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2022-04-15mm, kfence: support kmem_dump_obj() for KFENCE objectsMarco Elver1-1/+1
Calling kmem_obj_info() via kmem_dump_obj() on KFENCE objects has been producing garbage data due to the object not actually being maintained by SLAB or SLUB. Fix this by implementing __kfence_obj_info() that copies relevant information to struct kmem_obj_info when the object was allocated by KFENCE; this is called by a common kmem_obj_info(), which also calls the slab/slub/slob specific variant now called __kmem_obj_info(). For completeness, kmem_dump_obj() now displays if the object was allocated by KFENCE. Link: https://lore.kernel.org/all/20220323090520.GG16885@xsang-OptiPlex-9020/ Link: https://lkml.kernel.org/r/20220406131558.3558585-1-elver@google.com Fixes: b89fb5ef0ce6 ("mm, kfence: insert KFENCE hooks for SLUB") Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB") Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reported-by: kernel test robot <oliver.sang@intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> [slab] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-23Merge tag 'slab-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slabLinus Torvalds1-78/+52
Pull slab updates from Vlastimil Babka: - A few non-trivial SLUB code cleanups, most notably a refactoring of deactivate_slab(). - A bunch of trivial changes, such as removal of unused parameters, making stuff static, and employing helper functions. * tag 'slab-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: mm: slub: Delete useless parameter of alloc_slab_page() mm: slab: Delete unused SLAB_DEACTIVATED flag mm/slub: remove forced_order parameter in calculate_sizes mm/slub: refactor deactivate_slab() mm/slub: limit number of node partial slabs only in cache creation mm/slub: use helper macro __ATTR_XX_MODE for SLAB_ATTR(_RO) mm/slab_common: use helper function is_power_of_2() mm/slob: make kmem_cache_boot static
2022-03-22mm: introduce kmem_cache_alloc_lruMuchun Song1-14/+28
We currently allocate scope for every memcg to be able to tracked on every superblock instantiated in the system, regardless of whether that superblock is even accessible to that memcg. These huge memcg counts come from container hosts where memcgs are confined to just a small subset of the total number of superblocks that instantiated at any given point in time. For these systems with huge container counts, list_lru does not need the capability of tracking every memcg on every superblock. What it comes down to is that adding the memcg to the list_lru at the first insert. So introduce kmem_cache_alloc_lru to allocate objects and its list_lru. In the later patch, we will convert all inode and dentry allocation from kmem_cache_alloc to kmem_cache_alloc_lru. Link: https://lkml.kernel.org/r/20220228122126.37293-3-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Cc: Alex Shi <alexs@kernel.org> Cc: Anna Schumaker <Anna.Schumaker@Netapp.com> Cc: Chao Yu <chao@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Fam Zheng <fam.zheng@bytedance.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kari Argillander <kari.argillander@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Xiongchun Duan <duanxiongchun@bytedance.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-21Merge branch 'slab/for-5.18/cleanups' into slab/for-linusVlastimil Babka1-63/+42
Non-trivial SLUB code cleanups, notably refactoring of deactivate_slab().
2022-03-10mm: slub: Delete useless parameter of alloc_slab_page()Xiongwei Song1-4/+4
The parameter @s is useless for alloc_slab_page(). It was added in 2014 by commit 5dfb41750992 ("sl[au]b: charge slabs to kmemcg explicitly"). The need for it was removed in 2020 by commit 1f3147b49d75 ("mm: slub: call account_slab_page() after slab page initialization"). Let's delete it. [willy@infradead.org: Added detailed history of @s] Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20220310140701.87908-3-sxwjean@me.com
2022-03-09mm/slub: remove forced_order parameter in calculate_sizesMiaohe Lin1-7/+4
Since commit 32a6f409b693 ("mm, slub: remove runtime allocation order changes"), forced_order is always -1. Remove this unneeded parameter to simplify the code. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20220309092036.50844-1-linmiaohe@huawei.com
2022-03-09mm/slub: refactor deactivate_slab()Hyeonggon Yoo1-52/+39
Simplify deactivate_slab() by unlocking n->list_lock and retrying cmpxchg_double() when cmpxchg_double() fails, and perform add_{partial,full} only when it succeed. Releasing and taking n->list_lock again here is not harmful as SLUB avoids deactivating slabs as much as possible. [ vbabka@suse.cz: perform add_{partial,full} when cmpxchg_double() succeed. count deactivating full slabs even if debugging flag is not set. ] Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20220307074057.902222-3-42.hyeyoo@gmail.com
2022-03-09mm/slub: limit number of node partial slabs only in cache creationHyeonggon Yoo1-11/+3
SLUB sets number of minimum partial slabs for node (min_partial) using set_min_partial(). SLUB holds at least min_partial slabs even if they're empty to avoid excessive use of page allocator. set_min_partial() limits value of min_partial limits value of min_partial MIN_PARTIAL and MAX_PARTIAL. As set_min_partial() can be called by min_partial_store() too, Only limit value of min_partial in kmem_cache_open() so that it can be changed to value that a user wants. [ rientjes@google.com: Fold set_min_partial() into its callers ] Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20220307074057.902222-2-42.hyeyoo@gmail.com
2022-03-07mm/slub: use helper macro __ATTR_XX_MODE for SLAB_ATTR(_RO)Lianjie Zhang1-4/+2
This allows more concise code, and VERIFY_OCTAL_PERMISSIONS() can help validate any future change. Signed-off-by: Lianjie Zhang <zhanglianjie@uniontech.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Link: https://lore.kernel.org/r/20220306073818.15089-1-zhanglianjie@uniontech.com
2022-01-06mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabledVlastimil Babka1-2/+6
The fields 'next' and 'slabs' are only used when CONFIG_SLUB_CPU_PARTIAL is enabled. We can put their definition to #ifdef to prevent accidental use when disabled. Currenlty show_slab_objects() and slabs_cpu_partial_show() contain code accessing the slabs field that's effectively dead with CONFIG_SLUB_CPU_PARTIAL=n through the wrappers slub_percpu_partial() and slub_percpu_partial_read_once(), but to prevent a compile error, we need to hide all this code behind #ifdef. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
2022-01-06mm/kasan: Convert to struct folio and struct slabMatthew Wilcox (Oracle)1-1/+1
KASAN accesses some slab related struct page fields so we need to convert it to struct slab. Some places are a bit simplified thanks to kasan_addr_to_slab() encapsulating the PageSlab flag check through virt_to_slab(). When resolving object address to either a real slab or a large kmalloc, use struct folio as the intermediate type for testing the slab flag to avoid unnecessary implicit compound_head(). [ vbabka@suse.cz: use struct folio, adjust to differences in previous patches ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Tested-by: Hyeongogn Yoo <42.hyeyoo@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: <kasan-dev@googlegroups.com>
2022-01-06mm: Convert struct page to struct slab in functions used by other subsystemsVlastimil Babka1-1/+1
