From: jing zhang Subject: [PATCH 1/2] ext4: try to relieve ext4_mb_discard_group_preallocations() from hard work in simple way Date: Thu, 25 Mar 2010 23:24:13 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: "Theodore Ts'o" , Andreas Dilger , Dave Kleikamp , "Aneesh Kumar K. V" To: linux-ext4 Return-path: Received: from mail-iw0-f182.google.com ([209.85.223.182]:34269 "EHLO mail-iw0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753528Ab0CYPYO (ORCPT ); Thu, 25 Mar 2010 11:24:14 -0400 Received: by iwn12 with SMTP id 12so7421689iwn.21 for ; Thu, 25 Mar 2010 08:24:14 -0700 (PDT) Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Jing Zhang Date: Wed Mar 25 23:15:06 2010 The function, ext4_mb_discard_group_preallocations(), works alone as hard as possible without correct understanding its caller's good thinking. And now try to relieve it in simple way. But the variable, free, may be replaced with freed. Cc: Theodore Ts'o Cc: Andreas Dilger Cc: Dave Kleikamp Cc: "Aneesh Kumar K. V" Signed-off-by: Jing Zhang --- --- linux-2.6.32/fs/ext4/mballoc.c 2009-12-03 11:51:22.000000000 +0800 +++ ext4_mm_leak/mballoc-11-1.c 2010-03-25 23:06:00.000000000 +0800 @@ -3633,7 +3633,7 @@ repeat: spin_lock(&pa->pa_lock); if (atomic_read(&pa->pa_count)) { spin_unlock(&pa->pa_lock); - busy = 1; + busy += 1; continue; } if (pa->pa_deleted) { @@ -3654,7 +3654,7 @@ repeat: } /* if we still need more blocks and some PAs were used, try again */ - if (free < needed && busy) { + if (free < needed && needed <= free + busy) { busy = 0; ext4_unlock_group(sb, group); /*