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Date: Mon, 4 Nov 2013 11:09:25 +0000 From: Steven Whitehouse <swhiteho@...hat.com> To: cluster-devel@...hat.com, linux-kernel@...r.kernel.org Cc: Bob Peterson <rpeterso@...hat.com>, Steven Whitehouse <swhiteho@...hat.com> Subject: [PATCH 02/19] GFS2: optimize rbm_from_block wrt bi_start From: Bob Peterson <rpeterso@...hat.com> In function gfs2_rbm_from_block, it starts by checking if the block falls within the first bitmap. It does so by checking if the rbm's offset is less than (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY. However, the first bitmap will always have bi_start==0. Therefore this is an unnecessary calculation in a function that gets called billions of times. This patch removes the reference to bi_start. Signed-off-by: Bob Peterson <rpeterso@...hat.com> Signed-off-by: Steven Whitehouse <swhiteho@...hat.com> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 6931743..7a6fa03 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -262,7 +262,7 @@ static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block) rbm->bi = rbm->rgd->rd_bits; rbm->offset = (u32)(rblock); /* Check if the block is within the first block */ - if (rbm->offset < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) + if (rbm->offset < rbm->bi->bi_len * GFS2_NBBY) return 0; /* Adjust for the size diff between gfs2_meta_header and gfs2_rgrp */ -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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