KASAN, KFENCE and memcg interact with SLAB or SLUB internals through functions nearest_obj(), obj_to_index() and objs_per_slab() that use struct page as parameter. This patch converts it to struct slab including all callers, through a coccinelle semantic patch. // Options: --include-headers --no-includes --smpl-spacing include/linux/slab_def.h include/linux/slub_def.h mm/slab.h mm/kasan/*.c mm/kfence/kfence_test.c mm/memcontrol.c mm/slab.c mm/slub.c // Note: needs coccinelle 1.1.1 to avoid breaking whitespace @@ @@ -objs_per_slab_page( +objs_per_slab( ... ) { ... } @@ @@ -objs_per_slab_page( +objs_per_slab( ... ) @@ identifier fn =~ "obj_to_index|objs_per_slab"; @@ fn(..., - const struct page *page + const struct slab *slab ,...) { <... ( - page_address(page) + slab_address(slab) | - page + slab ) ...> } @@ identifier fn =~ "nearest_obj"; @@ fn(..., - struct page *page + const struct slab *slab ,...) { <... ( - page_address(page) + slab_address(slab) | - page + slab ) ...> } @@ identifier fn =~ "nearest_obj|obj_to_index|objs_per_slab"; expression E; @@ fn(..., ( - slab_page(E) + E | - virt_to_page(E) + virt_to_slab(E) | - virt_to_head_page(E) + virt_to_slab(E) | - page + page_slab(page) ) ,...) Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: <kasan-dev@googlegroups.com> Cc: <cgroups@vger.kernel.org>
2022-01-06mm/slub: Finish struct page to struct slab conversionVlastimil Babka1-53/+52
Update comments mentioning pages to mention slabs where appropriate. Also some goto labels. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm/slub: Convert most struct page to struct slab by spatchVlastimil Babka1-436/+436
The majority of conversion from struct page to struct slab in SLUB internals can be delegated to a coccinelle semantic patch. This includes renaming of variables with 'page' in name to 'slab', and similar. Big thanks to Julia Lawall and Luis Chamberlain for help with coccinelle. // Options: --include-headers --no-includes --smpl-spacing include/linux/slub_def.h mm/slub.c // Note: needs coccinelle 1.1.1 to avoid breaking whitespace, and ocaml for the // embedded script // build list of functions to exclude from applying the next rule @initialize:ocaml@ @@ let ok_function p = not (List.mem (List.hd p).current_element ["nearest_obj";"obj_to_index";"objs_per_slab_page";"__slab_lock";"__slab_unlock";"free_nonslab_page";"kmalloc_large_node"]) // convert the type from struct page to struct page in all functions except the // list from previous rule // this also affects struct kmem_cache_cpu, but that's ok @@ position p : script:ocaml() { ok_function p }; @@ - struct page@p + struct slab // in struct kmem_cache_cpu, change the name from page to slab // the type was already converted by the previous rule @@ @@ struct kmem_cache_cpu { ... -struct slab *page; +struct slab *slab; ... } // there are many places that use c->page which is now c->slab after the // previous rule @@ struct kmem_cache_cpu *c; @@ -c->page +c->slab @@ @@ struct kmem_cache { ... - unsigned int cpu_partial_pages; + unsigned int cpu_partial_slabs; ... } @@ struct kmem_cache *s; @@ - s->cpu_partial_pages + s->cpu_partial_slabs @@ @@ static void - setup_page_debug( + setup_slab_debug( ...) {...} @@ @@ - setup_page_debug( + setup_slab_debug( ...); // for all functions (with exceptions), change any "struct slab *page" // parameter to "struct slab *slab" in the signature, and generally all // occurences of "page" to "slab" in the body - with some special cases. @@ identifier fn !~ "free_nonslab_page|obj_to_index|objs_per_slab_page|nearest_obj"; @@ fn(..., - struct slab *page + struct slab *slab ,...) { <... - page + slab ...> } // similar to previous but the param is called partial_page @@ identifier fn; @@ fn(..., - struct slab *partial_page + struct slab *partial_slab ,...) { <... - partial_page + partial_slab ...> } // similar to previous but for functions that take pointer to struct page ptr @@ identifier fn; @@ fn(..., - struct slab **ret_page + struct slab **ret_slab ,...) { <... - ret_page + ret_slab ...> } // functions converted by previous rules that were temporarily called using // slab_page(E) so we want to remove the wrapper now that they accept struct // slab ptr directly @@ identifier fn =~ "slab_free|do_slab_free"; expression E; @@ fn(..., - slab_page(E) + E ,...) // similar to previous but for another pattern @@ identifier fn =~ "slab_pad_check|check_object"; @@ fn(..., - folio_page(folio, 0) + slab ,...) // functions that were returning struct page ptr and now will return struct // slab ptr, including slab_page() wrapper removal @@ identifier fn =~ "allocate_slab|new_slab"; expression E; @@ static -struct slab * +struct slab * fn(...) { <... - slab_page(E) + E ...> } // rename any former struct page * declarations @@ @@ struct slab * ( - page + slab | - partial_page + partial_slab | - oldpage + oldslab ) ; // this has to be separate from previous rule as page and page2 appear at the // same line @@ @@ struct slab * -page2 +slab2 ; // similar but with initial assignment @@ expression E; @@ struct slab * ( - page + slab | - flush_page + flush_slab | - discard_page + slab_to_discard | - page_to_unfreeze + slab_to_unfreeze ) = E; // convert most of struct page to struct slab usage inside functions (with // exceptions), including specific variable renames @@ identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node"; expression E; @@ fn(...) { <... ( - int pages; + int slabs; | - int pages = E; + int slabs = E; | - page + slab | - flush_page + flush_slab | - partial_page + partial_slab | - oldpage->pages + oldslab->slabs | - oldpage + oldslab | - unsigned int nr_pages; + unsigned int nr_slabs; | - nr_pages + nr_slabs | - unsigned int partial_pages = E; + unsigned int partial_slabs = E; | - partial_pages + partial_slabs ) ...> } // this has to be split out from the previous rule so that lines containing // multiple matching changes will be fully converted @@ identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node"; @@ fn(...) { <... ( - slab->pages + slab->slabs | - pages + slabs | - page2 + slab2 | - discard_page + slab_to_discard | - page_to_unfreeze + slab_to_unfreeze ) ...> } // after we simply changed all occurences of page to slab, some usages need // adjustment for slab-specific functions, or use slab_page() wrapper @@ identifier fn !~ "nearest_obj|obj_to_index|objs_per_slab_page|__slab_(un)*lock|__free_slab|free_nonslab_page|kmalloc_large_node"; @@ fn(...) { <... ( - page_slab(slab) + slab | - kasan_poison_slab(slab) + kasan_poison_slab(slab_page(slab)) | - page_address(slab) + slab_address(slab) | - page_size(slab) + slab_size(slab) | - PageSlab(slab) + folio_test_slab(slab_folio(slab)) | - page_to_nid(slab) + slab_nid(slab) | - compound_order(slab) + slab_order(slab) ) ...> } Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Luis Chamberlain <mcgrof@kernel.org>
2022-01-06mm/slub: Convert pfmemalloc_match() to take a struct slabMatthew Wilcox (Oracle)1-19/+6
Preparatory for mass conversion. Use the new slab_test_pfmemalloc() helper. As it doesn't do VM_BUG_ON(!PageSlab()) we no longer need the pfmemalloc_match_unsafe() variant. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
2022-01-06mm/slub: Convert __free_slab() to use struct slabVlastimil Babka1-14/+13
__free_slab() is on the boundary of distinguishing struct slab and struct page so start with struct slab but convert to folio for working with flags and folio_page() to call functions that require struct page. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
2022-01-06mm/slub: Convert alloc_slab_page() to return a struct slabVlastimil Babka1-10/+16
Preparatory, callers convert back to struct page for now. Also move setting page flags to alloc_slab_page() where we still operate on a struct page. This means the page->slab_cache pointer is now set later than the PageSlab flag, which could theoretically confuse some pfn walker assuming PageSlab means there would be a valid cache pointer. But as the code had no barriers and used __set_bit() anyway, it could have happened already, so there shouldn't be such a walker. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
2022-01-06mm/slub: Convert print_page_info() to print_slab_info()Matthew Wilcox (Oracle)1-6/+7
