From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Miller <davem@davemloft.net>,
akpm@linux-foundation.org, linux-mm@kvack.org,
netdev@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-kernel@vger.kernel.org, Trond.Myklebust@netapp.com,
neilb@suse.de, hch@infradead.org, michaelc@cs.wisc.edu,
emunson@mgebm.net
Subject: Re: [PATCH 01/12] netvm: Prevent a stream-specific deadlock
Date: Tue, 15 May 2012 11:08:29 +0100 [thread overview]
Message-ID: <20120515100829.GH29102@suse.de> (raw)
In-Reply-To: <1337075234.27694.9.camel@twins>
On Tue, May 15, 2012 at 11:47:14AM +0200, Peter Zijlstra wrote:
> On Tue, 2012-05-15 at 10:14 +0100, Mel Gorman wrote:
> > @@ -289,6 +289,18 @@ void sk_clear_memalloc(struct sock *sk)
> > sock_reset_flag(sk, SOCK_MEMALLOC);
> > sk->sk_allocation &= ~__GFP_MEMALLOC;
> > static_key_slow_dec(&memalloc_socks);
> > +
> > + /*
> > + * SOCK_MEMALLOC is allowed to ignore rmem limits to ensure forward
> > + * progress of swapping. However, if SOCK_MEMALLOC is cleared while
> > + * it has rmem allocations there is a risk that the user of the
> > + * socket cannot make forward progress due to exceeding the rmem
> > + * limits. By rights, sk_clear_memalloc() should only be called
> > + * on sockets being torn down but warn and reset the accounting if
> > + * that assumption breaks.
> > + */
> > + if (WARN_ON(sk->sk_forward_alloc))
>
> WARN_ON_ONCE() perhaps?
>
I do not expect SOCK_MEMALLOC to be cleared frequently at all with the
possible exception of swapon/swapoff stress tests. If the flag is being
cleared regularly with rmem tokens then that is interesting in itself
but a WARN_ON_ONCE would miss it.
> > + sk_mem_reclaim(sk);
> > }
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2012-05-15 10:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-10 13:54 [PATCH 00/12] Swap-over-NFS without deadlocking V4 Mel Gorman
2012-05-10 13:54 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-05-11 5:10 ` David Miller
2012-05-14 10:56 ` Mel Gorman
2012-05-14 20:26 ` David Miller
2012-05-15 9:14 ` Mel Gorman
2012-05-15 9:47 ` Peter Zijlstra
2012-05-15 10:08 ` Mel Gorman [this message]
2012-05-10 13:54 ` [PATCH 02/12] selinux: tag avc cache alloc as non-critical Mel Gorman
2012-05-10 14:14 ` Casey Schaufler
2012-05-10 14:25 ` Eric Paris
2012-05-10 13:54 ` [PATCH 03/12] mm: Methods for teaching filesystems about PG_swapcache pages Mel Gorman
2012-05-10 13:54 ` [PATCH 04/12] mm: Add support for a filesystem to activate swap files and use direct_IO for writing swap pages Mel Gorman
2012-05-10 13:54 ` [PATCH 05/12] mm: swap: Implement generic handler for swap_activate Mel Gorman
2012-05-10 13:54 ` [PATCH 06/12] mm: Add get_kernel_page[s] for pinning of kernel addresses for I/O Mel Gorman
2012-05-10 13:54 ` [PATCH 07/12] mm: Add support for direct_IO to highmem pages Mel Gorman
2012-05-10 13:54 ` [PATCH 08/12] nfs: teach the NFS client how to treat PG_swapcache pages Mel Gorman
2012-05-10 13:54 ` [PATCH 09/12] nfs: disable data cache revalidation for swapfiles Mel Gorman
2012-05-10 13:54 ` [PATCH 10/12] nfs: enable swap on NFS Mel Gorman
2012-05-10 13:54 ` [PATCH 11/12] nfs: Prevent page allocator recursions with swap over NFS Mel Gorman
2012-05-10 13:54 ` [PATCH 12/12] Avoid dereferencing bd_disk during swap_entry_free for network storage Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2012-05-17 14:51 [PATCH 00/12] Swap-over-NFS without deadlocking V5 Mel Gorman
2012-05-17 14:51 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-05-17 20:14 ` David Miller
2012-06-20 9:37 [PATCH 00/12] Swap-over-NFS without deadlocking V6 Mel Gorman
2012-06-20 9:37 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-06-20 14:21 ` Mel Gorman
2012-06-20 15:22 ` Rik van Riel
2012-06-22 14:30 [PATCH 00/12] Swap-over-NFS without deadlocking V7 Mel Gorman
2012-06-22 14:30 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-06-29 13:33 [PATCH 00/12] Swap-over-NFS without deadlocking V8 Mel Gorman
2012-06-29 13:33 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
2012-07-12 6:40 [PATCH 00/12] Swap-over-NFS without deadlocking V9 Mel Gorman
2012-07-12 6:40 ` [PATCH 01/12] netvm: Prevent a stream-specific deadlock Mel Gorman
Reply instructions:
You may reply publicly 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=20120515100829.GH29102@suse.de \
--to=mgorman@suse.de \
--cc=Trond.Myklebust@netapp.com \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=davem@davemloft.net \
--cc=emunson@mgebm.net \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nfs@vger.kernel.org \
--cc=michaelc@cs.wisc.edu \
--cc=neilb@suse.de \
--cc=netdev@vger.kernel.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).