From: Ted Ts'o Subject: Re: [PATCH] ext4: add more tracepoints and change to use MAJOR/MINOR dev macros Date: Mon, 21 Mar 2011 21:50:27 -0400 Message-ID: <20110322015027.GB3907@thunk.org> References: <20110318021325.85D814206C@ruihe.smo.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Jiaying Zhang Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:53556 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756269Ab1CVBua (ORCPT ); Mon, 21 Mar 2011 21:50:30 -0400 Content-Disposition: inline In-Reply-To: <20110318021325.85D814206C@ruihe.smo.corp.google.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Added to the ext4 patch queue. After running pahole, though, I'm still noticing a lot of holes in the ftrace structures: struct ftrace_raw_ext4_load_inode { struct trace_entry ent; /* 0 12 */ /* XXX 4 bytes hole, try to pack */ ino_t ino; /* 16 8 */ dev_t dev; /* 24 4 */ char __data[0]; /* 28 0 */ /* size: 32, cachelines: 1 */ /* sum members: 24, holes: 1, sum holes: 4 */ /* padding: 4 */ /* last cacheline: 32 bytes */ }; /* definitions: 1 */ Simply by swapping the ino and dev fields means that we'll save 4 bytes for this event. - Ted On Thu, Mar 17, 2011 at 07:13:25PM -0700, Jiaying Zhang wrote: > ext4: add more tracepoints and change to use MAJOR/MINOR dev macros > > - Add more ext4 tracepoints. > - Change ext4 tracepoints to use dev_t field with MAJOR/MINOR macros > so that we can save 4 bytes on certain platforms. > - Add sync_mode to ext4_da_writepages, ext4_da_write_pages, and > ext4_da_writepages_result tracepoints. Also remove for_reclaim > field from ext4_da_writepages since it is usually not very useful. > > Signed-off-by: Jiaying Zhang