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From: "Frank Ch. Eigler" <fche@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: Excessive stall times on ext4 in 3.9-rc2
Date: Mon, 8 Apr 2013 06:52:53 -0400	[thread overview]
Message-ID: <20130408105253.GA5275@redhat.com> (raw)
In-Reply-To: <20130408083645.GC2623@suse.de>

Hi, Mel -

> > [...]  git kernel developers
> > should use git systemtap, as has always been the case.  [...]
> 
> At one point in the past this used to be the case but then systemtap had to
> be compiled as part of automated tests across different kernel versions. It
> could have been worked around in various ways or even installed manually
> when machines were deployed but stap-fix.sh generally took less time to
> keep working.

OK, if that works for you.  Keep in mind though that newer versions of
systemtap retain backward-compatibility for ancient versions of the
kernel, so git systemtap should work on those older versions just
fine.


> [...]
> Yes, this was indeed the problem. The next version of watch-dstate.pl
> treated get_request_wait() as a function that may or may not exist. It
> uses /proc/kallsyms to figure it out.

... or you can use the "?" punctuation in the script to have
systemtap adapt:

    probe kprobe.function("get_request_wait") ?  { ... }


- FChE

WARNING: multiple messages have this Message-ID (diff)
From: "Frank Ch. Eigler" <fche@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Theodore Ts'o <tytso@mit.edu>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>
Subject: Re: Excessive stall times on ext4 in 3.9-rc2
Date: Mon, 8 Apr 2013 06:52:53 -0400	[thread overview]
Message-ID: <20130408105253.GA5275@redhat.com> (raw)
In-Reply-To: <20130408083645.GC2623@suse.de>

Hi, Mel -

> > [...]  git kernel developers
> > should use git systemtap, as has always been the case.  [...]
> 
> At one point in the past this used to be the case but then systemtap had to
> be compiled as part of automated tests across different kernel versions. It
> could have been worked around in various ways or even installed manually
> when machines were deployed but stap-fix.sh generally took less time to
> keep working.

OK, if that works for you.  Keep in mind though that newer versions of
systemtap retain backward-compatibility for ancient versions of the
kernel, so git systemtap should work on those older versions just
fine.


> [...]
> Yes, this was indeed the problem. The next version of watch-dstate.pl
> treated get_request_wait() as a function that may or may not exist. It
> uses /proc/kallsyms to figure it out.

... or you can use the "?" punctuation in the script to have
systemtap adapt:

    probe kprobe.function("get_request_wait") ?  { ... }


- FChE

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  reply	other threads:[~2013-04-08 10:54 UTC|newest]

