Linux-mm Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
	"Daniel Vetter" <daniel.vetter@ffwll.ch>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org,
	"DRI Development" <dri-devel@lists.freedesktop.org>,
	"Intel Graphics Development" <intel-gfx@lists.freedesktop.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"David Rientjes" <rientjes@google.com>,
	"Christian König" <christian.koenig@amd.com>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Masahiro Yamada" <yamada.masahiro@socionext.com>,
	"Wei Wang" <wvw@google.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Jann Horn" <jannh@google.com>, "Feng Tang" <feng.tang@intel.com>,
	"Kees Cook" <keescook@chromium.org>,
	"Randy Dunlap" <rdunlap@infradead.org>,
	"Daniel Vetter" <daniel.vetter@intel.com>
Subject: Re: [PATCH 2/5] kernel.h: Add non_block_start/end()
Date: Thu, 15 Aug 2019 10:04:15 -0300
Message-ID: <20190815130415.GD21596@ziepe.ca> (raw)
In-Reply-To: <20190815084429.GE9477@dhcp22.suse.cz>

On Thu, Aug 15, 2019 at 10:44:29AM +0200, Michal Hocko wrote:

> As the oom reaper is the primary guarantee of the oom handling forward
> progress it cannot be blocked on anything that might depend on blockable
> memory allocations. These are not really easy to track because they
> might be indirect - e.g. notifier blocks on a lock which other context
> holds while allocating memory or waiting for a flusher that needs memory
> to perform its work.

But lockdep *does* track all this and fs_reclaim_acquire() was created
to solve exactly this problem.

fs_reclaim is a lock and it flows through all the usual lockdep
schemes like any other lock. Any time the page allocator wants to do
something the would deadlock with reclaim it takes the lock.

Failure is expressed by a deadlock cycle in the lockdep map, and
lockdep can handle arbitary complexity through layers of locks, work
queues, threads, etc.

What is missing?

Jason


  reply index

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-14 20:20 [PATCH 0/5] hmm & mmu_notifier debug/lockdep annotations Daniel Vetter
2019-08-14 20:20 ` [PATCH 1/5] mm: Check if mmu notifier callbacks are allowed to fail Daniel Vetter
2019-08-14 22:14   ` Andrew Morton
2019-08-14 23:22     ` Jason Gunthorpe
2019-08-14 23:34     ` Ralph Campbell
2019-08-16 17:19   ` Jason Gunthorpe
2019-08-14 20:20 ` [PATCH 2/5] kernel.h: Add non_block_start/end() Daniel Vetter
2019-08-14 20:45   ` Andrew Morton
2019-08-15  6:52     ` Daniel Vetter
2019-08-15  8:44     ` Michal Hocko
2019-08-15 13:04       ` Jason Gunthorpe [this message]
2019-08-15 13:12         ` Daniel Vetter
2019-08-15 14:37           ` Jason Gunthorpe
2019-08-15 14:43             ` Daniel Vetter
2019-08-15 15:10               ` Jason Gunthorpe
2019-08-15 16:25                 ` Daniel Vetter
2019-08-15 17:35                   ` Jason Gunthorpe
2019-08-15 17:39                     ` Jerome Glisse
2019-08-15 18:01                       ` Jason Gunthorpe
2019-08-15 18:27                         ` Jerome Glisse
2019-08-15 18:57                           ` Jason Gunthorpe
2019-08-15 16:32                 ` Jerome Glisse
2019-08-15 17:16                   ` Jason Gunthorpe
2019-08-15 17:21                     ` Daniel Vetter
2019-08-15 17:35                       ` Jerome Glisse
2019-08-15 13:24         ` Michal Hocko
2019-08-15 22:15       ` Andrew Morton
2019-08-16  8:24         ` Michal Hocko
2019-08-14 23:58   ` Jason Gunthorpe
2019-08-15  6:58     ` Daniel Vetter
2019-08-15 12:23       ` Jason Gunthorpe
2019-08-15 13:21         ` Michal Hocko
2019-08-15 14:12           ` Jason Gunthorpe
2019-08-15 16:00             ` Michal Hocko
2019-08-15 16:56               ` Jason Gunthorpe
2019-08-15 17:11                 ` Jerome Glisse
2019-08-15 17:17                   ` Jason Gunthorpe
2019-08-15 17:42                 ` Michal Hocko
2019-08-15 17:57                   ` Jerome Glisse
2019-08-15 18:24                   ` Jason Gunthorpe
2019-08-15 19:05                     ` Michal Hocko
2019-08-15 19:18                       ` Jason Gunthorpe
2019-08-15 19:35                         ` Michal Hocko
2019-08-15 20:13                           ` Jason Gunthorpe
2019-08-16  8:10                             ` Michal Hocko
2019-08-16 12:19                               ` Jason Gunthorpe
2019-08-16 12:26                                 ` Michal Hocko
2019-08-15 20:16                           ` [Intel-gfx] " Daniel Vetter
2019-08-15 20:27                             ` Jason Gunthorpe
2019-08-15 20:49                               ` Daniel Vetter
2019-08-16  1:00                                 ` Jason Gunthorpe
2019-08-16  6:20                                   ` Daniel Vetter
2019-08-16 12:12                                     ` Jason Gunthorpe
2019-08-16 14:11                                       ` Daniel Vetter
2019-08-16 14:38                                         ` Jason Gunthorpe
2019-08-16 16:36                                           ` Daniel Vetter
2019-08-16 16:54                                             ` Jason Gunthorpe
2019-08-16  8:27                             ` Michal Hocko
2019-08-14 20:20 ` [PATCH 3/5] mm, notifier: Catch sleeping/blocking for !blockable Daniel Vetter
2019-08-15  0:00   ` Jason Gunthorpe
2019-08-15  7:02     ` Daniel Vetter
     [not found]       ` <20190815123556.GB21596@ziepe.ca>
2019-08-17 16:09         ` Daniel Vetter
2019-08-14 20:20 ` [PATCH 4/5] mm, notifier: Add a lockdep map for invalidate_range_start Daniel Vetter
2019-08-15  0:09   ` Jason Gunthorpe
2019-08-15  7:10     ` Daniel Vetter
2019-08-15 12:53       ` Jason Gunthorpe
2019-08-14 20:20 ` [PATCH 5/5] mm/hmm: WARN on illegal ->sync_cpu_device_pagetables errors Daniel Vetter
2019-08-15  0:11   ` Jason Gunthorpe
2019-08-15  7:14     ` Daniel Vetter

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190815130415.GD21596@ziepe.ca \
    --to=jgg@ziepe.ca \
    --cc=akpm@linux-foundation.org \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=christian.koenig@amd.com \
    --cc=daniel.vetter@ffwll.ch \
    --cc=daniel.vetter@intel.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=feng.tang@intel.com \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=jannh@google.com \
    --cc=jglisse@redhat.com \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=rdunlap@infradead.org \
    --cc=rientjes@google.com \
    --cc=tglx@linutronix.de \
    --cc=wvw@google.com \
    --cc=yamada.masahiro@socionext.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org linux-mm@archiver.kernel.org
	public-inbox-index linux-mm


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/ public-inbox