From: Yu Zhao <yuzhao@google.com>
To: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andi Kleen <ak@linux.intel.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>,
Jesse Barnes <jsbarnes@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@suse.de>,
Michael Larabel <Michael@michaellarabel.com>,
Rik van Riel <riel@surriel.com>, Vlastimil Babka <vbabka@suse.cz>,
Will Deacon <will@kernel.org>, Ying Huang <ying.huang@intel.com>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
page-reclaim@google.com, x86@kernel.org,
Konstantin Kharlamov <Hi-Angel@yandex.ru>
Subject: Re: [PATCH v6 6/9] mm: multigenerational lru: aging
Date: Tue, 11 Jan 2022 16:16:57 -0700 [thread overview]
Message-ID: <Yd4P6bEJI8YlXq0H@google.com> (raw)
In-Reply-To: <YdxKORU9OWCv114O@dhcp22.suse.cz>
On Mon, Jan 10, 2022 at 04:01:13PM +0100, Michal Hocko wrote:
> On Thu 06-01-22 17:12:18, Michal Hocko wrote:
> > On Tue 04-01-22 13:22:25, Yu Zhao wrote:
> > > +static struct lru_gen_mm_walk *alloc_mm_walk(void)
> > > +{
> > > + if (!current->reclaim_state || !current->reclaim_state->mm_walk)
> > > + return kvzalloc(sizeof(struct lru_gen_mm_walk), GFP_KERNEL);
>
> One thing I have overlooked completely.
I appreciate your attention to details but GFP_KERNEL is legit in the
reclaim path. It's been used many years in our production, e.g.,
page reclaim
swap_writepage()
frontswap_store()
zswap_frontswap_store()
zswap_entry_cache_alloc(GFP_KERNEL)
(And I always test my changes with lockdep, kasan, DEBUG_VM, etc., no
warnings ever seen from using GFP_KERNEL in the reclaim path.)
> You cannot really use GFP_KERNEL
> allocation here because the reclaim context can be constrained (e.g.
> GFP_NOFS). This allocation will not do any reclaim as it is PF_MEMALLOC
> but I suspect that the lockdep will complain anyway.
>
> Also kvmalloc is not really great here. a) vmalloc path is never
> executed for small objects and b) we do not really want to make a
> dependency between vmalloc and the reclaim (by vmalloc -> reclaim ->
> vmalloc).
>
> Even if we rule out vmalloc and look at kmalloc alone. Is this really
> safe? I do not see any recursion prevention in the SL.B code. Maybe this
> just happens to work but the dependency should be really documented so
> that future SL.B changes won't break the whole scheme.
Affirmative, as Vlastimil has clarified.
Thanks!
next prev parent reply other threads:[~2022-01-11 23:17 UTC|newest]
Thread overview: 111+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 20:22 [PATCH v6 0/9] Multigenerational LRU Framework Yu Zhao
2022-01-04 20:22 ` [PATCH v6 1/9] mm: x86, arm64: add arch_has_hw_pte_young() Yu Zhao
2022-01-05 10:45 ` Will Deacon
2022-01-05 20:47 ` Yu Zhao
2022-01-06 10:30 ` Will Deacon
2022-01-07 7:25 ` Yu Zhao
2022-01-11 14:19 ` Will Deacon
2022-01-11 22:27 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 2/9] mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG Yu Zhao
2022-01-04 21:24 ` Linus Torvalds
2022-01-04 20:22 ` [PATCH v6 3/9] mm/vmscan.c: refactor shrink_node() Yu Zhao
2022-01-04 20:22 ` [PATCH v6 4/9] mm: multigenerational lru: groundwork Yu Zhao
2022-01-04 21:34 ` Linus Torvalds
2022-01-11 8:16 ` Aneesh Kumar K.V
2022-01-12 2:16 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 5/9] mm: multigenerational lru: mm_struct list Yu Zhao
