From: Michal Hocko <mhocko@suse.com>
To: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, hch@lst.de, hannes@cmpxchg.org,
akpm@linux-foundation.org, linux-clk@vger.kernel.org,
linux-tegra@vger.kernel.org, linux-input@vger.kernel.org,
rostedt@goodmis.org
Subject: Re: [PATCH v2 8/8] mm: Centralize & improve oom reporting in show_mem.c
Date: Mon, 25 Apr 2022 11:28:26 +0200 [thread overview]
Message-ID: <YmZpuikkgWeF2RPt@dhcp22.suse.cz> (raw)
In-Reply-To: <20220423004607.q4lbz2mplkhlbyhm@moria.home.lan>
On Fri 22-04-22 20:46:07, Kent Overstreet wrote:
> On Fri, Apr 22, 2022 at 05:27:41PM -0700, Roman Gushchin wrote:
[...]
> > > In my experience, it's rare to be _so_ out of memory that small kmalloc
> > > allocations are failing - we'll be triggering the show_mem() report before that
> > > happens.
> >
> > I agree. However the OOM killer _has_ to make the progress even in such rare
> > circumstances.
Absolutely agreed!
> Oh, and the concern is allocator recursion? Yeah, that's a good point.
No, not really. The oom killer is running with PF_MEMALLOC context so no
reclaim recursion is allowed. As I've already pointed out in other
reply the context will have access to memory reserves without any
constrains so it could deplete them completely resulting in other issues
during the recovery.
> Do you know if using memalloc_noreclaim_(save|restore) is sufficient for that,
> or do we want GFP_ATOMIC? I'm already using GFP_ATOMIC for allocations when we
> generate the report on slabs, since we're taking the slab mutex there.
No it's not. You simply _cannot_ allocate from the oom context.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2022-04-25 9:29 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 23:48 [PATCH 0/4] Printbufs & shrinker OOM reporting Kent Overstreet
2022-04-21 23:48 ` [PATCH 1/4] lib/printbuf: New data structure for heap-allocated strings Kent Overstreet
2022-04-21 23:48 ` [PATCH 2/4] mm: Add a .to_text() method for shrinkers Kent Overstreet
2022-04-22 12:21 ` Michal Hocko
2022-04-21 23:48 ` [PATCH 3/4] mm: Centralize & improve oom reporting in show_mem.c Kent Overstreet
2022-04-21 23:48 ` [PATCH 4/4] bcachefs: shrinker.to_text() methods Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 0/8] Printbufs & improved shrinker debugging Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 1/8] lib/printbuf: New data structure for heap-allocated strings Kent Overstreet
2022-04-22 4:20 ` Christoph Hellwig
2022-04-22 5:14 ` Kent Overstreet
2022-04-22 5:22 ` Christoph Hellwig
2022-04-22 5:40 ` Kent Overstreet
2022-04-22 5:52 ` Christoph Hellwig
2022-04-22 6:06 ` Kent Overstreet
2022-04-22 6:11 ` Christoph Hellwig
2022-04-22 6:18 ` Kent Overstreet
2022-04-22 15:37 ` Steven Rostedt
2022-04-22 19:30 ` Kent Overstreet
2022-04-22 19:39 ` Steven Rostedt
2022-04-22 20:30 ` Kent Overstreet
2022-04-22 20:47 ` Steven Rostedt
2022-04-22 21:51 ` Kent Overstreet
2022-04-22 22:20 ` Steven Rostedt
2022-04-22 20:03 ` James Bottomley
2022-04-22 21:13 ` Kent Overstreet
2022-04-23 14:16 ` Rust and Kernel Vendoring [Was Re: [PATCH v2 1/8] lib/printbuf: New data structure for heap-allocated strings] James Bottomley
2022-04-24 20:36 ` Kent Overstreet
2022-04-26 2:22 ` James Bottomley
2022-04-24 23:46 ` [PATCH v2 1/8] lib/printbuf: New data structure for heap-allocated strings Joe Perches
2022-04-25 0:45 ` Kent Overstreet
2022-04-25 2:44 ` Matthew Wilcox
2022-04-25 4:19 ` Kent Overstreet
2022-04-25 4:48 ` Joe Perches
2022-04-25 4:59 ` Kent Overstreet
2022-04-25 5:00 ` Joe Perches
2022-04-25 5:56 ` Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 2/8] Input/joystick/analog: Convert from seq_buf -> printbuf Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 3/8] mm/memcontrol.c: Convert to printbuf Kent Overstreet
2022-04-22 12:28 ` Michal Hocko
2022-04-21 23:48 ` [PATCH v2 4/8] clk: tegra: bpmp: " Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 5/8] mm: Add a .to_text() method for shrinkers Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 6/8] mm: Count requests to free & nr freed per shrinker Kent Overstreet
2022-04-21 23:48 ` [PATCH v2 7/8] mm: Move lib/show_mem.c to mm/ Kent Overstreet
2022-04-22 12:32 ` Michal Hocko
2022-04-21 23:48 ` [PATCH v2 8/8] mm: Centralize & improve oom reporting in show_mem.c Kent Overstreet
2022-04-22 12:58 ` Michal Hocko
2022-04-22 15:09 ` Roman Gushchin
2022-04-22 23:48 ` Kent Overstreet
2022-04-23 0:27 ` Roman Gushchin
2022-04-23 0:46 ` Kent Overstreet
2022-04-23 1:25 ` Roman Gushchin
2022-04-23 11:48 ` Tetsuo Handa
2022-04-25 9:28 ` Michal Hocko [this message]
2022-04-25 15:28 ` Kent Overstreet
2022-04-26 7:17 ` Michal Hocko
2022-04-26 7:26 ` Kent Overstreet
2022-04-26 7:40 ` Michal Hocko
2022-04-30 4:00 ` [PATCH 0/4] Printbufs & shrinker OOM reporting Dave Young
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