Improve the type safety and prepare for further conversion. For flags access, convert to folio internally. [ vbabka@suse.cz: access flags via folio_flags() ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
2022-01-06mm/slub: Convert __slab_lock() and __slab_unlock() to struct slabVlastimil Babka1-7/+11
These functions operate on the PG_locked page flag, but make them accept struct slab to encapsulate this implementation detail. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm/slub: Convert kfree() to use a struct slabMatthew Wilcox (Oracle)1-13/+16
Convert kfree(), kmem_cache_free() and ___cache_free() to resolve object addresses to struct slab, using folio as intermediate step where needed. Keep passing the result as struct page for now in preparation for mass conversion of internal functions. [ vbabka@suse.cz: Use folio as intermediate step when checking for large kmalloc pages, and when freeing them - rename free_nonslab_page() to free_large_kmalloc() that takes struct folio ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm/slub: Convert detached_freelist to use a struct slabMatthew Wilcox (Oracle)1-14/+17
This gives us a little bit of extra typesafety as we know that nobody called virt_to_page() instead of virt_to_head_page(). [ vbabka@suse.cz: Use folio as intermediate step when filtering out large kmalloc pages ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm: Convert check_heap_object() to use struct slabMatthew Wilcox (Oracle)1-5/+5
Ensure that we're not seeing a tail page inside __check_heap_object() by converting to a slab instead of a page. Take the opportunity to mark the slab as const since we're not modifying it. Also move the declaration of __check_heap_object() to mm/slab.h so it's not available to the wider kernel. [ vbabka@suse.cz: in check_heap_object() only convert to struct slab for actual PageSlab pages; use folio as intermediate step instead of page ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm: Use struct slab in kmem_obj_info()Matthew Wilcox (Oracle)1-6/+7
All three implementations of slab support kmem_obj_info() which reports details of an object allocated from the slab allocator. By using the slab type instead of the page type, we make it obvious that this can only be called for slabs. [ vbabka@suse.cz: also convert the related kmem_valid_obj() to folios ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm: Convert __ksize() to struct slabMatthew Wilcox (Oracle)1-7/+5
In SLUB, use folios, and struct slab to access slab_cache field. In SLOB, use folios to properly resolve pointers beyond PAGE_SIZE offset of the object. [ vbabka@suse.cz: use folios, and only convert folio_test_slab() == true folios to struct slab ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm: Convert [un]account_slab_page() to struct slabMatthew Wilcox (Oracle)1-2/+2
Convert the parameter of these functions to struct slab instead of struct page and drop _page from the names. For now their callers just convert page to slab. [ vbabka@suse.cz: replace existing functions instead of calling them ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm: Split slab into its own typeMatthew Wilcox (Oracle)1-4/+4
Make struct slab independent of struct page. It still uses the underlying memory in struct page for storing slab-specific data, but slab and slub can now be weaned off using struct page directly. Some of the wrapper functions (slab_address() and slab_order()) still need to cast to struct folio, but this is a significant disentanglement. [ vbabka@suse.cz: Rebase on folios, use folio instead of page where possible. Do not duplicate flags field in struct slab, instead make the related accessors go through slab_folio(). For testing pfmemalloc use the folio_*_active flag accessors directly so the PageSlabPfmemalloc wrappers can be removed later. Make folio_slab() expect only folio_test_slab() == true folios and virt_to_slab() return NULL when folio_test_slab() == false. Move struct slab to mm/slab.h. Don't represent with struct slab pages that are not true slab pages, but just a compound page obtained directly rom page allocator (with large kmalloc() for SLUB and SLOB). ] Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Roman Gushchin <guro@fb.com>
2022-01-06mm/slub: Make object_err() staticVlastimil Babka1-15/+15
There are no callers outside of mm/slub.c anymore. Move freelist_corrupted() that calls object_err() to avoid a need for forward declaration. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Roman Gushchin <guro@fb.com>
2021-12-10mm/slub: fix endianness bug for alloc/free_traces attributesGerald Schaefer1-6/+9
On big-endian s390, the alloc/free_traces attributes produce endless output, because of always 0 idx in slab_debugfs_show(). idx is de-referenced from *v, which points to a loff_t value, with unsigned int idx = *(unsigned int *)v; This will only give the upper 32 bits on big-endian, which remain 0. Instead of only fixing this de-reference, during discussion it seemed more appropriate to change the seq_ops so that they use an explicit iterator in private loc_track struct. This patch adds idx to loc_track, which will also fix the endianness bug. Link: https://lore.kernel.org/r/20211117193932.4049412-1-gerald.schaefer@linux.ibm.com Link: https://lkml.kernel.org/r/20211126171848.17534-1-gerald.schaefer@linux.ibm.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reported-by: Steffen Maier <maier@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-20mm: emit the "free" trace report before freeing memory in kmem_cache_free()Yunfeng Ye1-1/+1
After the memory is freed, it can be immediately allocated by other CPUs, before the "free" trace report has been emitted. This causes inaccurate traces. For example, if the following sequence of events occurs: CPU 0 CPU 1 (1) alloc xxxxxx (2) free xxxxxx (3) alloc xxxxxx (4) free xxxxxx Then they will be inaccurately reported via tracing, so that they appear to have happened in this order: CPU 0 CPU 1 (1) alloc xxxxxx (2) alloc xxxxxx (3) free xxxxxx (4) free xxxxxx This makes it look like CPU 1 somehow managed to allocate memory that CPU 0 still had allocated for itself. In order to avoid this, emit the "free xxxxxx" tracing report just before the actual call to free the memory, instead of just after it. Link: https://lkml.kernel.org/r/374eb75d-7404-8721-4e1e-65b0e5b17279@huawei.com Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-06Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-46/+63
Merge misc updates from Andrew Morton: "257 patches. Subsystems affected by this patch series: scripts, ocfs2, vfs, and mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache, gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools, memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm, vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram, cleanups, kfence, and damon)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits) mm/damon: remove return value from before_terminate callback mm/damon: fix a few spelling mistakes in comments and a pr_debug message mm/damon: simplify stop mechanism Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions Docs/admin-guide/mm/damon/start: simplify the content Docs/admin-guide/mm/damon/start: fix a wrong link Docs/admin-guide/mm/damon/start: fix wrong example commands mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on mm/damon: remove unnecessary variable initialization Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM) selftests/damon: support watermarks mm/damon/dbgfs: support watermarks mm/damon/schemes: activate schemes based on a watermarks mechanism tools/selftests/damon: update for regions prioritization of schemes mm/damon/dbgfs: support prioritization weights mm/damon/vaddr,paddr: support pageout prioritization mm/damon/schemes: prioritize regions within the quotas mm/damon/selftests: support schemes quotas mm/damon/dbgfs: support quotas of schemes ...
