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Date: Fri, 11 Jul 2008 11:11:17 +0100
From: swhiteho@...hat.com
To: linux-kernel@...r.kernel.org, cluster-devel@...hat.com
Cc: Steven Whitehouse <swhiteho@...hat.com>
Subject: [PATCH 16/18] [GFS2] Replace rgrp "recent list" with mru list
From: Steven Whitehouse <swhiteho@...hat.com>
This patch removes the "recent list" which is used during allocation
and replaces it with the (already existing) mru list used during
deletion. The "recent list" was not a true mru list leading to a number
of inefficiencies including a "next" function which made scanning the
list an order N^2 operation wrt to the number of list elements.
This should increase allocation performance with large numbers of rgrps.
Its also a useful preparation and cleanup before some further changes
which are planned in this area.
Signed-off-by: Steven Whitehouse <swhiteho@...hat.com>
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 4b734c6..4ab3c3a 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -77,7 +77,6 @@ struct gfs2_rgrp_host {
struct gfs2_rgrpd {
struct list_head rd_list; /* Link with superblock */
struct list_head rd_list_mru;
- struct list_head rd_recent; /* Recently used rgrps */
struct gfs2_glock *rd_gl; /* Glock for this rgrp */
u64 rd_addr; /* grp block disk address */
u64 rd_data0; /* first data location */
@@ -529,7 +528,6 @@ struct gfs2_sbd {
struct mutex sd_rindex_mutex;
struct list_head sd_rindex_list;
struct list_head sd_rindex_mru_list;
- struct list_head sd_rindex_recent_list;
struct gfs2_rgrpd *sd_rindex_forward;
unsigned int sd_rgrps;
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 6ba69dd..b4d1d64 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -64,7 +64,6 @@ static struct gfs2_sbd *init_sbd(struct super_block *sb)
mutex_init(&sdp->sd_rindex_mutex);
INIT_LIST_HEAD(&sdp->sd_rindex_list);
INIT_LIST_HEAD(&sdp->sd_rindex_mru_list);
- INIT_LIST_HEAD(&sdp->sd_rindex_recent_list);
INIT_LIST_HEAD(&sdp->sd_jindex_list);
spin_lock_init(&sdp->sd_jindex_spin);
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 3401628..2d90fb2 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -371,11 +371,6 @@ static void clear_rgrpdi(struct gfs2_sbd *sdp)
spin_lock(&sdp->sd_rindex_spin);
sdp->sd_rindex_forward = NULL;
- head = &sdp->sd_rindex_recent_list;
- while (!list_empty(head)) {
- rgd = list_entry(head->next, struct gfs2_rgrpd, rd_recent);
- list_del(&rgd->rd_recent);
- }
spin_unlock(&sdp->sd_rindex_spin);
head = &sdp->sd_rindex_list;
@@ -945,107 +940,30 @@ static struct inode *try_rgrp_unlink(struct gfs2_rgrpd *rgd, u64 *last_unlinked)
}
/**
- * recent_rgrp_first - get first RG from "recent" list
- * @sdp: The GFS2 superblock
- * @rglast: address of the rgrp used last
- *
- * Returns: The first rgrp in the recent list
- */
-
-static struct gfs2_rgrpd *recent_rgrp_first(struct gfs2_sbd *sdp,
- u64 rglast)
-{
- struct gfs2_rgrpd *rgd;
-
- spin_lock(&sdp->sd_rindex_spin);
-
- if (rglast) {
- list_for_each_entry(rgd, &sdp->sd_rindex_recent_list, rd_recent) {
