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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Yu Zhao <yuzhao@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
	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>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: avoid slub allocation while holding list_lock
Date: Tue, 10 Sep 2019 10:41:31 +0900	[thread overview]
Message-ID: <201909100141.x8A1fVdu048305@www262.sakura.ne.jp> (raw)
In-Reply-To: <20190909213938.GA53078@google.com>

Yu Zhao wrote:
> I think we can safely assume PAGE_SIZE is unsigned long aligned and
> page->objects is non-zero. But if you don't feel comfortable with these
> assumptions, I'd be happy to ensure them explicitly.

I know PAGE_SIZE is unsigned long aligned. If someone by chance happens to
change from "dynamic allocation" to "on stack", get_order() will no longer
be called and the bug will show up.

I don't know whether __get_free_page(GFP_ATOMIC) can temporarily consume more
than 4096 bytes, but if it can, we might want to avoid "dynamic allocation".

By the way, if "struct kmem_cache_node" is object which won't have many thousands
of instances, can't we embed that buffer into "struct kmem_cache_node" because
max size of that buffer is only 4096 bytes?

  reply	other threads:[~2019-09-10  1:41 UTC|newest]

Thread overview: 44+ 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
2019-09-09 20:57   ` Tetsuo Handa
2019-09-09 21:39     ` Yu Zhao
2019-09-10  1:41       ` Tetsuo Handa [this message]
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
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
2019-12-01  1:17                               ` Tetsuo Handa
2019-12-02 15:12                               ` Christopher Lameter
2019-12-07 22:03                                 ` Yu Zhao
2020-01-10 14:11                                   ` Vlastimil Babka
2020-01-12 11:03                                     ` Tetsuo Handa
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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