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authorBob Peterson <rpeterso@redhat.com>2014-10-29 16:02:28 +0300
committerSteven Whitehouse <swhiteho@redhat.com>2014-11-03 22:24:49 +0300
commit0e27c18c30f6850ecd0fb67143f202f0426d76d7 (patch)
tree12216fc69a7ef7dea0efb86a14b1c0815aa5f655 /fs/gfs2
parent37975f1503715c51c1a2484b8aba2700a23e6b56 (diff)
downloadlinux-0e27c18c30f6850ecd0fb67143f202f0426d76d7.tar.xz
GFS2: Set of distributed preferences for rgrps
This patch tries to use the journal numbers to evenly distribute which node prefers which resource group for block allocations. This is to help performance. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2')
-rw-r--r--fs/gfs2/incore.h1
-rw-r--r--fs/gfs2/rgrp.c66
2 files changed, 62 insertions, 5 deletions
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 39e7e9959b74..1b899187be5a 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -97,6 +97,7 @@ struct gfs2_rgrpd {
#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 */
+#define GFS2_RDF_PREFERRED 0x80000000 /* This rgrp is preferred */
#define GFS2_RDF_MASK 0xf0000000 /* mask for internal flags */
spinlock_t rd_rsspin; /* protects reservation related vars */
struct rb_root rd_rstree; /* multi-block reservation tree */
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 7474c413ffd1..f4e4a0c5babe 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -936,7 +936,7 @@ static int read_rindex_entry(struct gfs2_inode *ip)
rgd->rd_gl->gl_vm.start = rgd->rd_addr * bsize;
rgd->rd_gl->gl_vm.end = rgd->rd_gl->gl_vm.start + (rgd->rd_length * bsize) - 1;
rgd->rd_rgl = (struct gfs2_rgrp_lvb *)rgd->rd_gl->gl_lksb.sb_lvbptr;
- rgd->rd_flags &= ~GFS2_RDF_UPTODATE;
+ rgd->rd_flags &= ~(GFS2_RDF_UPTODATE | GFS2_RDF_PREFERRED);
if (rgd->rd_data > sdp->sd_max_rg_data)
sdp->sd_max_rg_data = rgd->rd_data;
spin_lock(&sdp->sd_rindex_spin);
@@ -955,6 +955,36 @@ fail:
}
/**
+ * set_rgrp_preferences - Run all the rgrps, selecting some we prefer to use
+ * @sdp: the GFS2 superblock
+ *
+ * The purpose of this function is to select a subset of the resource groups
+ * and mark them as PREFERRED. We do it in such a way that each node prefers
+ * to use a unique set of rgrps to minimize glock contention.
+ */
+static void set_rgrp_preferences(struct gfs2_sbd *sdp)
+{
+ struct gfs2_rgrpd *rgd, *first;
+ int i;
+
+ /* Skip an initial number of rgrps, based on this node's journal ID.
+ That should start each node out on its own set. */
+ rgd = gfs2_rgrpd_get_first(sdp);
+ for (i = 0; i < sdp->sd_lockstruct.ls_jid; i++)
+ rgd = gfs2_rgrpd_get_next(rgd);
+ first = rgd;
+
+ do {
+ rgd->rd_flags |= GFS2_RDF_PREFERRED;
+ for (i = 0; i < sdp->sd_journals; i++) {
+ rgd = gfs2_rgrpd_get_next(rgd);
+ if (rgd == first)
+ break;
+ }
+ } while (rgd != first);
+}
+
+/**
* gfs2_ri_update - Pull in a new resource index from the disk
* @ip: pointer to the rindex inode
*
@@ -973,6 +1003,8 @@ static int gfs2_ri_update(struct gfs2_inode *ip)
if (error < 0)
return error;
+ set_rgrp_preferences(sdp);
+
sdp->sd_rindex_uptodate = 1;
return 0;
}
@@ -1891,6 +1923,25 @@ static bool gfs2_select_rgrp(struct gfs2_rgrpd **pos, const struct gfs2_rgrpd *b
}
/**
+ * fast_to_acquire - determine if a resource group will be fast to acquire
+ *
+ * If this is one of our preferred rgrps, it should be quicker to acquire,
+ * because we tried to set ourselves up as dlm lock master.
+ */
+static inline int fast_to_acquire(struct gfs2_rgrpd *rgd)
+{
+ struct gfs2_glock *gl = rgd->rd_gl;
+
+ if (gl->gl_state != LM_ST_UNLOCKED && list_empty(&gl->gl_holders) &&
+ !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
+ !test_bit(GLF_DEMOTE, &gl->gl_flags))
+ return 1;
+ if (rgd->rd_flags & GFS2_RDF_PREFERRED)
+ return 1;
+ return 0;
+}
+
+/**
* gfs2_inplace_reserve - Reserve space in the filesystem
* @ip: the inode to reserve space for
* @ap: the allocation parameters
@@ -1932,10 +1983,15 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, const struct gfs2_alloc_parms *a
rg_locked = 0;
if (skip && skip--)
goto next_rgrp;
- if (!gfs2_rs_active(rs) && (loops < 2) &&
- gfs2_rgrp_used_recently(rs, 1000) &&
- gfs2_rgrp_congested(rs->rs_rbm.rgd, loops))
- goto next_rgrp;
+ if (!gfs2_rs_active(rs)) {
+ if (loops == 0 &&
+ !fast_to_acquire(rs->rs_rbm.rgd))
+ goto next_rgrp;
+ if ((loops < 2) &&
+ gfs2_rgrp_used_recently(rs, 1000) &&
+ gfs2_rgrp_congested(rs->rs_rbm.rgd, loops))
+ goto next_rgrp;
+ }
error = gfs2_glock_nq_init(rs->rs_rbm.rgd->rd_gl,
LM_ST_EXCLUSIVE, flags,
&rs->rs_rgd_gh);