From: Thavatchai Makphaibulchoke Subject: Re: [PATCH v4 0/3] ext4: increase mbcache scalability Date: Fri, 24 Jan 2014 18:13:14 -0700 Message-ID: <52E30FAA.500@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: 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: Andi Kleen , T Makphaibulchoke Return-path: Received: from g1t0029.austin.hp.com ([15.216.28.36]:47620 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751157AbaAYHVj (ORCPT ); Sat, 25 Jan 2014 02:21:39 -0500 In-Reply-To: <87fvodcb65.fsf@tassilo.jf.intel.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 01/24/2014 02:38 PM, Andi Kleen wrote: > T Makphaibulchoke writes: > >> The patch consists of three parts. >> >> The first part changes the implementation of both the block and hash chains of >> an mb_cache from list_head to hlist_bl_head and also introduces new members, >> including a spinlock to mb_cache_entry, as required by the second part. > > spinlock per entry is usually overkill for larger hash tables. > > Can you use a second smaller lock table that just has locks and is > indexed by a subset of the hash key. Most likely a very small > table is good enough. > > Also I would be good to have some data on the additional memory consumption. > > -Andi > Thanks Andi for the comments. Will look into that. Thanks, Mak.