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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jeff Layton <jlayton@primarydata.com>,
	Bruce Fields <bfields@fieldses.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	Tejun Heo <tj@kernel.org>, NeilBrown <neilb@suse.de>
Subject: Re: [PATCH v2 00/16] nfsd/sunrpc: add support for a workqueue-based nfsd
Date: Fri, 12 Dec 2014 03:02:06 +0000	[thread overview]
Message-ID: <20141212030206.GA22149@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFy_LRUzMO_ixgVtysr7OKs=GSk9dU1ORRUdrTn210VuyA@mail.gmail.com>

On Thu, Dec 11, 2014 at 06:29:37PM -0800, Linus Torvalds wrote:
> On Thu, Dec 11, 2014 at 6:12 PM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > Linus, do you see any problems with the following patch (against the mainline)?
> 
> Not concpetually, but create_kthread() uses CLONE_FS, and I don't
> think it's just umask that things like nfsd want to avoid sharing.
> What about all the *other* fields?
> 
> Just as an example: even if all the threads actually end up all having
> the same global root, what about contention on 'fs->lock'?
> 
> I have *not* looked at the details, and maybe there's some reason I'm
> completely off, but it worries me.

Umm...  I would be very surprised if it turned out to be a problem.
nfsd really doesn't give a fuck about its cwd and root - not in the
thread side of things.  And (un)exporting is (a) not on a hot path
and (b) not done from a kernel thread anyway.  fh_to_dentry and friends
doesn't care about root/cwd, etc.

I don't see anything that could cause that kind of issues.

  reply	other threads:[~2014-12-12  3:02 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-12-10 19:07 [PATCH v2 00/16] nfsd/sunrpc: add support for a workqueue-based nfsd Jeff Layton
2014-12-10 19:07 ` [PATCH v2 01/16] sunrpc: add a new svc_serv_ops struct and move sv_shutdown into it Jeff Layton
2014-12-10 19:07 ` [PATCH v2 02/16] sunrpc: move sv_function into sv_ops Jeff Layton
2014-12-10 19:07 ` [PATCH v2 03/16] sunrpc: move sv_module parm " Jeff Layton
2014-12-10 19:07 ` [PATCH v2 04/16] sunrpc: turn enqueueing a svc_xprt into a svc_serv operation Jeff Layton
2014-12-10 19:07 ` [PATCH v2 05/16] sunrpc: abstract out svc_set_num_threads to sv_ops Jeff Layton
2014-12-10 19:07 ` [PATCH v2 06/16] sunrpc: move pool_mode definitions into svc.h Jeff Layton
2014-12-10 19:07 ` [PATCH v2 07/16] sunrpc: factor svc_rqst allocation and freeing from sv_nrthreads refcounting Jeff Layton
2014-12-10 19:07 ` [PATCH v2 08/16] sunrpc: set up workqueue function in svc_xprt Jeff Layton
2014-12-10 19:07 ` [PATCH v2 09/16] sunrpc: set up svc_rqst work if it's defined Jeff Layton
2014-12-10 19:07 ` [PATCH v2 10/16] sunrpc: add basic support for workqueue-based services Jeff Layton
2014-12-10 19:07 ` [PATCH v2 11/16] nfsd: keep a reference to the fs_struct in svc_rqst Jeff Layton
2014-12-10 19:07 ` [PATCH v2 12/16] nfsd: add support for workqueue based service processing Jeff Layton
2014-12-10 19:07 ` [PATCH v2 13/16] sunrpc: keep a cache of svc_rqsts for each NUMA node Jeff Layton
2014-12-10 19:07 ` [PATCH v2 14/16] sunrpc: add more tracepoints around svc_xprt handling Jeff Layton
2014-12-10 19:07 ` [PATCH v2 15/16] sunrpc: print the svc_rqst pointer value in svc_process tracepoint Jeff Layton
2014-12-10 19:08 ` [PATCH v2 16/16] sunrpc: add tracepoints around svc_sock handling Jeff Layton
2014-12-10 22:31 ` [PATCH v2 00/16] nfsd/sunrpc: add support for a workqueue-based nfsd Chuck Lever
2014-12-10 23:13   ` Jeff Layton
2014-12-12  2:12 ` Al Viro
2014-12-12  2:29   ` Linus Torvalds
2014-12-12  3:02     ` Al Viro [this message]
2014-12-12  3:06       ` Al Viro
2014-12-12 11:54       ` Jeff Layton
2014-12-12 16:59         ` Al Viro
2014-12-13 14:06           ` Jeff Layton
2014-12-13 17:29             ` Al Viro
2014-12-12  2:52   ` Al Viro

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