2021-11-06mm: remove HARDENED_USERCOPY_FALLBACKStephen Kitt1-14/+0
This has served its purpose and is no longer used. All usercopy violations appear to have been handled by now, any remaining instances (or new bugs) will cause copies to be rejected. This isn't a direct revert of commit 2d891fbc3bb6 ("usercopy: Allow strict enforcement of whitelists"); since usercopy_fallback is effectively 0, the fallback handling is removed too. This also removes the usercopy_fallback module parameter on slab_common. Link: https://github.com/KSPP/linux/issues/153 Link: https://lkml.kernel.org/r/20210921061149.1091163-1-steve@sk2.org Signed-off-by: Stephen Kitt <steve@sk2.org> Suggested-by: Kees Cook <keescook@chromium.org> Acked-by: Kees Cook <keescook@chromium.org> Reviewed-by: Joel Stanley <joel@jms.id.au> [defconfig change] Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: James Morris <jmorris@namei.org> Cc: "Serge E . Hallyn" <serge@hallyn.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-06mm, slub: use prefetchw instead of prefetchHyeonggon Yoo1-1/+1
Commit 0ad9500e16fe ("slub: prefetch next freelist pointer in slab_alloc()") introduced prefetch_freepointer() because when other cpu(s) freed objects into a page that current cpu owns, the freelist link is hot on cpu(s) which freed objects and possibly very cold on current cpu. But if freelist link chain is hot on cpu(s) which freed objects, it's better to invalidate that chain because they're not going to access again within a short time. So use prefetchw instead of prefetch. On supported architectures like x86 and arm, it invalidates other copied instances of a cache line when prefetching it. Before: Time: 91.677 Performance counter stats for 'hackbench -g 100 -l 10000': 1462938.07 msec cpu-clock # 15.908 CPUs utilized 18072550 context-switches # 12.354 K/sec 1018814 cpu-migrations # 696.416 /sec 104558 page-faults # 71.471 /sec 1580035699271 cycles # 1.080 GHz (54.51%) 2003670016013 instructions # 1.27 insn per cycle (54.31%) 5702204863 branch-misses (54.28%) 643368500985 cache-references # 439.778 M/sec (54.26%) 18475582235 cache-misses # 2.872 % of all cache refs (54.28%) 642206796636 L1-dcache-loads # 438.984 M/sec (46.87%) 18215813147 L1-dcache-load-misses # 2.84% of all L1-dcache accesses (46.83%) 653842996501 dTLB-loads # 446.938 M/sec (46.63%) 3227179675 dTLB-load-misses # 0.49% of all dTLB cache accesses (46.85%) 537531951350 iTLB-loads # 367.433 M/sec (54.33%) 114750630 iTLB-load-misses # 0.02% of all iTLB cache accesses (54.37%) 630135543177 L1-icache-loads # 430.733 M/sec (46.80%) 22923237620 L1-icache-load-misses # 3.64% of all L1-icache accesses (46.76%) 91.964452802 seconds time elapsed 43.416742000 seconds user 1422.441123000 seconds sys After: Time: 90.220 Performance counter stats for 'hackbench -g 100 -l 10000': 1437418.48 msec cpu-clock # 15.880 CPUs utilized 17694068 context-switches # 12.310 K/sec 958257 cpu-migrations # 666.651 /sec 100604 page-faults # 69.989 /sec 1583259429428 cycles # 1.101 GHz (54.57%) 2004002484935 instructions # 1.27 insn per cycle (54.37%) 5594202389 branch-misses (54.36%) 643113574524 cache-references # 447.409 M/sec (54.39%) 18233791870 cache-misses # 2.835 % of all cache refs (54.37%) 640205852062 L1-dcache-loads # 445.386 M/sec (46.75%) 17968160377 L1-dcache-load-misses # 2.81% of all L1-dcache accesses (46.79%) 651747432274 dTLB-loads # 453.415 M/sec (46.59%) 3127124271 dTLB-load-misses # 0.48% of all dTLB cache accesses (46.75%) 535395273064 iTLB-loads # 372.470 M/sec (54.38%) 113500056 iTLB-load-misses # 0.02% of all iTLB cache accesses (54.35%) 628871845924 L1-icache-loads # 437.501 M/sec (46.80%) 22585641203 L1-icache-load-misses # 3.59% of all L1-icache accesses (46.79%) 90.514819303 seconds time elapsed 43.877656000 seconds user 1397.176001000 seconds sys Link: https://lkml.org/lkml/2021/10/8/598=20 Link: https://lkml.kernel.org/r/20211011144331.70084-1-42.hyeyoo@gmail.com Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-06mm/slub: increase default cpu partial list sizesVlastimil Babka1-4/+4
The defaults are determined based on object size and can go up to 30 for objects smaller than 256 bytes. Before the previous patch changed the accounting, this could have made cpu partial list contain up to 30 pages. After that patch, only up to 2 pages with default allocation order. Very short lists limit the usefulness of the whole concept of cpu partial lists, so this patch aims at a more reasonable default under the new accounting. The defaults are quadrupled, except for object size >= PAGE_SIZE where it's doubled. This makes the lists grow up to 10 pages in practice. A quick test of booting a kernel under virtme with 4GB RAM and 8 vcpus shows the following slab memory usage after boot: Before previous patch (using page->pobjects): Slab: 36732 kB SReclaimable: 14836 kB SUnreclaim: 21896 kB After previous patch (using page->pages): Slab: 34720 kB SReclaimable: 13716 kB SUnreclaim: 21004 kB After this patch (using page->pages, higher defaults): Slab: 35252 kB SReclaimable: 13944 kB SUnreclaim: 21308 kB In the same setup, I also ran 5 times: hackbench -l 16000 -g 16 Differences in time were in the noise, we can compare slub stats as given by slabinfo -r skbuff_head_cache (the other cache heavily used by hackbench, kmalloc-cg-512 looks similar). Negligible stats left out for brevity. Before previous patch (using page->pobjects): Objects: 1408, Memory Total: 401408 Used : 304128 Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 469952498 5946606 91 1 Slowpath 42053573 506059465 8 98 Page Alloc 41093 41044 0 0 Add partial 18 21229327 0 4 Remove partial 20039522 36051 3 0 Cpu partial list 4686640 24767229 0 4 RemoteObj/SlabFrozen 16 124027841 0 24 Total 512006071 512006071 Flushes 18 Slab Deactivation Occurrences % ------------------------------------------------- Slab empty 4993 0% Deactivation bypass 24767229 99% Refilled from foreign frees 21972674 88% After previous patch (using page->pages): Objects: 480, Memory Total: 131072 Used : 103680 Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 473016294 5405653 92 1 Slowpath 38989777 506600418 7 98 Page Alloc 32717 32701 0 0 Add partial 3 22749164 0 4 Remove partial 11371127 32474 2 0 Cpu partial list 