From: Andi Kleen Subject: Re: [PATCH v4 0/3] ext4: increase mbcache scalability Date: Fri, 24 Jan 2014 13:38:58 -0800 Message-ID: <87fvodcb65.fsf@tassilo.jf.intel.com> References: <1377186876-57291-1-git-send-email-tmac@hp.com> <1390588288-66930-1-git-send-email-tmac@hp.com> Mime-Version: 1.0 Content-Type: text/plain 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: T Makphaibulchoke Return-path: In-Reply-To: <1390588288-66930-1-git-send-email-tmac@hp.com> (T. Makphaibulchoke's message of "Fri, 24 Jan 2014 11:31:25 -0700") Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 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 -- ak@linux.intel.com -- Speaking for myself only