* [Cluster-devel] [GFS2 PATCH] GFS2: Implement a "bitmap has no extents longer than X" scheme
[not found] <1176243906.15902430.1383584067330.JavaMail.root@redhat.com>
@ 2013-11-04 16:55 ` Bob Peterson
0 siblings, 0 replies; only message in thread
From: Bob Peterson @ 2013-11-04 16:55 UTC (permalink / raw)
To: cluster-devel.redhat.com
Hi,
Before this patch, we used a bit, GBF_FULL, to determine when a bitmap
was full. With the preceding patch, we started accepting block
reservations smaller than the ideal size, which requires a lot more
parsing of the bitmaps. To reduce the amount of bitmap searching, this
patch implements a scheme whereby each rgrp keeps track of the point
at this multi-block reservations will fail.
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 ba1ea67..48c1a85 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -68,7 +68,6 @@ struct gfs2_log_operations {
struct gfs2_bitmap {
struct buffer_head *bi_bh;
char *bi_clone;
- unsigned long bi_flags;
u32 bi_offset;
u32 bi_start;
u32 bi_len;
@@ -93,6 +92,7 @@ struct gfs2_rgrpd {
struct gfs2_rgrp_lvb *rd_rgl;
u32 rd_last_alloc;
u32 rd_flags;
+ u32 rd_extfail_pt; /* extent failure point */
#define GFS2_RDF_CHECK 0x10000000 /* check for unlinked inodes */
#define GFS2_RDF_UPTODATE 0x20000000 /* rg is up to date */
#define GFS2_RDF_ERROR 0x40000000 /* error in rg */
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 010b9fb..e615021 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -81,8 +81,8 @@ static void maybe_release_space(struct gfs2_bufdata *bd)
gfs2_rgrp_send_discards(sdp, rgd->rd_data0, bd->bd_bh, bi, 1, NULL);
memcpy(bi->bi_clone + bi->bi_offset,
bd->bd_bh->b_data + bi->bi_offset, bi->bi_len);
- clear_bit(GBF_FULL, &bi->bi_flags);
rgd->rd_free_clone = rgd->rd_free;
+ rgd->rd_extfail_pt = rgd->rd_free;
}
/**
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index ddcddce..7ded0fa 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -59,7 +59,7 @@
struct gfs2_extent {
struct gfs2_rbm ex_rbm;
- u32 ex_len;
+ u32 ex_len; /* unreserved extent length */
};
static const char valid_change[16] = {
@@ -636,13 +636,15 @@ static void __rs_deltree(struct gfs2_blkreserv *rs)
RB_CLEAR_NODE(&rs->rs_node);
if (rs->rs_free) {
- struct gfs2_bitmap *bi = rbm_bi(&rs->rs_rbm);
-
/* return reserved blocks to the rgrp */
BUG_ON(rs->rs_rbm.rgd->rd_reserved < rs->rs_free);
rs->rs_rbm.rgd->rd_reserved -= rs->rs_free;
+ /* The rgrp extent failure point is likely not to increase;
+ it will only do so if the freed blocks are somehow
+ contiguous with a span of free blocks that follows. Still,
+ it will force the number to be recalculated later. */
+ rgd->rd_extfail_pt += rs->rs_free;
rs->rs_free = 0;
- clear_bit(GBF_FULL, &bi->bi_flags);
smp_mb__after_clear_bit();
}
}
@@ -768,7 +770,6 @@ static int compute_bitstructs(struct gfs2_rgrpd *rgd)
for (x = 0; x < length; x++) {
bi = rgd->rd_bits + x;
- bi->bi_flags = 0;
/* small rgrp; bitmap stored completely in header block */
if (length == 1) {
bytes = bytes_left;
@@ -1127,11 +1128,11 @@ int gfs2_rgrp_bh_get(struct gfs2_rgrpd *rgd)
}
if (!(rgd->rd_flags & GFS2_RDF_UPTODATE)) {
- for (x = 0; x < length; x++)
- clear_bit(GBF_FULL, &rgd->rd_bits[x].bi_flags);
gfs2_rgrp_in(rgd, (rgd->rd_bits[0].bi_bh)->b_data);
rgd->rd_flags |= (GFS2_RDF_UPTODATE | GFS2_RDF_CHECK);
rgd->rd_free_clone = rgd->rd_free;
+ /* max out the rgrp allocation failure point */
+ rgd->rd_extfail_pt = rgd->rd_free;
}
if (be32_to_cpu(GFS2_MAGIC) != rgd->rd_rgl->rl_magic) {
rgd->rd_rgl->rl_unlinked = cpu_to_be32(count_unlinked(rgd));
@@ -1591,8 +1592,8 @@ fail:
* @ap: the allocation parameters
*
* Side effects:
- * - If looking for free blocks, we set GBF_FULL on each bitmap which
- * has no free blocks in it.