2022-01-07 9:06 ` Michal Hocko
2022-01-08 0:19 ` Yu Zhao
2022-01-10 15:21 ` Michal Hocko
2022-01-12 8:08 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 6/9] mm: multigenerational lru: aging Yu Zhao
2022-01-06 16:06 ` Michal Hocko
2022-01-06 21:27 ` Yu Zhao
2022-01-07 8:43 ` Michal Hocko
2022-01-07 21:12 ` Yu Zhao
2022-01-06 16:12 ` Michal Hocko
2022-01-06 21:41 ` Yu Zhao
2022-01-07 8:55 ` Michal Hocko
2022-01-07 9:00 ` Michal Hocko
2022-01-10 3:58 ` Yu Zhao
2022-01-10 14:37 ` Michal Hocko
2022-01-13 9:43 ` Yu Zhao
2022-01-13 12:02 ` Michal Hocko
2022-01-19 6:31 ` Yu Zhao
2022-01-19 9:44 ` Michal Hocko
2022-01-10 15:01 ` Michal Hocko
2022-01-10 16:01 ` Vlastimil Babka
2022-01-10 16:25 ` Michal Hocko
2022-01-11 23:16 ` Yu Zhao [this message]
2022-01-12 10:28 ` Michal Hocko
2022-01-13 9:25 ` Yu Zhao
2022-01-07 13:11 ` Michal Hocko
2022-01-07 23:36 ` Yu Zhao
2022-01-10 15:35 ` Michal Hocko
2022-01-11 1:18 ` Yu Zhao
2022-01-11 9:00 ` Michal Hocko
[not found] ` <1641900108.61dd684cb0e59@mail.inbox.lv>
2022-01-11 12:15 ` Michal Hocko
2022-01-13 17:00 ` Alexey Avramov
2022-01-11 14:22 ` Alexey Avramov
2022-01-07 14:44 ` Michal Hocko
2022-01-10 4:47 ` Yu Zhao
2022-01-10 10:54 ` Michal Hocko
2022-01-19 7:04 ` Yu Zhao
2022-01-19 9:42 ` Michal Hocko
2022-01-23 21:28 ` Yu Zhao
2022-01-24 14:01 ` Michal Hocko
2022-01-10 16:57 ` Michal Hocko
2022-01-12 1:01 ` Yu Zhao
2022-01-12 10:17 ` Michal Hocko
2022-01-12 23:43 ` Yu Zhao
2022-01-13 11:57 ` Michal Hocko
2022-01-23 21:40 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 7/9] mm: multigenerational lru: eviction Yu Zhao
2022-01-11 10:37 ` Aneesh Kumar K.V
2022-01-12 8:05 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 8/9] mm: multigenerational lru: user interface Yu Zhao
2022-01-10 10:27 ` Mike Rapoport
2022-01-12 8:35 ` Yu Zhao
2022-01-12 10:31 ` Michal Hocko
2022-01-12 15:45 ` Mike Rapoport
2022-01-13 9:47 ` Yu Zhao
2022-01-13 10:31 ` Aneesh Kumar K.V
2022-01-13 23:02 ` Yu Zhao
2022-01-14 5:20 ` Aneesh Kumar K.V
2022-01-14 6:50 ` Yu Zhao
2022-01-04 20:22 ` [PATCH v6 9/9] mm: multigenerational lru: Kconfig Yu Zhao
2022-01-04 21:39 ` Linus Torvalds
2022-01-04 20:22 ` [PATCH v6 0/9] Multigenerational LRU Framework Yu Zhao
2022-01-04 20:30 ` Yu Zhao
2022-01-04 21:43 ` Linus Torvalds
2022-01-05 21:12 ` Yu Zhao
2022-01-07 9:38 ` Michal Hocko
2022-01-07 18:45 ` Yu Zhao
2022-01-10 15:39 ` Michal Hocko
2022-01-10 22:04 ` Yu Zhao
2022-01-10 22:46 ` Jesse Barnes
2022-01-11 1:41 ` Linus Torvalds
2022-01-11 10:40 ` Michal Hocko
2022-01-11 8:41 ` Yu Zhao
2022-01-11 8:53 ` Holger Hoffstätte
2022-01-11 16:04 ` Shuang Zhai
2022-01-12 1:46 ` Suleiman Souhlal
2022-01-12 6:07 ` Sofia Trinh
2022-01-18 9:21 ` Yu Zhao
2022-01-18 9:36 ` Donald Carr
2022-01-19 20:19 ` Steven Barrett
2022-01-19 22:25 ` Brian Geffon
2022-01-05 2:44 ` Shuang Zhai
2022-01-05 8:55 ` SeongJae Park
2022-01-05 10:53 ` Yu Zhao
2022-01-05 11:12 ` Borislav Petkov
2022-01-05 11:25 ` SeongJae Park
2022-01-05 21:06 ` Yu Zhao
2022-01-10 14:49 ` Alexey Avramov
2022-01-11 10:24 ` Alexey Avramov
2022-01-12 20:56 ` Oleksandr Natalenko
2022-01-13 8:59 ` Yu Zhao
2022-01-23 5:43 ` Barry Song
2022-01-25 6:48 ` Yu Zhao
2022-01-28 8:54 ` Barry Song
2022-02-08 9:16 ` Yu Zhao
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