11686226 23090059 2 4 RemoteObj/SlabFrozen 2 67541803 0 13 Total 512006071 512006071 Flushes 3 Slab Deactivation Occurrences % ------------------------------------------------- Slab empty 227 0% Deactivation bypass 23090059 99% Refilled from foreign frees 27585695 119% After this patch (using page->pages, higher defaults): Objects: 896, Memory Total: 229376 Used : 193536 Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 473799295 4980278 92 0 Slowpath 38206776 507025793 7 99 Page Alloc 32295 32267 0 0 Add partial 11 23291143 0 4 Remove partial 5815764 31278 1 0 Cpu partial list 18119280 23967320 3 4 RemoteObj/SlabFrozen 10 76974794 0 15 Total 512006071 512006071 Flushes 11 Slab Deactivation Occurrences % ------------------------------------------------- Slab empty 989 0% Deactivation bypass 23967320 99% Refilled from foreign frees 32358473 135% As expected, memory usage dropped significantly with change of accounting, increasing the defaults increased it, but not as much. The number of page allocation/frees dropped significantly with the new accounting, but didn't increase with the higher defaults. Interestingly, the number of fasthpath allocations increased, as well as allocations from the cpu partial list, even though it's shorter. Link: https://lkml.kernel.org/r/20211012134651.11258-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Jann Horn <jannh@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-06mm, slub: change percpu partial accounting from objects to pagesVlastimil Babka1-30/+59
With CONFIG_SLUB_CPU_PARTIAL enabled, SLUB keeps a percpu list of partial slabs that can be promoted to cpu slab when the previous one is depleted, without accessing the shared partial list. A slab can be added to this list by 1) refill of an empty list from get_partial_node() - once we really have to access the shared partial list, we acquire multiple slabs to amortize the cost of locking, and 2) first free to a previously full slab - instead of putting the slab on a shared partial list, we can more cheaply freeze it and put it on the per-cpu list. To control how large a percpu partial list can grow for a kmem cache, set_cpu_partial() calculates a target number of free objects on each cpu's percpu partial list, and this can be also set by the sysfs file cpu_partial. However, the tracking of actual number of objects is imprecise, in order to limit overhead from cpu X freeing an objects to a slab on percpu partial list of cpu Y. Basically, the percpu partial slabs form a single linked list, and when we add a new slab to the list with current head "oldpage", we set in the struct page of the slab we're adding: page->pages = oldpage->pages + 1; // this is precise page->pobjects = oldpage->pobjects + (page->objects - page->inuse); page->next = oldpage; Thus the real number of free objects in the slab (objects - inuse) is only determined at the moment of adding the slab to the percpu partial list, and further freeing doesn't update the pobjects counter nor propagate it to the current list head. As Jann reports [1], this can easily lead to large inaccuracies, where the target number of objects (up to 30 by default) can translate to the same number of (empty) slab pages on the list. In case 2) above, we put a slab with 1 free object on the list, thus only increase page->pobjects by 1, even if there are subsequent frees on the same slab. Jann has noticed this in practice and so did we [2] when investigating significant increase of kmemcg usage after switching from SLAB to SLUB. While this is no longer a problem in kmemcg context thanks to the accounting rewrite in 5.9, the memory waste is still not ideal and it's questionable whether it makes sense to perform free object count based control when object counts can easily become so much inaccurate. So this patch converts the accounting to be based on number of pages only (which is precise) and removes the page->pobjects field completely. This is also ultimately simpler. To retain the existing set_cpu_partial() heuristic, first calculate the target number of objects as previously, but then convert it to target number of pages by assuming the pages will be half-filled on average. This assumption might obviously also be inaccurate in practice, but cannot degrade to actual number of pages being equal to the target number of objects. We could also skip the intermediate step with target number of objects and rewrite the heuristic in terms of pages. However we still have the sysfs file cpu_partial which uses number of objects and could break existing users if it suddenly becomes number of pages, so this patch doesn't do that. In practice, after this patch the heuristics limit the size of percpu partial list up to 2 pages. In case of a reported regression (which would mean some workload has benefited from the previous imprecise object based counting), we can tune the heuristics to get a better compromise within the new scheme, while still avoid the unexpectedly long percpu partial lists. [1] https://lore.kernel.org/linux-mm/CAG48ez2Qx5K1Cab-m8BdSibp6wLTip6ro4=-umR7BLsEgjEYzA@mail.gmail.com/ [2] https://lore.kernel.org/all/2f0f46e8-2535-410a-1859-e9cfa4e57c18@suse.cz/ ========== Evaluation ========== Mel was kind enough to run v1 through mmtests machinery for netperf (localhost) and hackbench and, for most significant results see below. So there are some apparent regressions, especially with hackbench, which I think ultimately boils down to having shorter percpu partial lists on average and some benchmarks benefiting from longer ones. Monitoring slab usage also indicated less memory usage by slab. Based on that, the following patch will bump the defaults to allow longer percpu partial lists than after this patch. However the goal is certainly not such that we would limit the percpu partial lists to 30 pages just because previously a specific alloc/free pattern could lead to the limit of 30 objects translate to a limit to 30 pages - that would make little sense. This is a correctness patch, and if a workload benefits from larger lists, the sysfs tuning knobs are still there to allow that. Netperf 2-socket Intel(R) Xeon(R) Gold 5218R CPU @ 2.10GHz (20 cores, 40 threads per socket), 384GB RAM TCP-RR: hmean before 127045.79 