From: Christopher Lameter <cl@linux.com> To: Yu Zhao <yuzhao@google.com> Cc: Pekka Enberg <penberg@kernel.org>, David Rientjes <rientjes@google.com>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrew Morton <akpm@linux-foundation.org>, "Kirill A . Shutemov" <kirill@shutemov.name>, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>, linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Subject: Re: [PATCH v4 2/2] mm: avoid slub allocation while holding list_lock Date: Mon, 11 Nov 2019 15:47:03 +0000 (UTC) Message-ID: <alpine.DEB.2.21.1911111543420.10669@www.lameter.com> (raw) In-Reply-To: <20191110184721.GA171640@google.com> On Sun, 10 Nov 2019, Yu Zhao wrote: > On Sat, Nov 09, 2019 at 11:16:28PM +0000, Christopher Lameter wrote: > > On Sat, 9 Nov 2019, Yu Zhao wrote: > > > > > > struct page *page, *h; > > > > + unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL); > > > > + > > > > + if (!map) > > > > + return; > > > > > > What would happen if we are trying to allocate from the slab that is > > > being shut down? And shouldn't the allocation be conditional (i.e., > > > only when CONFIG_SLUB_DEBUG=y)? > > > > Kmalloc slabs are never shut down. > > Maybe I'm not thinking straight -- isn't it what caused the deadlock in > the first place? Well if kmalloc allocations become a problem then we have numerous issues all over the kernel to fix. > Kmalloc slabs can be shut down when memcg is on. Kmalloc needs to work even during shutdown of a memcg. Maybe we need to fix memcg to not allocate from the current memcg during shutdown?
next prev parent reply index Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-09-09 6:10 [PATCH] " 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 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 [this message] 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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