From: Alexander Viro <viro@math.psu.edu>
To: Manfred Spraul <manfreds@colorfullife.com>
Cc: Andrea Arcangeli <andrea@suse.de>,
linux-kernel@vger.rutgers.edu,
Ingo Molnar <mingo@chiara.csoma.elte.hu>,
linux-mm@kvack.org
Subject: Re: locking question: do_mmap(), do_munmap()
Date: Sun, 10 Oct 1999 13:25:14 -0400 (EDT) [thread overview]
Message-ID: <Pine.GSO.4.10.9910101301050.16317-100000@weyl.math.psu.edu> (raw)
In-Reply-To: <3800C2BF.716C9D65@colorfullife.com>
[Apologies to Andrea - idiot me looked into the wrong place ;-<]
On Sun, 10 Oct 1999, Manfred Spraul wrote:
> AFAIK the problem is OOM:
> * a process accesses a not-present, ie page fault:
> ...
> handle_mm_fault(): this process own mm->mmap_sem.
> ->handle_pte_fault().
> -> (eg.) do_wp_page().
> -> get_free_page().
> now get_free_page() notices that there is no free memory.
> --> wakeup kswapd.
>
> * the swapper runs, and it tries to swap out data from that process.
> mm->mmap_sem is already acquired --> lock-up.
Nasty... But adding a big lock around all traversals of the mm->mmap will
hurt like hell. Let's see... The problem is in swap_out_mm(), right? And
it looks for the first suitable page. OK, it looks like we can get a
deadlock only if we call try_to_free_pages() with ->mmap_sem grabbed and
__GFP_WAIT in flags. Umhm... Called only from __get_free_pages() which
sets PF_MEMALLOC... OK, I'll try to look at it.
--
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next prev parent reply other threads:[~1999-10-10 17:25 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.10.9910101713010.364-100000@alpha.random>
1999-10-10 15:52 ` Manfred Spraul
1999-10-10 16:07 ` Alexander Viro
1999-10-10 16:25 ` Alexander Viro
1999-10-10 16:45 ` Manfred Spraul
1999-10-10 17:25 ` Alexander Viro [this message]
1999-10-10 17:12 ` Andrea Arcangeli
1999-10-10 17:48 ` Alexander Viro
1999-10-10 18:42 ` Manfred Spraul
1999-10-10 19:03 ` Alexander Viro
1999-10-10 21:31 ` Manfred Spraul
1999-10-10 21:53 ` Andrea Arcangeli
1999-10-10 22:34 ` Alexander Viro
1999-10-10 23:28 ` Andrea Arcangeli
1999-10-11 15:50 ` Stephen C. Tweedie
1999-10-11 16:05 ` Alexander Viro
1999-10-11 18:02 ` Manfred Spraul
1999-10-11 19:07 ` Kanoj Sarcar
1999-10-11 22:23 ` Stephen C. Tweedie
1999-10-13 1:25 ` Kanoj Sarcar
1999-10-13 7:32 ` Manfred Spraul
1999-10-15 9:58 ` Ralf Baechle
1999-10-15 17:50 ` Kanoj Sarcar
1999-10-13 10:45 ` Stephen C. Tweedie
1999-10-11 20:15 ` Stephen C. Tweedie
1999-10-11 21:14 ` Manfred Spraul
1999-10-11 21:37 ` Alexander Viro
1999-10-11 22:13 ` Manfred Spraul
1999-10-11 22:22 ` Stephen C. Tweedie
1999-10-11 23:01 ` Alexander Viro
1999-10-12 14:06 ` [more fun] " Alexander Viro
1999-10-13 7:35 ` Manfred Spraul
1999-10-13 18:34 ` Kanoj Sarcar
1999-10-13 10:16 ` Stephen C. Tweedie
1999-10-11 20:13 ` Stephen C. Tweedie
1999-10-11 21:40 ` Alexander Viro
1999-10-11 22:20 ` Stephen C. Tweedie
1999-10-11 22:31 ` Alexander Viro
1999-10-13 10:25 ` Stephen C. Tweedie
1999-10-11 15:47 ` Stephen C. Tweedie
1999-10-11 15:43 ` Stephen C. Tweedie
1999-10-10 16:56 ` Andrea Arcangeli
1999-10-11 15:41 ` Stephen C. Tweedie
1999-10-11 15:52 ` Alexander Viro
1999-10-09 12:48 Manfred Spraul
1999-10-09 13:12 ` Alexander Viro
1999-10-09 13:17 ` Manfred Spraul
1999-10-09 13:38 ` Alexander Viro
1999-10-09 16:01 ` Andrea Arcangeli
1999-10-10 13:05 ` Manfred Spraul
1999-10-11 15:09 ` Stephen C. Tweedie
1999-10-11 15:05 ` Stephen C. Tweedie
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