From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [dm-devel] [PATCH 2/3] Introduce percpu rw semaphores Date: Wed, 1 Aug 2012 10:15:27 -0700 Message-ID: <20120801171527.GB2491@linux.vnet.ibm.com> References: <1343508252.2626.13184.camel@edumazet-glaptop> <20120730170013.GA4778@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org To: Mikulas Patocka Cc: Eric Dumazet , Jens Axboe , Andrea Arcangeli , Jan Kara , dm-devel@redhat.com, linux-kernel@vger.kernel.org, Jeff Moyer , Alexander Viro , kosaki.motohiro@jp.fujitsu.com, linux-fsdevel@vger.kernel.org, lwoodman@redhat.com, "Alasdair G. Kergon" List-Id: dm-devel.ids On Mon, Jul 30, 2012 at 08:00:19PM -0400, Mikulas Patocka wrote: > > > On Mon, 30 Jul 2012, Paul E. McKenney wrote: > > > On Sun, Jul 29, 2012 at 01:13:34AM -0400, Mikulas Patocka wrote: > > > On Sat, 28 Jul 2012, Eric Dumazet wrote: > > > > On Sat, 2012-07-28 at 12:41 -0400, Mikulas Patocka wrote: > > > > [ . . . ] > > > > > > (bdev->bd_block_size should be read exactly once ) > > > > > > Rewrite all direct and non-direct io code so that it reads block size just > > > once ... > > > > For whatever it is worth, the 3.5 Linux kernel only has about ten mentions > > of bd_block_size, at least according to cscope. > > plus 213 uses of i_blkbits (which is derived directly from bd_block_size). > 45 of them is in fs/*.c and mm/*.c At least it is only hundreds rather than thousands! ;-) Thanx, Paul