From: Michal Hocko <mhocko@suse.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>, Roman Gushchin <guro@fb.com>,
Wang Hai <wanghai38@huawei.com>,
Muchun Song <songmuchun@bytedance.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] slub: fix unreclaimable slab stat for bulk free
Date: Wed, 28 Jul 2021 18:45:48 +0200 [thread overview]
Message-ID: <YQGJvF8NffbCKT2x@dhcp22.suse.cz> (raw)
In-Reply-To: <20210728155354.3440560-1-shakeelb@google.com>
On Wed 28-07-21 08:53:54, Shakeel Butt wrote:
> SLUB uses page allocator for higher order allocations and update
> unreclaimable slab stat for such allocations. At the moment, the bulk
> free for SLUB does not share code with normal free code path for these
> type of allocations and have missed the stat update. So, fix the stat
> update by common code. The user visible impact of the bug is the
> potential of inconsistent unreclaimable slab stat visible through
> meminfo and vmstat.
>
> Fixes: 6a486c0ad4dc ("mm, sl[ou]b: improve memory accounting")
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
LGTM
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> mm/slub.c | 22 ++++++++++++----------
> 1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 6dad2b6fda6f..03770291aa6b 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3238,6 +3238,16 @@ struct detached_freelist {
> struct kmem_cache *s;
> };
>
> +static inline void free_nonslab_page(struct page *page)
> +{
> + unsigned int order = compound_order(page);
> +
> + VM_BUG_ON_PAGE(!PageCompound(page), page);
> + kfree_hook(page_address(page));
> + mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order));
> + __free_pages(page, order);
> +}
> +
> /*
> * This function progressively scans the array with free objects (with
> * a limited look ahead) and extract objects belonging to the same
> @@ -3274,9 +3284,7 @@ int build_detached_freelist(struct kmem_cache *s, size_t size,
> if (!s) {
> /* Handle kalloc'ed objects */
> if (unlikely(!PageSlab(page))) {
> - BUG_ON(!PageCompound(page));
> - kfree_hook(object);
> - __free_pages(page, compound_order(page));
> + free_nonslab_page(page);
> p[size] = NULL; /* mark object processed */
> return size;
> }
> @@ -4252,13 +4260,7 @@ void kfree(const void *x)
>
> page = virt_to_head_page(x);
> if (unlikely(!PageSlab(page))) {
> - unsigned int order = compound_order(page);
> -
> - BUG_ON(!PageCompound(page));
> - kfree_hook(object);
> - mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
> - -(PAGE_SIZE << order));
> - __free_pages(page, order);
> + free_nonslab_page(page);
> return;
> }
> slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
> --
> 2.32.0.432.gabb21c7263-goog
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-07-28 16:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 15:53 [PATCH] slub: fix unreclaimable slab stat for bulk free Shakeel Butt
2021-07-28 16:45 ` Michal Hocko [this message]
2021-07-28 23:30 ` Roman Gushchin
2021-07-29 5:40 ` Muchun Song
2021-07-29 6:52 ` Kefeng Wang
2021-07-29 14:03 ` Shakeel Butt
2021-08-03 14:24 ` Kefeng Wang
2021-08-03 14:29 ` Vlastimil Babka
2021-08-03 14:44 ` Kefeng Wang
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