From: "Kirill A. Shutemov" <kirill@shutemov.name> To: Yu Zhao <yuzhao@google.com> Cc: Christoph Lameter <cl@linux.com>, Pekka Enberg <penberg@kernel.org>, David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrew Morton <akpm@linux-foundation.org>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/4] mm: clean up validate_slab() Date: Thu, 12 Sep 2019 12:46:23 +0300 Message-ID: <20190912094623.fn6qdefrnnskdai5@box> (raw) In-Reply-To: <20190912023111.219636-2-yuzhao@google.com> On Wed, Sep 11, 2019 at 08:31:09PM -0600, Yu Zhao wrote: > The function doesn't need to return any value, and the check can be > done in one pass. > > There is a behavior change: before the patch, we stop at the first > invalid free object; after the patch, we stop at the first invalid > object, free or in use. This shouldn't matter because the original > behavior isn't intended anyway. > > Signed-off-by: Yu Zhao <yuzhao@google.com> > --- > mm/slub.c | 21 ++++++++------------- > 1 file changed, 8 insertions(+), 13 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 62053ceb4464..7b7e1ee264ef 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -4386,31 +4386,26 @@ static int count_total(struct page *page) > #endif > > #ifdef CONFIG_SLUB_DEBUG > -static int validate_slab(struct kmem_cache *s, struct page *page, > +static void validate_slab(struct kmem_cache *s, struct page *page, > unsigned long *map) > { > void *p; > void *addr = page_address(page); > > - if (!check_slab(s, page) || > - !on_freelist(s, page, NULL)) > - return 0; > + if (!check_slab(s, page) || !on_freelist(s, page, NULL)) > + return; > > /* Now we know that a valid freelist exists */ > bitmap_zero(map, page->objects); > > get_map(s, page, map); > for_each_object(p, s, addr, page->objects) { > - if (test_bit(slab_index(p, s, addr), map)) > - if (!check_object(s, page, p, SLUB_RED_INACTIVE)) > - return 0; > - } > + u8 val = test_bit(slab_index(p, s, addr), map) ? > + SLUB_RED_INACTIVE : SLUB_RED_ACTIVE; Proper 'if' would be more readable. Other than that look fine to me. > > - for_each_object(p, s, addr, page->objects) > - if (!test_bit(slab_index(p, s, addr), map)) > - if (!check_object(s, page, p, SLUB_RED_ACTIVE)) > - return 0; > - return 1; > + if (!check_object(s, page, p, val)) > + break; > + } > } > > static void validate_slab_slab(struct kmem_cache *s, struct page *page, > -- > 2.23.0.162.g0b9fbb3734-goog > -- Kirill A. Shutemov
next prev parent reply index Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-09 6:10 [PATCH] mm: avoid slub allocation while holding list_lock Yu Zhao 2019-09-09 16:00 ` Kirill A. Shutemov [not found] ` <e5e25aa3-651d-92b4-ac82-c5011c66a7cb@I-love.SAKURA.ne.jp> 2019-09-09 21:39 ` Yu Zhao [not found] ` <201909100141.x8A1fVdu048305@www262.sakura.ne.jp> 2019-09-10 2:16 ` Yu Zhao 2019-09-10 9:16 ` Kirill A. Shutemov 2019-09-11 14:13 ` Andrew Morton 2019-09-12 0:29 ` [PATCH 1/3] mm: correct mask size for slub page->objects Yu Zhao 2019-09-12 0:29 ` [PATCH 2/3] mm: avoid slub allocation while holding list_lock Yu Zhao 2019-09-12 0:44 ` Kirill A. Shutemov 2019-09-12 1:31 ` Yu Zhao 2019-09-12 2:31 ` [PATCH v2 1/4] mm: correct mask size for slub page->objects Yu Zhao 2019-09-12 2:31 ` [PATCH v2 2/4] mm: clean up validate_slab() Yu Zhao 2019-09-12 9:46 ` Kirill A. Shutemov [this message] 2019-09-12 2:31 ` [PATCH v2 3/4] mm: avoid slub allocation while holding list_lock Yu Zhao 2019-09-12 10:04 ` Kirill A. Shutemov 2019-09-12 2:31 ` [PATCH v2 4/4] mm: lock slub page when listing objects Yu Zhao 2019-09-12 10:06 ` Kirill A. Shutemov 2019-09-12 21:12 ` Yu Zhao 2019-09-13 14:58 ` Christopher Lameter 2019-09-12 9:40 ` [PATCH v2 1/4] mm: correct mask size for slub page->objects Kirill A. Shutemov 2019-09-12 21:11 ` Yu Zhao 2019-09-12 22:03 ` Kirill A. Shutemov 2019-09-14 0:07 ` [PATCH v3 1/2] mm: clean up validate_slab() Yu Zhao 2019-09-14 0:07 ` [PATCH v3 2/2] mm: avoid slub allocation while holding list_lock Yu Zhao 2019-09-16 8:39 ` [PATCH v3 1/2] mm: clean up validate_slab() Kirill A. Shutemov 2019-11-08 19:39 ` [PATCH v4 " Yu Zhao 2019-11-08 19:39 ` [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock Yu Zhao 2019-11-09 20:52 ` Christopher Lameter 2019-11-09 23:01 ` Yu Zhao 2019-11-09 23:16 ` Christopher Lameter 2019-11-10 18:47 ` Yu Zhao 2019-11-11 15:47 ` Christopher Lameter 2019-11-11 15:55 ` [FIX] slub: Remove kmalloc under list_lock from list_slab_objects() V2 Christopher Lameter 2019-11-30 23:09 ` Andrew Morton 2019-12-02 15:12 ` Christopher Lameter 2019-12-07 22:03 ` Yu Zhao 2020-01-10 14:11 ` Vlastimil Babka [not found] ` <e0ed44ae-8dae-e8db-9d14-2b09b239af8e@i-love.sakura.ne.jp> 2020-01-13 1:34 ` Christopher Lameter 2019-11-11 18:15 ` [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock Shakeel Butt 2019-09-12 0:29 ` [PATCH 3/3] mm: lock slub page when listing objects Yu Zhao
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