after 121092.94 (-4.69%, worse) stddev before 2634.37 after 1254.08 UDP-RR: hmean before 166985.45 after 160668.94 ( -3.78%, worse) stddev before 4059.69 after 1943.63 2-socket Intel(R) Xeon(R) CPU E5-2698 v4 @ 2.20GHz (20 cores, 40 threads per socket), 512GB RAM TCP-RR: hmean before 84173.25 after 76914.72 ( -8.62%, worse) UDP-RR: hmean before 93571.12 after 96428.69 ( 3.05%, better) stddev before 23118.54 after 16828.14 2-socket Intel(R) Xeon(R) CPU E5-2670 v3 @ 2.30GHz (12 cores, 24 threads per socket), 64GB RAM TCP-RR: hmean before 49984.92 after 48922.27 ( -2.13%, worse) stddev before 6248.15 after 4740.51 UDP-RR: hmean before 61854.31 after 68761.81 ( 11.17%, better) stddev before 4093.54 after 5898.91 other machines - within 2% Hackbench (results before and after the patch, negative % means worse) 2-socket AMD EPYC 7713 (64 cores, 128 threads per core), 256GB RAM hackbench-process-sockets Amean 1 0.5380 0.5583 ( -3.78%) Amean 4 0.7510 0.8150 ( -8.52%) Amean 7 0.7930 0.9533 ( -20.22%) Amean 12 0.7853 1.1313 ( -44.06%) Amean 21 1.1520 1.4993 ( -30.15%) Amean 30 1.6223 1.9237 ( -18.57%) Amean 48 2.6767 2.9903 ( -11.72%) Amean 79 4.0257 5.1150 ( -27.06%) Amean 110 5.5193 7.4720 ( -35.38%) Amean 141 7.2207 9.9840 ( -38.27%) Amean 172 8.4770 12.1963 ( -43.88%) Amean 203 9.6473 14.3137 ( -48.37%) Amean 234 11.3960 18.7917 ( -64.90%) Amean 265 13.9627 22.4607 ( -60.86%) Amean 296 14.9163 26.0483 ( -74.63%) hackbench-thread-sockets Amean 1 0.5597 0.5877 ( -5.00%) Amean 4 0.7913 0.8960 ( -13.23%) Amean 7 0.8190 1.0017 ( -22.30%) Amean 12 0.9560 1.1727 ( -22.66%) Amean 21 1.7587 1.5660 ( 10.96%) Amean 30 2.4477 1.9807 ( 19.08%) Amean 48 3.4573 3.0630 ( 11.41%) Amean 79 4.7903 5.1733 ( -8.00%) Amean 110 6.1370 7.4220 ( -20.94%) Amean 141 7.5777 9.2617 ( -22.22%) Amean 172 9.2280 11.0907 ( -20.18%) Amean 203 10.2793 13.3470 ( -29.84%) Amean 234 11.2410 17.1070 ( -52.18%) Amean 265 12.5970 23.3323 ( -85.22%) Amean 296 17.1540 24.2857 ( -41.57%) 2-socket Intel(R) Xeon(R) Gold 5218R CPU @ 2.10GHz (20 cores, 40 threads per socket), 384GB RAM hackbench-process-sockets Amean 1 0.5760 0.4793 ( 16.78%) Amean 4 0.9430 0.9707 ( -2.93%) Amean 7 1.5517 1.8843 ( -21.44%) Amean 12 2.4903 2.7267 ( -9.49%) Amean 21 3.9560 4.2877 ( -8.38%) Amean 30 5.4613 5.8343 ( -6.83%) Amean 48 8.5337 9.2937 ( -8.91%) Amean 79 14.0670 15.2630 ( -8.50%) Amean 110 19.2253 21.2467 ( -10.51%) Amean 141 23.7557 25.8550 ( -8.84%) Amean 172 28.4407 29.7603 ( -4.64%) Amean 203 33.3407 33.9927 ( -1.96%) Amean 234 38.3633 39.1150 ( -1.96%) Amean 265 43.4420 43.8470 ( -0.93%) Amean 296 48.3680 48.9300 ( -1.16%) hackbench-thread-sockets Amean 1 0.6080 0.6493 ( -6.80%) Amean 4 1.0000 1.0513 ( -5.13%) Amean 7 1.6607 2.0260 ( -22.00%) Amean 12 2.7637 2.9273 ( -5.92%) Amean 21 5.0613 4.5153 ( 10.79%) Amean 30 6.3340 6.1140 ( 3.47%) Amean 48 9.0567 9.5577 ( -5.53%) Amean 79 14.5657 15.7983 ( -8.46%) Amean 110 19.6213 21.6333 ( -10.25%) Amean 141 24.1563 26.2697 ( -8.75%) Amean 172 28.9687 30.2187 ( -4.32%) Amean 203 33.9763 34.6970 ( -2.12%) Amean 234 38.8647 39.3207 ( -1.17%) Amean 265 44.0813 44.1507 ( -0.16%) Amean 296 49.2040 49.4330 ( -0.47%) 2-socket Intel(R) Xeon(R) CPU E5-2698 v4 @ 2.20GHz (20 cores, 40 threads per socket), 512GB RAM hackbench-process-sockets Amean 1 0.5027 0.5017 ( 0.20%) Amean 4 1.1053 1.2033 ( -8.87%) Amean 7 1.8760 2.1820 ( -16.31%) Amean 12 2.9053 3.1810 ( -9.49%) Amean 21 4.6777 4.9920 ( -6.72%) Amean 30 6.5180 6.7827 ( -4.06%) Amean 48 10.0710 10.5227 ( -4.48%) Amean 79 16.4250 17.5053 ( -6.58%) Amean 110 22.6203 24.4617 ( -8.14%) Amean 141 28.0967 31.0363 ( -10.46%) Amean 172 34.4030 36.9233 ( -7.33%) Amean 203 40.5933 43.0850 ( -6.14%) Amean 234 46.6477 48.7220 ( -4.45%) Amean 265 53.0530 53.9597 ( -1.71%) Amean 296 59.2760 59.9213 ( -1.09%) hackbench-thread-sockets Amean 1 0.5363 0.5330 ( 0.62%) Amean 4 1.1647 1.2157 ( -4.38%) Amean 7 1.9237 2.2833 ( -18.70%) Amean 12 2.9943 3.3110 ( -10.58%) Amean 21 4.9987 5.1880 ( -3.79%) Amean 30 6.7583 7.0043 ( -3.64%) Amean 48 10.4547 10.8353 ( -3.64%) Amean 79 16.6707 17.6790 ( -6.05%) Amean 110 22.8207 24.4403 ( -7.10%) Amean 141 28.7090 31.0533 ( -8.17%) Amean 172 34.9387 36.8260 ( -5.40%) Amean 203 41.1567 43.0450 ( -4.59%) Amean 234 47.3790 48.5307 ( -2.43%) Amean 265 53.9543 54.6987 ( -1.38%) Amean 296 60.0820 60.2163 ( -0.22%) 1-socket Intel(R) Xeon(R) CPU E3-1240 v5 @ 3.50GHz (4 cores, 8 threads), 32 GB RAM hackbench-process-sockets Amean 1 1.4760 1.5773 ( -6.87%) Amean 3 3.9370 4.0910 ( -3.91%) Amean 5 6.6797 6.9357 ( -3.83%) Amean 7 9.3367 9.7150 ( -4.05%) Amean 12 15.7627 16.1400 ( -2.39%) Amean 18 23.5360 23.6890 ( -0.65%) Amean 24 31.0663 31.3137 ( -0.80%) Amean 30 38.7283 39.0037 ( -0.71%) Amean 32 41.3417 41.6097 ( -0.65%) hackbench-thread-sockets Amean 1 1.5250 1.6043 ( -5.20%) Amean 3 4.0897 4.2603 ( -4.17%) Amean 5 6.7760 7.0933 ( -4.68%) Amean 7 9.4817 9.9157 ( -4.58%) Amean 12 15.9610 16.3937 ( -2.71%) Amean 18 23.9543 24.3417 ( -1.62%) Amean 24 31.4400 31.7217 ( -0.90%) Amean 30 39.2457 39.5467 ( -0.77%) Amean 32 41.8267 42.1230 ( -0.71%) 2-socket Intel(R) Xeon(R) CPU E5-2670 v3 @ 2.30GHz (12 cores, 24 threads per socket), 64GB RAM hackbench-process-sockets Amean 1 1.0347 1.0880 ( -5.15%) Amean 4 1.7267 1.8527 ( -7.30%) Amean 7 2.6707 2.8110 ( -5.25%) Amean 12 4.1617 4.3383 ( -4.25%) Amean 21 7.0070 7.2600 ( -3.61%) Amean 30 9.9187 10.2397 ( -3.24%) Amean 48 15.6710 16.3923 ( -4.60%) Amean 79 24.7743 26.1247 ( -5.45%) Amean 110 34.3000 35.9307 ( -4.75%) Amean 141 44.2043 44.8010 ( -1.35%) Amean 172 54.2430 54.7260 ( -0.89%) Amean 192 60.6557 60.9777 ( -0.53%) hackbench-thread-sockets Amean 1 1.0610 1.1353 ( -7.01%) Amean 4 1.7543 1.9140 ( -9.10%) Amean 7 2.7840 2.9573 ( -6.23%) Amean 12 4.3813 4.4937 ( -2.56%) Amean 21 7.3460 7.5350 ( -2.57%) Amean 30 10.2313 10.5190 ( -2.81%) Amean 48 15.9700 16.5940 ( -3.91%) Amean 79 25.3973 26.6637 ( -4.99%) Amean 110 35.1087 36.4797 ( -3.91%) Amean 141 45.8220 46.3053 ( -1.05%) Amean 172 55.4917 55.7320 ( -0.43%) Amean 192 62.7490 62.5410 ( 0.33%) Link: https://lkml.kernel.org/r/20211012134651.11258-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Jann Horn <jannh@google.com> Cc: Roman Gushchin <guro@fb.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-06slub: add back check for free nonslab objectsKefeng Wang1-1/+3