- if (rgrp_contains_block(rgd, rglast))
- goto out;
- }
- }
- rgd = NULL;
- if (!list_empty(&sdp->sd_rindex_recent_list))
- rgd = list_entry(sdp->sd_rindex_recent_list.next,
- struct gfs2_rgrpd, rd_recent);
-out:
- spin_unlock(&sdp->sd_rindex_spin);
- return rgd;
-}
-
-/**
* recent_rgrp_next - get next RG from "recent" list
* @cur_rgd: current rgrp
- * @remove:
*
* Returns: The next rgrp in the recent list
*/
-static struct gfs2_rgrpd *recent_rgrp_next(struct gfs2_rgrpd *cur_rgd,
- int remove)
+static struct gfs2_rgrpd *recent_rgrp_next(struct gfs2_rgrpd *cur_rgd)
{
struct gfs2_sbd *sdp = cur_rgd->rd_sbd;
struct list_head *head;
struct gfs2_rgrpd *rgd;
spin_lock(&sdp->sd_rindex_spin);
-
- head = &sdp->sd_rindex_recent_list;
-
- list_for_each_entry(rgd, head, rd_recent) {
- if (rgd == cur_rgd) {
- if (cur_rgd->rd_recent.next != head)
- rgd = list_entry(cur_rgd->rd_recent.next,
- struct gfs2_rgrpd, rd_recent);
- else
- rgd = NULL;
-
- if (remove)
- list_del(&cur_rgd->rd_recent);
-
- goto out;
- }
+ head = &sdp->sd_rindex_mru_list;
+ if (unlikely(cur_rgd->rd_list_mru.next == head)) {
+ spin_unlock(&sdp->sd_rindex_spin);
+ return NULL;
}
-
- rgd = NULL;
- if (!list_empty(head))
- rgd = list_entry(head->next, struct gfs2_rgrpd, rd_recent);
-
-out:
+ rgd = list_entry(cur_rgd->rd_list_mru.next, struct gfs2_rgrpd, rd_list_mru);
spin_unlock(&sdp->sd_rindex_spin);
return rgd;
}
/**
- * recent_rgrp_add - add an RG to tail of "recent" list
- * @new_rgd: The rgrp to add
- *
- */
-
-static void recent_rgrp_add(struct gfs2_rgrpd *new_rgd)
-{
- struct gfs2_sbd *sdp = new_rgd->rd_sbd;
- struct gfs2_rgrpd *rgd;
- unsigned int count = 0;
- unsigned int max = sdp->sd_rgrps / gfs2_jindex_size(sdp);
-
- spin_lock(&sdp->sd_rindex_spin);
-
- list_for_each_entry(rgd, &sdp->sd_rindex_recent_list, rd_recent) {
- if (rgd == new_rgd)
- goto out;
-
- if (++count >= max)
- goto out;
- }
- list_add_tail(&new_rgd->rd_recent, &sdp->sd_rindex_recent_list);
-
-out:
- spin_unlock(&sdp->sd_rindex_spin);
-}
-
-/**
* forward_rgrp_get - get an rgrp to try next from full list
* @sdp: The GFS2 superblock
*
@@ -1112,9 +1030,7 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
int loops = 0;
int error, rg_locked;
- /* Try recently successful rgrps */
-
- rgd = recent_rgrp_first(sdp, ip->i_goal);
+ rgd = gfs2_blk2rgrpd(sdp, ip->i_goal);
while (rgd) {
rg_locked = 0;
@@ -1136,11 +1052,9 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
gfs2_glock_dq_uninit(&al->al_rgd_gh);
if (inode)
return inode;
- rgd = recent_rgrp_next(rgd, 1);
- break;
-
+ /* fall through */
case GLR_TRYFAILED:
- rgd = recent_rgrp_next(rgd, 0);
+ rgd = recent_rgrp_next(rgd);
break;
default:
@@ -1199,7 +1113,9 @@ static struct inode *get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
out:
if (begin) {
- recent_rgrp_add(rgd);
+ spin_lock(&sdp->sd_rindex_spin);
+ list_move(&rgd->rd_list_mru, &sdp->sd_rindex_mru_list);
+ spin_unlock(&sdp->sd_rindex_spin);
rgd = gfs2_rgrpd_get_next(rgd);
if (!rgd)
rgd = gfs2_rgrpd_get_first(sdp);
--
1.5.1.2
--
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