From: Christoph Hellwig <hch@lst.de>
To: Richard Weinberger <richard@nod.at>
Cc: viro@zeniv.linux.org.uk, dchinner@redhat.com, hch@lst.de,
eric.dumazet@gmail.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fs/inode: No need to take ->i_lock right after alloc_inode()
Date: Fri, 10 Jan 2014 10:22:29 +0100 [thread overview]
Message-ID: <20140110092229.GA556@lst.de> (raw)
In-Reply-To: <1524545.iNFYXWHlaf@sandpuppy>
On Wed, Jan 08, 2014 at 11:21:13AM +0100, Richard Weinberger wrote:
> > In all three cases, new_inode_pseudo(), iget_locked() and iget5_locked(),
> > we own the new inode exclusively at this point and therefore taking
> > ->i_lock to protect ->i_state/->i_hash against concurrent access is
> > superfluous.
We'd still need some sort of barrier to make sure the state is visible
to all CPUs before it becomes visible, usually by another spin_unlock
happing later. If you have a workload where removing these is critical
please document these issues in the code and resubmit it with an explanation
of the workload where it helps. If it's just a cleanup I wouldn't bother
with it.
next prev parent reply other threads:[~2014-01-10 9:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-14 20:54 [PATCH] fs/inode: No need to take ->i_lock right after alloc_inode() Richard Weinberger
2014-01-08 10:21 ` Richard Weinberger
2014-01-10 9:22 ` Christoph Hellwig [this message]
2014-01-10 9:48 ` Richard Weinberger
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