From: Eric Dumazet <eric.dumazet@gmail.com>
To: NeilBrown <neilb@suse.de>
Cc: linux-mm@kvack.org, linux-nfs@vger.kernel.org,
linux-kernel@vger.kernel.org, xfs@oss.sgi.com,
netdev@vger.kernel.org
Subject: Re: [PATCH 10/19] NET: set PF_FSTRANS while holding sk_lock
Date: Tue, 15 Apr 2014 22:13:46 -0700 [thread overview]
Message-ID: <1397625226.4222.113.camel@edumazet-glaptop2.roam.corp.google.com> (raw)
In-Reply-To: <20140416040336.10604.96000.stgit@notabene.brown>
On Wed, 2014-04-16 at 14:03 +1000, NeilBrown wrote:
> sk_lock can be taken while reclaiming memory (in nfsd for loop-back
> NFS mounts, and presumably in nfs), and memory can be allocated while
> holding sk_lock, at least via:
>
> inet_listen -> inet_csk_listen_start ->reqsk_queue_alloc
>
> So to avoid deadlocks, always set PF_FSTRANS while holding sk_lock.
>
> This deadlock was found by lockdep.
Wow, this is adding expensive stuff in fast path, only for nfsd :(
BTW, why should the current->flags should be saved on a socket field,
and not a current->save_flags. This really looks a thread property, not
a socket one.
Why nfsd could not have PF_FSTRANS in its current->flags ?
For applications handling millions of sockets, this makes a difference.
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next prev parent reply other threads:[~2014-04-16 5:13 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-16 4:03 [PATCH/RFC 00/19] Support loop-back NFS mounts NeilBrown
2014-04-16 4:03 ` [PATCH 10/19] NET: set PF_FSTRANS while holding sk_lock NeilBrown
2014-04-16 5:13 ` Eric Dumazet [this message]
2014-04-16 5:47 ` NeilBrown
2014-04-16 13:00 ` David Miller
2014-04-17 2:38 ` NeilBrown
2014-04-16 4:03 ` [PATCH 14/19] driver core: set PF_FSTRANS while holding gdp_mutex NeilBrown
2014-04-16 4:03 ` [PATCH 11/19] FS: set PF_FSTRANS while holding mmap_sem in exec.c NeilBrown
2014-04-16 4:03 ` [PATCH 09/19] XFS: ensure xfs_file_*_read cannot deadlock in memory allocation NeilBrown
2014-04-16 6:04 ` Dave Chinner
2014-04-16 6:27 ` NeilBrown
2014-04-16 6:31 ` Dave Chinner
2014-04-16 4:03 ` [PATCH 02/19] lockdep: lockdep_set_current_reclaim_state should save old value NeilBrown
2014-04-16 4:03 ` [PATCH 07/19] nfsd and VM: use PF_LESS_THROTTLE to avoid throttle in shrink_inactive_list NeilBrown
2014-04-16 4:03 ` [PATCH 13/19] MM: set PF_FSTRANS while allocating per-cpu memory to avoid deadlock NeilBrown
2014-04-16 5:49 ` Dave Chinner
2014-04-16 6:22 ` NeilBrown
2014-04-16 6:30 ` Dave Chinner
2014-04-16 4:03 ` [PATCH 08/19] Set PF_FSTRANS while write_cache_pages calls ->writepage NeilBrown
2014-04-16 4:03 ` [PATCH 03/19] lockdep: improve scenario messages for RECLAIM_FS errors NeilBrown
2014-04-16 7:22 ` Peter Zijlstra
2014-04-16 4:03 ` [PATCH 06/19] nfsd: set PF_FSTRANS for nfsd threads NeilBrown
2014-04-16 7:28 ` Peter Zijlstra
2014-04-16 4:03 ` [PATCH 04/19] Make effect of PF_FSTRANS to disable __GFP_FS universal NeilBrown
2014-04-16 5:37 ` Dave Chinner
2014-04-16 6:17 ` NeilBrown
2014-04-17 1:03 ` NeilBrown
2014-04-17 4:41 ` Dave Chinner
2014-04-16 4:03 ` [PATCH 05/19] SUNRPC: track whether a request is coming from a loop-back interface NeilBrown
2014-04-16 14:47 ` Jeff Layton
2014-04-16 23:25 ` NeilBrown
2014-04-16 4:03 ` [PATCH 01/19] Promote current_{set, restore}_flags_nested from xfs to global NeilBrown
2014-04-16 4:03 ` [PATCH 12/19] NET: set PF_FSTRANS while holding rtnl_lock NeilBrown
2014-04-16 4:03 ` [PATCH 15/19] nfsd: set PF_FSTRANS when client_mutex is held NeilBrown
2014-04-16 4:03 ` [PATCH 18/19] nfsd: set PF_FSTRANS during nfsd4_do_callback_rpc NeilBrown
2014-04-16 4:03 ` [PATCH 19/19] XFS: set PF_FSTRANS while ilock is held in xfs_free_eofblocks NeilBrown
2014-04-16 6:18 ` Dave Chinner
2014-04-16 4:03 ` [PATCH 17/19] VFS: set PF_FSTRANS while namespace_sem is held NeilBrown
2014-04-16 4:46 ` Al Viro
2014-04-16 5:52 ` NeilBrown
[not found] ` <20140416155230.4d02e4b9-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
2014-04-16 16:37 ` Al Viro
2014-04-16 4:03 ` [PATCH 16/19] VFS: use GFP_NOFS rather than GFP_KERNEL in __d_alloc NeilBrown
2014-04-16 6:25 ` Dave Chinner
2014-04-16 6:49 ` NeilBrown
2014-04-16 9:00 ` Dave Chinner
2014-04-17 0:51 ` NeilBrown
2014-04-17 5:58 ` Dave Chinner
2014-04-16 14:42 ` [PATCH/RFC 00/19] Support loop-back NFS mounts Jeff Layton
2014-04-17 0:20 ` NeilBrown
2014-04-17 1:27 ` Dave Chinner
2014-04-17 1:50 ` NeilBrown
2014-04-17 4:23 ` Dave Chinner
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