From: Mel Gorman <mgorman@techsingularity.net>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fs, pseudo: Do not update atime for pseudo inodes
Date: Fri, 19 Jun 2020 17:04:07 +0100 [thread overview]
Message-ID: <20200619160407.GL3183@techsingularity.net> (raw)
In-Reply-To: <CAOQ4uxjdTUnA2ACQtyZ95QkTtH_zaKZEYLyok73yjrhuUyXmtg@mail.gmail.com>
On Fri, Jun 19, 2020 at 04:45:09PM +0300, Amir Goldstein wrote:
> > proxy measure is the proc fd representations of such inodes which do not
> > appear to change once they are created. This patch sets the S_NOATIME
> > on inode->i_flags for inodes created by new_inode_pseudo() so that atime
> > will not be updated.
> >
>
> new_inode() calls new_inode_pseudo() ...
> You need to factor out a new helper.
>
You're right, it's broken as it stands. Even though I don't think direct
users of alloc_file_pseudo use simple_getattr, it doesn't matter.
> Either you can provide callers analysis of all new_inode_pseudo() users
> or use a new helper to set S_NOATIME and call it from the relevant users
> (pipe, socket).
>
Relevant users makes sense as it's less likely to cause surprises.
> How about S_NOCMTIME while you are at it?
> Doesn't file_update_time() show in profiling?
I can look into it, I don't recall seeing file_update_time() in the
profile but maybe it was just too small.
> Is there a valid use case for updating c/mtime of anonymous socket/pipe?
>
Not that I can think of but that could be a failure of imagination.
--
Mel Gorman
SUSE Labs
prev parent reply other threads:[~2020-06-19 16:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-17 14:53 [PATCH] fs, pseudo: Do not update atime for pseudo inodes Mel Gorman
2020-06-19 13:45 ` Amir Goldstein
2020-06-19 16:04 ` Mel Gorman [this message]
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