After commit f227f0faf63b ("slub: fix unreclaimable slab stat for bulk free"), the check for free nonslab page is replaced by VM_BUG_ON_PAGE, which only check with CONFIG_DEBUG_VM enabled, but this config may impact performance, so it only for debug. Commit 0937502af7c9 ("slub: Add check for kfree() of non slab objects.") add the ability, which should be needed in any configs to catch the invalid free, they even could be potential issue, eg, memory corruption, use after free and double free, so replace VM_BUG_ON_PAGE to WARN_ON_ONCE, add object address printing to help use to debug the issue. Link: https://lkml.kernel.org/r/20210930070214.61499-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rienjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-11-02Merge tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linuxLinus Torvalds1-2/+2
Pull printk updates from Petr Mladek: - Extend %pGp print format to print hex value of the page flags - Use kvmalloc instead of kmalloc to allocate devkmsg buffers - Misc cleanup and warning fixes * tag 'printk-for-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: vsprintf: Update %pGp documentation about that it prints hex value lib/vsprintf.c: Amend static asserts for format specifier flags vsprintf: Make %pGp print the hex value test_printf: Append strings more efficiently test_printf: Remove custom appending of '|' test_printf: Remove separate page_flags variable test_printf: Make pft array const ia64: don't do IA64_CMPXCHG_DEBUG without CONFIG_PRINTK printk: use gnu_printf format attribute for printk_sprint() printk: avoid -Wsometimes-uninitialized warning printk: use kvmalloc instead of kmalloc for devkmsg_user
2021-10-27vsprintf: Make %pGp print the hex valueMatthew Wilcox (Oracle)1-2/+2
All existing users of %pGp want the hex value as well as the decoded flag names. This looks awkward (passing the same parameter to printf twice), so move that functionality into the core. If we want, we can make that optional with flag arguments to %pGp in the future. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yafang Shao <laoar.shao@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20211019142621.2810043-6-willy@infradead.org
2021-10-18mm, slub: fix incorrect memcg slab count for bulk freeMiaohe Lin1-1/+3
kmem_cache_free_bulk() will call memcg_slab_free_hook() for all objects when doing bulk free. So we shouldn't call memcg_slab_free_hook() again for bulk free to avoid incorrect memcg slab count. Link: https://lkml.kernel.org/r/20210916123920.48704-6-linmiaohe@huawei.com Fixes: d1b2cf6cb84a ("mm: memcg/slab: uncharge during kmem_cache_free_bulk()") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-18mm, slub: fix potential use-after-free in slab_debugfs_fopsMiaohe Lin1-2/+4
When sysfs_slab_add failed, we shouldn't call debugfs_slab_add() for s because s will be freed soon. And slab_debugfs_fops will use s later leading to a use-after-free. Link: https://lkml.kernel.org/r/20210916123920.48704-5-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-18mm, slub: fix potential memoryleak in kmem_cache_open()Miaohe Lin1-1/+1
In error path, the random_seq of slub cache might be leaked. Fix this by using __kmem_cache_release() to release all the relevant resources. Link: https://lkml.kernel.org/r/20210916123920.48704-4-linmiaohe@huawei.com Fixes: 210e7a43fa90 ("mm: SLUB freelist randomization") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-18mm, slub: fix mismatch between reconstructed freelist depth and cntMiaohe Lin1-2/+9
If object's reuse is delayed, it will be excluded from the reconstructed freelist. But we forgot to adjust the cnt accordingly. So there will be a mismatch between reconstructed freelist depth and cnt. This will lead to free_debug_processing() complaining about freelist count or a incorrect slub inuse count. Link: https://lkml.kernel.org/r/20210916123920.48704-3-linmiaohe@huawei.com Fixes: c3895391df38 ("kasan, slub: fix handling of kasan_slab_free hook") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-10-18mm, slub: fix two bugs in slab_debug_trace_open()Miaohe Lin1-1/+7
Patch series "Fixups for slub". This series contains various bug fixes for slub. We fix memoryleak, use-afer-free, NULL pointer dereferencing and so on in slub. More details can be found in the respective changelogs. This patch (of 5): It's possible that __seq_open_private() will return NULL. So we should check it before using lest dereferencing NULL pointer. And in error paths, we forgot to release private buffer via seq_release_private(). Memory will leak in these paths. Link: https://lkml.kernel.org/r/20210916123920.48704-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20210916123920.48704-2-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Faiyaz Mohammed <faiyazm@codeaurora.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Bharata B Rao <bharata@linux.ibm.com> Cc: Roman Gushchin <guro@fb.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-04mm, slub: convert kmem_cpu_slab protection to local_lockVlastimil Babka1-35/+111
Embed local_lock into struct kmem_cpu_slab and use the irq-safe versions of local_lock instead of plain local_irq_save/restore. On !PREEMPT_RT that's equivalent, with better lockdep visibility. On PREEMPT_RT that means better preemption. However, the cost on PREEMPT_RT is the loss of lockless fast paths which only work with cpu freelist. Those are designed to detect and recover from being preempted by other conflicting operations (both fast or slow path), but the slow path operations assume they cannot be preempted by a fast path operation, which is guaranteed naturally with disabled irqs. With local locks on PREEMPT_RT, the fast paths now also need to take the local lock to avoid races. In the allocation fastpath slab_alloc_node() we can just defer to the slowpath __slab_alloc() which also works with cpu freelist, but under the local lock. In the free fastpath do_slab_free() we have to add a new local lock protected version of freeing to the cpu freelist, as the existing slowpath only works with the page freelist. Also update the comment about locking scheme in SLUB to reflect changes done by this series. [ Mike Galbraith <efault@gmx.de>: use local_lock() without irq in PREEMPT_RT scope; debugging of RT crashes resulting in put_cpu_partial() locking changes ] Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm, slub: use migrate_disable() on PREEMPT_RTVlastimil Babka1-9/+30
