Messages in this thread | | | Date | Mon, 6 Feb 2017 20:34:15 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] namei: Remove unlikely annotation for revalidate check in lookup_fast() |
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On Tue, 7 Feb 2017 00:06:42 +0000 Al Viro <viro@ZenIV.linux.org.uk> wrote:
> 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?
I first saw it on my system that I ran for 3 weeks. But I investigated it more on a test box that was mostly idle. On the test box the "tools" was mostly systemd and journald. I can look deeper into it if you like.
-- Steve
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