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authorBob Peterson <rpeterso@redhat.com>2019-04-05 04:41:38 +0100
committerAndreas Gruenbacher <agruenba@redhat.com>2019-05-07 23:39:14 +0200
commit73118ca8baf78dddd1f9c8ac67c1d80b47d9830e (patch)
tree72c0d2a327c8bace37ce5984f39d971ab5768594 /fs/gfs2/lops.c
parent9287c6452d2b1f24ea8e84bd3cf6f3c6f267f712 (diff)
gfs2: Replace gl_revokes with a GLF flag
The gl_revokes value determines how many outstanding revokes a glock has on the superblock revokes list; this is used to avoid unnecessary log flushes. However, gl_revokes is only ever tested for being zero, and it's only decremented in revoke_lo_after_commit, which removes all revokes from the list, so we know that the gl_revoke values of all the glocks on the list will reach zero. Therefore, we can replace gl_revokes with a bit flag. This saves an atomic counter in struct gfs2_glock. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Diffstat (limited to 'fs/gfs2/lops.c')
-rw-r--r--fs/gfs2/lops.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index b4f0a6a3ba59..2fd61853ba63 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -662,19 +662,34 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
static void revoke_lo_after_commit(struct gfs2_sbd *sdp, struct gfs2_trans *tr)
{
struct list_head *head = &sdp->sd_log_le_revoke;
- struct gfs2_bufdata *bd;
- struct gfs2_glock *gl;
+ struct gfs2_bufdata *bd, *tmp;
- while (!list_empty(head)) {
- bd = list_entry(head->next, struct gfs2_bufdata, bd_list);
- list_del_init(&bd->bd_list);
- gl = bd->bd_gl;
- if (atomic_dec_return(&gl->gl_revokes) == 0) {
- clear_bit(GLF_LFLUSH, &gl->gl_flags);
- gfs2_glock_queue_put(gl);
+ /*
+ * Glocks can be referenced repeatedly on the revoke list, but the list
+ * only holds one reference. All glocks on the list will have the
+ * GLF_REVOKES flag set initially.
+ */
+
+ list_for_each_entry_safe(bd, tmp, head, bd_list) {
+ struct gfs2_glock *gl = bd->bd_gl;
+
+ if (test_bit(GLF_REVOKES, &gl->gl_flags)) {
+ /* Keep each glock on the list exactly once. */
+ clear_bit(GLF_REVOKES, &gl->gl_flags);
+ continue;
}
+ list_del(&bd->bd_list);
+ kmem_cache_free(gfs2_bufdata_cachep, bd);
+ }
+ list_for_each_entry_safe(bd, tmp, head, bd_list) {
+ struct gfs2_glock *gl = bd->bd_gl;
+
+ list_del(&bd->bd_list);
kmem_cache_free(gfs2_bufdata_cachep, bd);
+ clear_bit(GLF_LFLUSH, &gl->gl_flags);
+ gfs2_glock_queue_put(gl);
}
+ /* the list is empty now */
}
static void revoke_lo_before_scan(struct gfs2_jdesc *jd,