* [Cluster-devel] [GFS2 PATCH] GFS2: Speed up gfs2_rbm_from_block
@ 2012-10-17 15:06 Bob Peterson
2012-10-18 13:16 ` Steven Whitehouse
0 siblings, 1 reply; 2+ messages in thread
From: Bob Peterson @ 2012-10-17 15:06 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
This patch is a rewrite of function gfs2_rbm_from_block. Rather than
looping to find the right bitmap, the code now does a few simple
math calculations. This speeds up the function significantly.
Regards,
Bob Peterson
Red Hat File Systems
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 3d469d3..24bb0b8 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -621,6 +621,7 @@ struct gfs2_sbd {
u32 sd_hash_bsize_shift;
u32 sd_hash_ptrs; /* Number of pointers in a hash block */
u32 sd_qc_per_block;
+ u32 sd_blocks_per_bitmap;
u32 sd_max_dirres; /* Max blocks needed to add a directory entry */
u32 sd_max_height; /* Max height of a file's metadata tree */
u64 sd_heightsize[GFS2_MAX_META_HEIGHT + 1];
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index e443966..0e3554e 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -278,6 +278,9 @@ static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)
sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
sizeof(struct gfs2_meta_header)) /
sizeof(struct gfs2_quota_change);
+ sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize -
+ sizeof(struct gfs2_meta_header))
+ * GFS2_NBBY; /* not the rgrp bitmap, subsequent bitmaps only */
/* Compute maximum reservation required to add a entry to a directory */
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 43d1a20..7635500 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -250,23 +250,23 @@ static u32 gfs2_bitfit(const u8 *buf, const unsigned int len,
static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block)
{
- u64 rblock = block - rbm->rgd->rd_data0;
- u32 goal = (u32)rblock;
- int x;
+ u32 x;
- if (WARN_ON_ONCE(rblock > UINT_MAX))
- return -EINVAL;
if (block >= rbm->rgd->rd_data0 + rbm->rgd->rd_data)
return -E2BIG;
- for (x = 0; x < rbm->rgd->rd_length; x++) {
- rbm->bi = rbm->rgd->rd_bits + x;
- if (goal < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) {
- rbm->offset = goal - (rbm->bi->bi_start * GFS2_NBBY);
- break;
- }
- }
+ rbm->bi = rbm->rgd->rd_bits;
+ rbm->offset = (u32)(block - rbm->rgd->rd_data0);
+ /* Check if the block is within the first block */
+ if (rbm->offset < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY)
+ return 0;
+ /* Adjust for the size diff between gfs2_meta_header and gfs2_rgrp */
+ rbm->offset += (sizeof(struct gfs2_rgrp) -
+ sizeof(struct gfs2_meta_header)) * GFS2_NBBY;
+ x = rbm->offset / rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
+ rbm->offset -= x * rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
+ rbm->bi += x;
return 0;
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [Cluster-devel] [GFS2 PATCH] GFS2: Speed up gfs2_rbm_from_block
2012-10-17 15:06 [Cluster-devel] [GFS2 PATCH] GFS2: Speed up gfs2_rbm_from_block Bob Peterson
@ 2012-10-18 13:16 ` Steven Whitehouse
0 siblings, 0 replies; 2+ messages in thread
From: Steven Whitehouse @ 2012-10-18 13:16 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
On Wed, 2012-10-17 at 11:06 -0400, Bob Peterson wrote:
> Hi,
>
> This patch is a rewrite of function gfs2_rbm_from_block. Rather than
> looping to find the right bitmap, the code now does a few simple
> math calculations. This speeds up the function significantly.
>
It would be a good plan to include the timings that you showed me
yesterday in the patch description to show the improvement this gives.
> Regards,
>
> Bob Peterson
> Red Hat File Systems
>
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
> diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
> index 3d469d3..24bb0b8 100644
> --- a/fs/gfs2/incore.h
> +++ b/fs/gfs2/incore.h
> @@ -621,6 +621,7 @@ struct gfs2_sbd {
> u32 sd_hash_bsize_shift;
> u32 sd_hash_ptrs; /* Number of pointers in a hash block */
> u32 sd_qc_per_block;
> + u32 sd_blocks_per_bitmap;
> u32 sd_max_dirres; /* Max blocks needed to add a directory entry */
> u32 sd_max_height; /* Max height of a file's metadata tree */
> u64 sd_heightsize[GFS2_MAX_META_HEIGHT + 1];
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index e443966..0e3554e 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -278,6 +278,9 @@ static int gfs2_read_sb(struct gfs2_sbd *sdp, int silent)
> sdp->sd_qc_per_block = (sdp->sd_sb.sb_bsize -
> sizeof(struct gfs2_meta_header)) /
> sizeof(struct gfs2_quota_change);
> + sdp->sd_blocks_per_bitmap = (sdp->sd_sb.sb_bsize -
> + sizeof(struct gfs2_meta_header))
> + * GFS2_NBBY; /* not the rgrp bitmap, subsequent bitmaps only */
>
> /* Compute maximum reservation required to add a entry to a directory */
>
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 43d1a20..7635500 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -250,23 +250,23 @@ static u32 gfs2_bitfit(const u8 *buf, const unsigned int len,
>
> static int gfs2_rbm_from_block(struct gfs2_rbm *rbm, u64 block)
> {
> - u64 rblock = block - rbm->rgd->rd_data0;
> - u32 goal = (u32)rblock;
> - int x;
> + u32 x;
>
> - if (WARN_ON_ONCE(rblock > UINT_MAX))
> - return -EINVAL;
This test was intended to check for underflow, i.e. that the block
number was less than rd_data0. I think it would be a good plan to retain
such a test even though we should not see any blocks outside of the
current bitmap.
Otherwise, it looks good,
Steve.
> if (block >= rbm->rgd->rd_data0 + rbm->rgd->rd_data)
> return -E2BIG;
>
> - for (x = 0; x < rbm->rgd->rd_length; x++) {
> - rbm->bi = rbm->rgd->rd_bits + x;
> - if (goal < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY) {
> - rbm->offset = goal - (rbm->bi->bi_start * GFS2_NBBY);
> - break;
> - }
> - }
> + rbm->bi = rbm->rgd->rd_bits;
> + rbm->offset = (u32)(block - rbm->rgd->rd_data0);
> + /* Check if the block is within the first block */
> + if (rbm->offset < (rbm->bi->bi_start + rbm->bi->bi_len) * GFS2_NBBY)
> + return 0;
>
> + /* Adjust for the size diff between gfs2_meta_header and gfs2_rgrp */
> + rbm->offset += (sizeof(struct gfs2_rgrp) -
> + sizeof(struct gfs2_meta_header)) * GFS2_NBBY;
> + x = rbm->offset / rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
> + rbm->offset -= x * rbm->rgd->rd_sbd->sd_blocks_per_bitmap;
> + rbm->bi += x;
> return 0;
> }
>
>
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