We currently use preempt_disable() (directly or via get_cpu_ptr()) to stabilize the pointer to kmem_cache_cpu. On PREEMPT_RT this would be incompatible with the list_lock spinlock. We can use migrate_disable() instead, but that increases overhead on !PREEMPT_RT as it's an unconditional function call. In order to get the best available mechanism on both PREEMPT_RT and !PREEMPT_RT, introduce private slub_get_cpu_ptr() and slub_put_cpu_ptr() wrappers and use them. Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm, slub: protect put_cpu_partial() with disabled irqs instead of cmpxchgVlastimil Babka1-37/+44
Jann Horn reported [1] the following theoretically possible race: task A: put_cpu_partial() calls preempt_disable() task A: oldpage = this_cpu_read(s->cpu_slab->partial) interrupt: kfree() reaches unfreeze_partials() and discards the page task B (on another CPU): reallocates page as page cache task A: reads page->pages and page->pobjects, which are actually halves of the pointer page->lru.prev task B (on another CPU): frees page interrupt: allocates page as SLUB page and places it on the percpu partial list task A: this_cpu_cmpxchg() succeeds which would cause page->pages and page->pobjects to end up containing halves of pointers that would then influence when put_cpu_partial() happens and show up in root-only sysfs files. Maybe that's acceptable, I don't know. But there should probably at least be a comment for now to point out that we're reading union fields of a page that might be in a completely different state. Additionally, the this_cpu_cmpxchg() approach in put_cpu_partial() is only safe against s->cpu_slab->partial manipulation in ___slab_alloc() if the latter disables irqs, otherwise a __slab_free() in an irq handler could call put_cpu_partial() in the middle of ___slab_alloc() manipulating ->partial and corrupt it. This becomes an issue on RT after a local_lock is introduced in later patch. The fix means taking the local_lock also in put_cpu_partial() on RT. After debugging this issue, Mike Galbraith suggested [2] that to avoid different locking schemes on RT and !RT, we can just protect put_cpu_partial() with disabled irqs (to be converted to local_lock_irqsave() later) everywhere. This should be acceptable as it's not a fast path, and moving the actual partial unfreezing outside of the irq disabled section makes it short, and with the retry loop gone the code can be also simplified. In addition, the race reported by Jann should no longer be possible. [1] https://lore.kernel.org/lkml/CAG48ez1mvUuXwg0YPH5ANzhQLpbphqk-ZS+jbRz+H66fvm4FcA@mail.gmail.com/ [2] https://lore.kernel.org/linux-rt-users/e3470ab357b48bccfbd1f5133b982178a7d2befb.camel@gmx.de/ Reported-by: Jann Horn <jannh@google.com> Suggested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm, slub: make slab_lock() disable irqs with PREEMPT_RTVlastimil Babka1-17/+41
We need to disable irqs around slab_lock() (a bit spinlock) to make it irq-safe. Most calls to slab_lock() are nested under spin_lock_irqsave() which doesn't disable irqs on PREEMPT_RT, so add explicit disabling with PREEMPT_RT. The exception is cmpxchg_double_slab() which already disables irqs, so use a __slab_[un]lock() variant without irq disable there. slab_[un]lock() thus needs a flags pointer parameter, which is unused on !RT. free_debug_processing() now has two flags variables, which looks odd, but only one is actually used - the one used in spin_lock_irqsave() on !RT and the one used in slab_lock() on RT. As a result, __cmpxchg_double_slab() and cmpxchg_double_slab() become effectively identical on RT, as both will disable irqs, which is necessary on RT as most callers of this function also rely on irqsaving lock operations. Thus, assert that irqs are already disabled in __cmpxchg_double_slab() only on !RT and also change the VM_BUG_ON assertion to the more standard lockdep_assert one. Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm: slub: make object_map_lock a raw_spinlock_tSebastian Andrzej Siewior1-3/+3
The variable object_map is protected by object_map_lock. The lock is always acquired in debug code and within already atomic context Make object_map_lock a raw_spinlock_t. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ contextSebastian Andrzej Siewior1-16/+78
flush_all() flushes a specific SLAB cache on each CPU (where the cache is present). The deactivate_slab()/__free_slab() invocation happens within IPI handler and is problematic for PREEMPT_RT. The flush operation is not a frequent operation or a hot path. The per-CPU flush operation can be moved to within a workqueue. Because a workqueue handler, unlike IPI handler, does not disable irqs, flush_slab() now has to disable them for working with the kmem_cache_cpu fields. deactivate_slab() is safe to call with irqs enabled. [vbabka@suse.cz: adapt to new SLUB changes] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm, slab: split out the cpu offline variant of flush_slab()Vlastimil Babka1-2/+10
flush_slab() is called either as part IPI handler on given live cpu, or as a cleanup on behalf of another cpu that went offline. The first case needs to protect updating the kmem_cache_cpu fields with disabled irqs. Currently the whole call happens with irqs disabled by the IPI handler, but the following patch will change from IPI to workqueue, and flush_slab() will have to disable irqs (to be replaced with a local lock later) in the critical part. To prepare for this change, replace the call to flush_slab() for the dead cpu handling with an opencoded variant that will not disable irqs nor take a local lock. Suggested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2021-09-04mm, slub: don't disable irqs in slub_cpu_dead()Vlastimil Babka1-5/+1
slub_cpu_dead() cleans up for an offlined cpu from another cpu and calls only functions that are now irq safe, so we don't need to disable irqs anymore. Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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