From: Al Viro <viro@ZenIV.linux.org.uk>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] namei: Remove unlikely annotation for revalidate check in lookup_fast()
Date: Tue, 7 Feb 2017 00:06:42 +0000 [thread overview]
Message-ID: <20170207000642.GH13195@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20170206171735.17d2a5c8@gandalf.local.home>
On Mon, Feb 06, 2017 at 05:17:35PM -0500, Steven Rostedt wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
>
> The likely/unlikely profiler showed that the unlikely around the
> dentry->d_flags & DCACHE_OP_REVALIDATE was wrong 95% of the time. Adding
> trace_printk()s, it revealed that the dentry ops had hooks to:
>
> kernfs_dop_revalidate
> pid_revalidate
> proc_sys_revalidate
> tid_fd_revalidate
>
> As tools today now access files that have these operations often, it's best
> just to remove the annotation, as it is more dependent on use cases and not
> normal mode of operation if it will be true or not.
"Tools" being what, exactly? What kind of load had that been measured on?
next prev parent reply other threads:[~2017-02-07 0:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-06 22:17 [PATCH] namei: Remove unlikely annotation for revalidate check in lookup_fast() Steven Rostedt
2017-02-07 0:06 ` Al Viro [this message]
2017-02-07 1:34 ` Steven Rostedt
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