From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Omar Sandoval <osandov@osandov.com>, Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
David Sterba <dsterba@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/8] swap: lock i_mutex for swap_writepage direct_IO
Date: Wed, 17 Dec 2014 00:24:37 -0800 [thread overview]
Message-ID: <20141217082437.GA9301@infradead.org> (raw)
In-Reply-To: <20141217082020.GH22149@ZenIV.linux.org.uk>
On Wed, Dec 17, 2014 at 08:20:21AM +0000, Al Viro wrote:
> Where the hell would those other references come from? We open the damn
> thing in sys_swapon(), never put it into descriptor tables, etc. and
> the only reason why we use filp_close() instead of fput() is that we
> would miss ->flush() otherwise.
>
> Said that, why not simply *open* it with O_DIRECT to start with and be done
> with that? It's not as if those guys came preopened by caller - swapon(2)
> gets a pathname and does opening itself.
Oops, should have dug deeper into the code. For some reason I assumed
the fd is passed in from userspace.
The suggestion from Al is much better, given that we never do normal
I/O on the swapfile, just the bmap + direct bio submission which I hope
could go away in favor of the direct I/O variant in the long run.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Omar Sandoval <osandov@osandov.com>, Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Trond Myklebust <trond.myklebust@primarydata.com>,
David Sterba <dsterba@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/8] swap: lock i_mutex for swap_writepage direct_IO
Date: Wed, 17 Dec 2014 00:24:37 -0800 [thread overview]
Message-ID: <20141217082437.GA9301@infradead.org> (raw)
In-Reply-To: <20141217082020.GH22149@ZenIV.linux.org.uk>
On Wed, Dec 17, 2014 at 08:20:21AM +0000, Al Viro wrote:
> Where the hell would those other references come from? We open the damn
> thing in sys_swapon(), never put it into descriptor tables, etc. and
> the only reason why we use filp_close() instead of fput() is that we
> would miss ->flush() otherwise.
>
> Said that, why not simply *open* it with O_DIRECT to start with and be done
> with that? It's not as if those guys came preopened by caller - swapon(2)
> gets a pathname and does opening itself.
Oops, should have dug deeper into the code. For some reason I assumed
the fd is passed in from userspace.
The suggestion from Al is much better, given that we never do normal
I/O on the swapfile, just the bmap + direct bio submission which I hope
could go away in favor of the direct I/O variant in the long run.
--
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next prev parent reply other threads:[~2014-12-17 8:24 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-15 5:26 [PATCH 0/8] clean up and generalize swap-over-NFS Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 5:26 ` [PATCH 1/8] nfs: follow direct I/O write locking convention Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 12:49 ` Trond Myklebust
2014-12-15 12:49 ` Trond Myklebust
2014-12-15 15:42 ` Omar Sandoval
2014-12-15 15:42 ` Omar Sandoval
2014-12-15 5:26 ` [PATCH 2/8] swap: lock i_mutex for swap_writepage direct_IO Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 16:27 ` Jan Kara
2014-12-15 16:27 ` Jan Kara
2014-12-15 16:56 ` Christoph Hellwig
2014-12-15 16:56 ` Christoph Hellwig
2014-12-15 22:11 ` Omar Sandoval
2014-12-15 22:11 ` Omar Sandoval
2014-12-16 8:35 ` Christoph Hellwig
2014-12-16 8:35 ` Christoph Hellwig
2014-12-16 8:35 ` Christoph Hellwig
2014-12-16 8:56 ` Omar Sandoval
2014-12-16 8:56 ` Omar Sandoval
2014-12-17 8:06 ` Christoph Hellwig
2014-12-17 8:06 ` Christoph Hellwig
2014-12-17 8:20 ` Al Viro
2014-12-17 8:20 ` Al Viro
2014-12-17 8:24 ` Christoph Hellwig [this message]
2014-12-17 8:24 ` Christoph Hellwig
2014-12-17 14:58 ` Omar Sandoval
2014-12-17 14:58 ` Omar Sandoval
2014-12-17 18:52 ` Christoph Hellwig
2014-12-17 18:52 ` Christoph Hellwig
2014-12-17 22:03 ` Al Viro
2014-12-17 22:03 ` Al Viro
2014-12-19 6:24 ` Omar Sandoval
2014-12-19 6:24 ` Omar Sandoval
2014-12-19 6:28 ` Al Viro
2014-12-19 6:28 ` Al Viro
2014-12-19 6:28 ` Al Viro
2014-12-20 6:51 ` Al Viro
2014-12-20 6:51 ` Al Viro
2014-12-22 7:26 ` Omar Sandoval
2014-12-22 7:26 ` Omar Sandoval
2014-12-23 9:37 ` Christoph Hellwig
2014-12-23 9:37 ` Christoph Hellwig
2014-12-23 9:37 ` Christoph Hellwig
2014-12-15 5:26 ` [PATCH 3/8] swap: don't add ITER_BVEC flag to direct_IO rw Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 6:16 ` Al Viro
2014-12-15 6:16 ` Al Viro
2014-12-15 15:57 ` Omar Sandoval
2014-12-15 15:57 ` Omar Sandoval
2014-12-15 5:26 ` [PATCH 4/8] iov_iter: add iov_iter_bvec and convert callers Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 5:26 ` [PATCH 5/8] direct-io: don't dirty ITER_BVEC pages on read Omar Sandoval
2014-12-15 5:26 ` Omar Sandoval
2014-12-15 5:27 ` [PATCH 6/8] nfs: don't dirty ITER_BVEC pages read through direct I/O Omar Sandoval
2014-12-15 5:27 ` Omar Sandoval
2014-12-15 6:17 ` Al Viro
2014-12-15 6:17 ` Al Viro
2014-12-15 5:27 ` [PATCH 7/8] swap: use direct I/O for SWP_FILE swap_readpage Omar Sandoval
2014-12-15 5:27 ` Omar Sandoval
2014-12-15 5:27 ` [PATCH 8/8] vfs: update swap_{,de}activate documentation Omar Sandoval
2014-12-15 5:27 ` Omar Sandoval
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