From: Thavatchai Makphaibulchoke Subject: Re: [PATCH v4 0/3] ext4: increase mbcache scalability Date: Sun, 09 Feb 2014 12:46:41 -0700 Message-ID: <52F7DB21.2050204@hp.com> References: <1377186876-57291-1-git-send-email-tmac@hp.com> <1390588288-66930-1-git-send-email-tmac@hp.com> <87fvodcb65.fsf@tassilo.jf.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: T Makphaibulchoke , "viro@zeniv.linux.org.uk" , "tytso@mit.edu" , "adilger.kernel@dilger.ca" , "linux-ext4@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "aswin@hp.com" To: Andreas Dilger , Andi Kleen Return-path: Received: from g4t0015.houston.hp.com ([15.201.24.18]:6830 "EHLO g4t0015.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752090AbaBJBzp (ORCPT ); Sun, 9 Feb 2014 20:55:45 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 01/24/2014 11:09 PM, Andreas Dilger wrote: > I think the ext4 block groups are locked with the blockgroup_lock that has about the same number of locks as the number of cores, with a max of 128, IIRC. See blockgroup_lock.h. > > While there is some chance of contention, it is also unlikely that all of the cores are locking this area at the same time. > > Cheers, Andreas >