+ * - If looking for free blocks, we set rd_extfail_pt on each rgrp which
+ * has come up short on a free block search.
*
* Returns: 0 on success, -ENOSPC if there is no block of the requested state
*/
@@ -1603,7 +1604,8 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
{
struct buffer_head *bh;
int initial_bii;
- u32 initial_offset;
+ int first_bii = rbm->bii;
+ u32 first_offset = rbm->offset;
u32 offset;
u8 *buffer;
int n = 0;
@@ -1626,19 +1628,14 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
while(1) {
bi = rbm_bi(rbm);
- if (test_bit(GBF_FULL, &bi->bi_flags) &&
- (state == GFS2_BLKST_FREE))
- goto next_bitmap;
-
bh = bi->bi_bh;
buffer = bh->b_data + bi->bi_offset;
WARN_ON(!buffer_uptodate(bh));
if (state != GFS2_BLKST_UNLINKED && bi->bi_clone)
buffer = bi->bi_clone + bi->bi_offset;
- initial_offset = rbm->offset;
offset = gfs2_bitfit(buffer, bi->bi_len, rbm->offset, state);
if (offset == BFITNOENT)
- goto bitmap_full;
+ goto next_bitmap;
rbm->offset = offset;
if (ip == NULL)
return 0;
@@ -1661,12 +1658,6 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
}
return ret;
-bitmap_full: /* Mark bitmap as full and fall through */
- if ((state == GFS2_BLKST_FREE) && initial_offset == 0) {
- struct gfs2_bitmap *bi = rbm_bi(rbm);
- set_bit(GBF_FULL, &bi->bi_flags);
- }
-
next_bitmap: /* Find next bitmap in the rgrp */
rbm->offset = 0;
rbm->bii++;
@@ -1684,6 +1675,13 @@ next_iter:
if (minext == NULL || state != GFS2_BLKST_FREE)
return -ENOSPC;
+ /* If the extent was too small, and it's smaller than the smallest
+ to have failed before, remember for future reference that it's
+ useless to search this rgrp again for this amount or more. */
+ if ((first_offset == 0) && (first_bii == 0) &&
+ (*minext < rbm->rgd->rd_extfail_pt))
+ rbm->rgd->rd_extfail_pt = *minext;
+
/* If the maximum extent we found is big enough to fulfill the
minimum requirements, use it anyway. */
if (maxext.ex_len) {
@@ -1929,7 +1927,9 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
}
/* Skip unuseable resource groups */
- if (rs->rs_rbm.rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))
+ if ((rs->rs_rbm.rgd->rd_flags & (GFS2_RGF_NOALLOC |
+ GFS2_RDF_ERROR)) ||
+ (ap && (ap->target > rs->rs_rbm.rgd->rd_extfail_pt)))
goto skip_rgrp;
if (sdp->sd_args.ar_rgrplvb)
@@ -2111,10 +2111,10 @@ int gfs2_rgrp_dump(struct seq_file *seq, const struct gfs2_glock *gl)
if (rgd == NULL)
return 0;
- gfs2_print_dbg(seq, " R: n:%llu f:%02x b:%u/%u i:%u r:%u\n",
+ gfs2_print_dbg(seq, " R: n:%llu f:%02x b:%u/%u i:%u r:%u e:%u\n",
(unsigned long long)rgd->rd_addr, rgd->rd_flags,
rgd->rd_free, rgd->rd_free_clone, rgd->rd_dinodes,
- rgd->rd_reserved);
+ rgd->rd_reserved, rgd->rd_extfail_pt);
spin_lock(&rgd->rd_rsspin);
for (n = rb_first(&rgd->rd_rstree); n; n = rb_next(&trs->rs_node)) {
trs = rb_entry(n, struct gfs2_blkreserv, rs_node);
@@ -2233,9 +2233,9 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
/* Since all blocks are reserved in advance, this shouldn't happen */
if (error) {
- fs_warn(sdp, "inum=%llu error=%d, nblocks=%u, full=%d\n",
+ fs_warn(sdp, "inum=%llu error=%d, nblocks=%u, fail_pt=%d\n",
(unsigned long long)ip->i_no_addr, error, *nblocks,
- test_bit(GBF_FULL, &rbm.rgd->rd_bits->bi_flags));
+ rbm.rgd->rd_extfail_pt);
goto rgrp_error;
}
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