From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Sandeen Subject: Re: [PATCH] ext4: don't load the block bitmap for block groups which have no space Date: Mon, 13 Aug 2012 11:02:08 -0500 Message-ID: <50292500.1070807@redhat.com> References: <20120809181059.A5BAA11FC69@bugzilla.kernel.org> <1344622885-14982-1-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Ext4 Developers List To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:25735 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733Ab2HMQCL (ORCPT ); Mon, 13 Aug 2012 12:02:11 -0400 In-Reply-To: <1344622885-14982-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 8/10/12 1:21 PM, Theodore Ts'o wrote: > Add a short circuit check to ext4_mb_group_group() so that we don't > bother to load the block bitmap for a block group which does not have > any space available. (Or which does not have enough space until we > are in desperation mode, i.e., when cr == 3.) > > Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=45741 > Reported-by: mirek@me.com > Signed-off-by: "Theodore Ts'o" Looks ok to me; I think this just further optimizes what was done in 8a57d9d61a6e361c7bb159dda797672c1df1a691 ext4: check for a good block group before loading buddy pages correct? -Eric > --- > fs/ext4/mballoc.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 8eae947..3a57975 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -1862,6 +1862,12 @@ static int ext4_mb_good_group(struct ext4_allocation_context *ac, > > BUG_ON(cr < 0 || cr >= 4); > > + free = grp->bb_free; > + if (free == 0) > + return 0; > + if (cr <= 2 && free < ac->ac_g_ex.fe_len) > + return 0; > + > /* We only do this if the grp has never been initialized */ > if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) { > int ret = ext4_mb_init_group(ac->ac_sb, group); > @@ -1869,10 +1875,7 @@ static int ext4_mb_good_group(struct ext4_allocation_context *ac, > return 0; > } > > - free = grp->bb_free; > fragments = grp->bb_fragments; > - if (free == 0) > - return 0; > if (fragments == 0) > return 0; > >