryget() should succeed at almost all times except a very unlikely race with the memcg deletion path. Link: https://lkml.kernel.org/r/20231019225346.1822282-1-roman.gushchin@linux.dev Link: https://lkml.kernel.org/r/20231019225346.1822282-2-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Acked-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Nhat Pham
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8cba9576df |
hugetlb: memcg: account hugetlb-backed memory in memory controller
Currently, hugetlb memory usage is not acounted for in the memory
controller, which could lead to memory overprotection for cgroups with
hugetlb-backed memory. This has been observed in our production system.
For instance, here is one of our usecases: suppose there are two 32G
containers. The machine is booted with hugetlb_cma=6G, and each container
may or may not use up to 3 gigantic page, depending on the workload within
it. The rest is anon, cache, slab, etc. We can set the hugetlb cgroup
limit of each cgroup to 3G to enforce hugetlb fairness. But it is very
difficult to configure memory.max to keep overall consumption, including
anon, cache, slab etc. fair.
What we have had to resort to is to constantly poll hugetlb usage and
readjust memory.max. Similar procedure is done to other memory limits
(memory.low for e.g). However, this is rather cumbersome and buggy.
Furthermore, when there is a delay in memory limits correction, (for e.g
when hugetlb usage changes within consecutive runs of the userspace
agent), the system could be in an over/underprotected state.
This patch rectifies this issue by charging the memcg when the hugetlb
folio is utilized, and uncharging when the folio is freed (analogous to
the hugetlb controller). Note that we do not charge when the folio is
allocated to the hugetlb pool, because at this point it is not owned by
any memcg.
Some caveats to consider:
* This feature is only available on cgroup v2.
* There is no hugetlb pool management involved in the memory
controller. As stated above, hugetlb folios are only charged towards
the memory controller when it is used. Host overcommit management
has to consider it when configuring hard limits.
* Failure to charge towards the memcg results in SIGBUS. This could
happen even if the hugetlb pool still has pages (but the cgroup
limit is hit and reclaim attempt fails).
* When this feature is enabled, hugetlb pages contribute to memory
reclaim protection. low, min limits tuning must take into account
hugetlb memory.
* Hugetlb pages utilized while this option is not selected will not
be tracked by the memory controller (even if cgroup v2 is remounted
later on).
Link: https://lkml.kernel.org/r/20231006184629.155543-4-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frank van der Linden <fvdl@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Tejun heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Nhat Pham
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85ce2c517a |
memcontrol: only transfer the memcg data for migration
For most migration use cases, only transfer the memcg data from the old folio to the new folio, and clear the old folio's memcg data. No charging and uncharging will be done. This shaves off some work on the migration path, and avoids the temporary double charging of a folio during its migration. The only exception is replace_page_cache_folio(), which will use the old mem_cgroup_migrate() (now renamed to mem_cgroup_replace_folio). In that context, the isolation of the old page isn't quite as thorough as with migration, so we cannot use our new implementation directly. This patch is the result of the following discussion on the new hugetlb memcg accounting behavior: https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ Link: https://lkml.kernel.org/r/20231006184629.155543-3-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Frank van der Linden <fvdl@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Tejun heo <tj@kernel.org> Cc: Yosry Ahmed <yosryahmed@google.com> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |