From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + mm-slub-implement-slub-version-of-obj_to_index.patch added to -mm tree Date: Wed, 24 Jun 2020 14:46:59 -0700 Message-ID: <20200624214659.GbeCU%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:40418 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731881AbgFXVrA (ORCPT ); Wed, 24 Jun 2020 17:47:00 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org, vbabka@suse.cz, tj@kernel.org, shakeelb@google.com, mhocko@kernel.org, hannes@cmpxchg.org, cl@linux.com, guro@fb.com The patch titled Subject: mm: slub: implement SLUB version of obj_to_index() has been added to the -mm tree. Its filename is mm-slub-implement-slub-version-of-obj_to_index.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-slub-implement-slub-version-of-obj_to_index.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-slub-implement-slub-version-of-obj_to_index.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Roman Gushchin Subject: mm: slub: implement SLUB version of obj_to_index() This commit implements SLUB version of the obj_to_index() function, which will be required to calculate the offset of obj_cgroup in the obj_cgroups vector to store/obtain the objcg ownership data. To make it faster, let's repeat the SLAB's trick introduced by commit 6a2d7a955d8d ("SLAB: use a multiply instead of a divide in obj_to_index()") and avoid an expensive division. Vlastimil Babka noticed, that SLUB does have already a similar function called slab_index(), which is defined only if SLUB_DEBUG is enabled. The function does a similar math, but with a division, and it also takes a page address instead of a page pointer. Let's remove slab_index() and replace it with the new helper __obj_to_index(), which takes a page address. obj_to_index() will be a simple wrapper taking a page pointer and passing page_address(page) into __obj_to_index(). Link: http://lkml.kernel.org/r/20200623174037.3951353-5-guro@fb.com Signed-off-by: Roman Gushchin Reviewed-by: Vlastimil Babka Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Cc: Christoph Lameter Cc: Michal Hocko Cc: Tejun Heo Signed-off-by: Andrew Morton --- include/linux/slub_def.h | 16 ++++++++++++++++ mm/slub.c | 15 +++++---------- 2 files changed, 21 insertions(+), 10 deletions(-) --- a/include/linux/slub_def.h~mm-slub-implement-slub-version-of-obj_to_index +++ a/include/linux/slub_def.h @@ -8,6 +8,7 @@ * (C) 2007 SGI, Christoph Lameter */ #include +#include enum stat_item { ALLOC_FASTPATH, /* Allocation from cpu slab */ @@ -86,6 +87,7 @@ struct kmem_cache { unsigned long min_partial; unsigned int size; /* The size of an object including metadata */ unsigned int object_size;/* The size of an object without metadata */ + struct reciprocal_value reciprocal_size; unsigned int offset; /* Free pointer offset */ #ifdef CONFIG_SLUB_CPU_PARTIAL /* Number of per cpu partial objects to keep around */ @@ -182,4 +184,18 @@ static inline void *nearest_obj(struct k return result; } +/* Determine object index from a given position */ +static inline unsigned int __obj_to_index(const struct kmem_cache *cache, + void *addr, void *obj) +{ + return reciprocal_divide(kasan_reset_tag(obj) - addr, + cache->reciprocal_size); +} + +static inline unsigned int obj_to_index(const struct kmem_cache *cache, + const struct page *page, void *obj) +{ + return __obj_to_index(cache, page_address(page), obj); +} + #endif /* _LINUX_SLUB_DEF_H */ --- a/mm/slub.c~mm-slub-implement-slub-version-of-obj_to_index +++ a/mm/slub.c @@ -317,12 +317,6 @@ static inline void set_freepointer(struc __p < (__addr) + (__objects) * (__s)->size; \ __p += (__s)->size) -/* Determine object index from a given position */ -static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr) -{ - return (kasan_reset_tag(p) - addr) / s->size; -} - static inline unsigned int order_objects(unsigned int order, unsigned int size) { return ((unsigned int)PAGE_SIZE << order) / size; @@ -465,7 +459,7 @@ static unsigned long *get_map(struct kme bitmap_zero(object_map, page->objects); for (p = page->freelist; p; p = get_freepointer(s, p)) - set_bit(slab_index(p, s, addr), object_map); + set_bit(__obj_to_index(s, addr, p), object_map); return object_map; } @@ -3758,6 +3752,7 @@ static int calculate_sizes(struct kmem_c */ size = ALIGN(size, s->align); s->size = size; + s->reciprocal_size = reciprocal_value(size); if (forced_order >= 0) order = forced_order; else @@ -3862,7 +3857,7 @@ static void list_slab_objects(struct kme map = get_map(s, page); for_each_object(p, s, addr, page->objects) { - if (!test_bit(slab_index(p, s, addr), map)) { + if (!test_bit(__obj_to_index(s, addr, p), map)) { pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr); print_tracking(s, p); } @@ -4578,7 +4573,7 @@ static void validate_slab(struct kmem_ca /* Now we know that a valid freelist exists */ map = get_map(s, page); for_each_object(p, s, addr, page->objects) { - u8 val = test_bit(slab_index(p, s, addr), map) ? + u8 val = test_bit(__obj_to_index(s, addr, p), map) ? SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; if (!check_object(s, page, p, val)) @@ -4769,7 +4764,7 @@ static void process_slab(struct loc_trac map = get_map(s, page); for_each_object(p, s, addr, page->objects) - if (!test_bit(slab_index(p, s, addr), map)) + if (!test_bit(__obj_to_index(s, addr, p), map)) add_location(t, s, get_track(s, p, alloc)); put_map(map); } _ Patches currently in -mm which might be from guro@fb.com are mm-memcg-factor-out-memcg-and-lruvec-level-changes-out-of-__mod_lruvec_state.patch mm-memcg-prepare-for-byte-sized-vmstat-items.patch mm-memcg-convert-vmstat-slab-counters-to-bytes.patch mm-slub-implement-slub-version-of-obj_to_index.patch mm-memcg-slab-obj_cgroup-api.patch mm-memcg-slab-allocate-obj_cgroups-for-non-root-slab-pages.patch mm-memcg-slab-save-obj_cgroup-for-non-root-slab-objects.patch mm-memcg-slab-charge-individual-slab-objects-instead-of-pages.patch mm-memcg-slab-deprecate-memorykmemslabinfo.patch mm-memcg-slab-move-memcg_kmem_bypass-to-memcontrolh.patch mm-memcg-slab-use-a-single-set-of-kmem_caches-for-all-accounted-allocations.patch mm-memcg-slab-simplify-memcg-cache-creation.patch mm-memcg-slab-remove-memcg_kmem_get_cache.patch mm-memcg-slab-deprecate-slab_root_caches.patch mm-memcg-slab-remove-redundant-check-in-memcg_accumulate_slabinfo.patch mm-memcg-slab-use-a-single-set-of-kmem_caches-for-all-allocations.patch kselftests-cgroup-add-kernel-memory-accounting-tests.patch tools-cgroup-add-memcg_slabinfopy-tool.patch percpu-return-number-of-released-bytes-from-pcpu_free_area.patch mm-memcg-percpu-account-percpu-memory-to-memory-cgroups.patch mm-memcg-percpu-per-memcg-percpu-memory-statistics.patch mm-memcg-percpu-per-memcg-percpu-memory-statistics-v3.patch mm-memcg-charge-memcg-percpu-memory-to-the-parent-cgroup.patch kselftests-cgroup-add-perpcu-memory-accounting-test.patch