Thread overview: 105+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-02 14:27 Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-02 14:27 ` Mel Gorman
2013-04-02 15:00 ` Jiri Slaby
2013-04-02 15:00   ` Jiri Slaby
2013-04-02 15:03 ` Zheng Liu
2013-04-02 15:03   ` Zheng Liu
2013-04-02 15:15   ` Mel Gorman
2013-04-02 15:15     ` Mel Gorman
2013-04-02 15:06 ` Theodore Ts'o
2013-04-02 15:06   ` Theodore Ts'o
2013-04-02 15:14   ` Theodore Ts'o
2013-04-02 15:14     ` Theodore Ts'o
2013-04-02 18:19     ` Theodore Ts'o
2013-04-02 18:19       ` Theodore Ts'o
2013-04-07 21:59       ` Frank Ch. Eigler
2013-04-07 21:59         ` Frank Ch. Eigler
2013-04-08  8:36         ` Mel Gorman
2013-04-08  8:36           ` Mel Gorman
2013-04-08 10:52           ` Frank Ch. Eigler [this message]
2013-04-08 10:52             ` Frank Ch. Eigler
2013-04-08 11:01         ` Theodore Ts'o
2013-04-08 11:01           ` Theodore Ts'o
2013-04-03 10:19     ` Mel Gorman
2013-04-03 10:19       ` Mel Gorman
2013-04-03 12:05       ` Theodore Ts'o
2013-04-03 12:05         ` Theodore Ts'o
2013-04-03 15:15         ` Mel Gorman
2013-04-05 22:18       ` Jiri Slaby
2013-04-05 22:18         ` Jiri Slaby
2013-04-05 23:16         ` Theodore Ts'o
2013-04-05 23:16           ` Theodore Ts'o
2013-04-06  7:29           ` Jiri Slaby
2013-04-06  7:29             ` Jiri Slaby
2013-04-06  7:37             ` Jiri Slaby
2013-04-06  7:37               ` Jiri Slaby
2013-04-06  8:19               ` Jiri Slaby
2013-04-06 13:15             ` Theodore Ts'o
2013-04-06 13:15               ` Theodore Ts'o
2013-04-10 10:56   ` Mel Gorman
2013-04-10 10:56     ` Mel Gorman
2013-04-10 13:12     ` Theodore Ts'o
2013-04-10 13:12       ` Theodore Ts'o
2013-04-11 17:04       ` Mel Gorman
2013-04-11 17:04         ` Mel Gorman
2013-04-11 18:35         ` Theodore Ts'o
2013-04-11 18:35           ` Theodore Ts'o
2013-04-11 21:33           ` Jan Kara
2013-04-11 21:33             ` Jan Kara
2013-04-12  2:57             ` Theodore Ts'o
2013-04-12  2:57               ` Theodore Ts'o
2013-04-12  4:50               ` Dave Chinner
2013-04-12  4:50                 ` Dave Chinner
2013-04-12 15:19                 ` Theodore Ts'o
2013-04-12 15:19                   ` Theodore Ts'o
2013-04-13  1:23                   ` Dave Chinner
2013-04-13  1:23                     ` Dave Chinner
2013-04-22 14:38                   ` Mel Gorman
2013-04-22 14:38                     ` Mel Gorman
2013-04-22 22:42                     ` Jeff Moyer
2013-04-22 22:42                       ` Jeff Moyer
2013-04-23  0:02                       ` Theodore Ts'o
2013-04-23  0:02                         ` Theodore Ts'o
2013-04-23  9:31                       ` Jan Kara
2013-04-23  9:31                         ` Jan Kara
2013-04-23 14:01                       ` Mel Gorman
2013-04-23 14:01                         ` Mel Gorman
2013-04-24 19:09                         ` Jeff Moyer
2013-04-24 19:09                           ` Jeff Moyer
2013-04-25 12:21                           ` Mel Gorman
2013-04-25 12:21                             ` Mel Gorman
2013-04-12  9:47               ` Mel Gorman
2013-04-12  9:47                 ` Mel Gorman
2013-04-21  0:05                 ` Theodore Ts'o
2013-04-21  0:05                   ` Theodore Ts'o
2013-04-21  0:07                   ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Theodore Ts'o
2013-04-21  0:07                     ` Theodore Ts'o
2013-04-21  0:07                     ` [PATCH 2/3] buffer: add BH_Prio and BH_Meta flags Theodore Ts'o
2013-04-21  0:07                       ` Theodore Ts'o
2013-04-21  0:07                     ` [PATCH 3/3] ext4: mark metadata blocks using bh flags Theodore Ts'o
2013-04-21  0:07                       ` Theodore Ts'o
2013-04-21  6:09                       ` Jiri Slaby
2013-04-21  6:09                         ` Jiri Slaby
2013-04-21  6:09                         ` Jiri Slaby
2013-04-21 19:55                         ` Theodore Ts'o
2013-04-21 19:55                           ` Theodore Ts'o
2013-04-21 19:55                           ` Theodore Ts'o
2013-04-21 20:48                           ` [PATCH 3/3 -v2] " Theodore Ts'o
2013-04-21 20:48                             ` Theodore Ts'o
2013-04-21 20:48                             ` Theodore Ts'o
2013-04-22 12:06                     ` [PATCH 1/3] ext4: mark all metadata I/O with REQ_META Zheng Liu
2013-04-22 12:06                       ` Zheng Liu
2013-04-23 15:33                   ` Excessive stall times on ext4 in 3.9-rc2 Mel Gorman
2013-04-23 15:33                     ` Mel Gorman
2013-04-23 15:50                     ` Theodore Ts'o
2013-04-23 15:50                       ` Theodore Ts'o
2013-04-23 16:13                       ` Mel Gorman
2013-04-23 16:13                         ` Mel Gorman
2013-04-12 10:18               ` Tvrtko Ursulin
2013-04-12 10:18                 ` Tvrtko Ursulin
2013-04-12  9:45           ` Mel Gorman
2013-04-12  9:45             ` Mel Gorman
2013-04-02 23:16 ` Theodore Ts'o
2013-04-02 23:16   ` Theodore Ts'o
2013-04-03 15:22   ` Mel Gorman
2013-04-03 15:22     ` Mel Gorman

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