linux-ext4 - Re: tracepoints in ext4 (and/or ext3?)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <48A23C0C.1070204@redhat.com>
Date:	Tue, 12 Aug 2008 20:42:36 -0500
From:	Eric Sandeen <sandeen@...hat.com>
To:	Theodore Tso <tytso@....edu>
CC:	"Jose R. Santos" <jrs@...ibm.com>,
	ext4 development <linux-ext4@...r.kernel.org>
Subject: Re: tracepoints in ext4 (and/or ext3?)

Theodore Tso wrote:
> On Tue, Aug 12, 2008 at 08:19:54AM -0500, Jose R. Santos wrote:
>> Good idea, although Im not sure if ext[34] is the best place we should
>> start putting markers though.
> 
> I can think of ext3/4 specific markers that would be useful for people
> who are tuning our filesystems for performance.  This would include
> when we start and end tranactions, when we force a checkpoint, when we
> create and, extend, and finish using a handle in the jbd layer.

Yep this is the kind of thing I thought of at first ...

> In the ext4 itself, knowing when we are mapping delayed allocations
> would be useful, as well as when we freeze and unfreeze a filesystem
> (i.e., for snapshots).

I could imagine even things like when/where/how big each allocation is,
also maybe some things in the lookup paths...

We might even be able to ditch the mballoc history in favor of
tracepoints if desired?

-Eric

> There are a lot of other tracepoints that probably do make more sense
> to be put in the VFS layer, although on thing that would be *really*
> nice is some semantic sugar in Systemtap or in a Systemtap tapset so
> that we only trigger the tracepoints for a particular filesystem.
> 
>      	     	     	 	     	   - Ted

--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html