[Cluster-devel] [GFS2 PATCH] GFS2: Don't add all glocks to the lru

[Bob Peterson <rpeterso@redhat.com>]

Hi,

Regarding my previously posted patch:
I decided it makes more sense not to single out rgrp glocks for
exclusion from the lru list. It makes sense to also exclude the
transaction glock, and "non-disk" glocks off the lru list as well.
Therefore, I changed this to a generic "glops" flag so we could
specify them on an individual basis.

Patch description:

The glocks used for resource groups often come and go hundreds of
thousands of time per second. Adding them to the lru list just
adds unnecessary contention for the lru_lock spin_lock, especially
considering we're almost certainly going to re-use the glock and
take it back off the lru microseconds later. We never want the
glock shrinker to cull them anyway. This patch adds a new bit in
the glops that determines which glock types get put onto the lru
list and which ones don't.

Regards,

Bob Peterson

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 0fa8062..a38e38f 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1076,7 +1076,8 @@ void gfs2_glock_dq(struct gfs2_holder *gh)
 		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
 			fast_path = 1;
 	}
-	if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
+	if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
+	    (glops->go_flags & GLOF_LRU))
 		gfs2_glock_add_to_lru(gl);
 
 	trace_gfs2_glock_queue(gh, 0);
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index fe91951..1249b2b 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -561,7 +561,7 @@ const struct gfs2_glock_operations gfs2_inode_glops = {
 	.go_lock = inode_go_lock,
 	.go_dump = inode_go_dump,
 	.go_type = LM_TYPE_INODE,
-	.go_flags = GLOF_ASPACE,
+	.go_flags = GLOF_ASPACE | GLOF_LRU,
 };
 
 const struct gfs2_glock_operations gfs2_rgrp_glops = {
@@ -584,10 +584,12 @@ const struct gfs2_glock_operations gfs2_freeze_glops = {
 const struct gfs2_glock_operations gfs2_iopen_glops = {
 	.go_type = LM_TYPE_IOPEN,
 	.go_callback = iopen_go_callback,
+	.go_flags = GLOF_LRU,
 };
 
 const struct gfs2_glock_operations gfs2_flock_glops = {
 	.go_type = LM_TYPE_FLOCK,
+	.go_flags = GLOF_LRU,
 };
 
 const struct gfs2_glock_operations gfs2_nondisk_glops = {
@@ -596,7 +598,7 @@ const struct gfs2_glock_operations gfs2_nondisk_glops = {
 
 const struct gfs2_glock_operations gfs2_quota_glops = {
 	.go_type = LM_TYPE_QUOTA,
-	.go_flags = GLOF_LVB,
+	.go_flags = GLOF_LVB | GLOF_LRU,
 };
 
 const struct gfs2_glock_operations gfs2_journal_glops = {
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 304a223..a1ec7c2 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -225,6 +225,7 @@ struct gfs2_glock_operations {
 	const unsigned long go_flags;
 #define GLOF_ASPACE 1
 #define GLOF_LVB    2
+#define GLOF_LRU    4
 };
 
 enum {