Keep the current value of the updated log tail in the super block as
sb_log_flush_tail instead of computing it on the fly. This avoids
unnecessary sd_ail_lock taking and cleans up the code.
Signed-off-by: Andreas Gruenbacher <agrue...@redhat.com>
---
fs/gfs2/incore.h | 5 ++--
fs/gfs2/log.c | 72 +++++++++++++++++++++++++-----------------------
fs/gfs2/log.h | 4 ++-
3 files changed, 44 insertions(+), 37 deletions(-)
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index c155fd39bc98..fdf4d942bb1d 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -837,8 +837,6 @@ struct gfs2_sbd {
wait_queue_head_t sd_logd_waitq;
u64 sd_log_sequence;
- unsigned int sd_log_head;
- unsigned int sd_log_tail;
int sd_log_idle;
struct rw_semaphore sd_log_flush_lock;
@@ -848,6 +846,9 @@ struct gfs2_sbd {
int sd_log_error; /* First log error */
wait_queue_head_t sd_withdraw_wait;
+ unsigned int sd_log_tail;
+ unsigned int sd_log_flush_tail;
+ unsigned int sd_log_head;
unsigned int sd_log_flush_head;
spinlock_t sd_ail_lock;
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 24a292065b9c..1ca5f2c468d5 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -242,6 +242,28 @@ static void gfs2_ail1_start(struct gfs2_sbd *sdp)
return gfs2_ail1_flush(sdp, &wbc);
}
+static void gfs2_log_update_flush_tail(struct gfs2_sbd *sdp)
+{
+ unsigned int new_flush_tail = sdp->sd_log_head;
+ struct gfs2_trans *tr;
+
+ if (!list_empty(&sdp->sd_ail1_list)) {
+ tr = list_last_entry(&sdp->sd_ail1_list,
+ struct gfs2_trans, tr_list);
+ new_flush_tail = tr->tr_first;
+ }
+ sdp->sd_log_flush_tail = new_flush_tail;
+}
+
+static void gfs2_log_update_head(struct gfs2_sbd *sdp)
+{
+ unsigned int new_head = sdp->sd_log_flush_head;
+
+ if (sdp->sd_log_flush_tail == sdp->sd_log_head)
+ sdp->sd_log_flush_tail = new_head;
+ sdp->sd_log_head = new_head;
+}
+
/**
* gfs2_ail1_empty_one - Check whether or not a trans in the AIL has been
synced
* @sdp: the filesystem
@@ -317,6 +339,7 @@ static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int
max_revokes)
else
oldest_tr = 0;
}
+ gfs2_log_update_flush_tail(sdp);
ret = list_empty(&sdp->sd_ail1_list);
spin_unlock(&sdp->sd_ail_lock);
@@ -544,30 +567,14 @@ static unsigned int calc_reserved(struct gfs2_sbd *sdp)
return reserved;
}
-static unsigned int current_tail(struct gfs2_sbd *sdp)
-{
- struct gfs2_trans *tr;
- unsigned int tail;
-
- spin_lock(&sdp->sd_ail_lock);
-
- if (list_empty(&sdp->sd_ail1_list)) {
- tail = sdp->sd_log_head;
- } else {
- tr = list_last_entry(&sdp->sd_ail1_list, struct gfs2_trans,
- tr_list);
- tail = tr->tr_first;
- }
-
- spin_unlock(&sdp->sd_ail_lock);
-
- return tail;
-}
-
-static void log_pull_tail(struct gfs2_sbd *sdp, unsigned int new_tail)
+static void log_pull_tail(struct gfs2_sbd *sdp)
{
- unsigned int dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
+ unsigned int new_tail = sdp->sd_log_flush_tail;
+ unsigned int dist;
+ if (new_tail == sdp->sd_log_tail)
+ return;
+ dist = log_distance(sdp, new_tail, sdp->sd_log_tail);
ail2_empty(sdp, new_tail);
gfs2_log_release(sdp, dist);
sdp->sd_log_tail = new_tail;
@@ -822,26 +829,23 @@ void gfs2_write_log_header(struct gfs2_sbd *sdp, struct
gfs2_jdesc *jd,
static void log_write_header(struct gfs2_sbd *sdp, u32 flags)
{
- unsigned int tail;
int op_flags = REQ_PREFLUSH | REQ_FUA | REQ_META | REQ_SYNC;
enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
gfs2_assert_withdraw(sdp, (state != SFS_FROZEN));
- tail = current_tail(sdp);
if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) {
gfs2_ordered_wait(sdp);
log_flush_wait(sdp);
op_flags = REQ_SYNC | REQ_META | REQ_PRIO;
}
- sdp->sd_log_idle = (tail == sdp->sd_log_flush_head);
- gfs2_write_log_header(sdp, sdp->sd_jdesc, sdp->sd_log_sequence++, tail,
- sdp->sd_log_flush_head, flags, op_flags);
+ sdp->sd_log_idle = (sdp->sd_log_flush_tail == sdp->sd_log_flush_head);
+ gfs2_write_log_header(sdp, sdp->sd_jdesc, sdp->sd_log_sequence++,
+ sdp->sd_log_flush_tail, sdp->sd_log_flush_head,
+ flags, op_flags);
gfs2_log_incr_head(sdp);
log_flush_wait(sdp);
-
- if (sdp->sd_log_tail != tail)
- log_pull_tail(sdp, tail);
+ log_pull_tail(sdp);
}
/**
@@ -991,7 +995,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock
*gl, u32 flags)
if (sdp->sd_log_head != sdp->sd_log_flush_head) {
log_flush_wait(sdp);
log_write_header(sdp, flags);
- } else if (sdp->sd_log_tail != current_tail(sdp) && !sdp->sd_log_idle) {
+ } else if (sdp->sd_log_tail != sdp->sd_log_flush_tail &&
!sdp->sd_log_idle) {
atomic_dec(&sdp->sd_log_blks_free); /* Adjust for unreserved
buffer */
trace_gfs2_log_blocks(sdp, -1);
log_write_header(sdp, flags);
@@ -1001,7 +1005,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct
gfs2_glock *gl, u32 flags)
lops_after_commit(sdp, tr);
gfs2_log_lock(sdp);
- sdp->sd_log_head = sdp->sd_log_flush_head;
+ gfs2_log_update_head(sdp);
sdp->sd_log_blks_reserved = 0;
sdp->sd_log_committed_revoke = 0;
@@ -1021,7 +1025,7 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct
gfs2_glock *gl, u32 flags)
atomic_dec(&sdp->sd_log_blks_free); /* Adjust for
unreserved buffer */
trace_gfs2_log_blocks(sdp, -1);
log_write_header(sdp, flags);
- sdp->sd_log_head = sdp->sd_log_flush_head;
+ gfs2_log_update_head(sdp);
}
if (flags & (GFS2_LOG_HEAD_FLUSH_SHUTDOWN |
GFS2_LOG_HEAD_FLUSH_FREEZE))
@@ -1155,7 +1159,7 @@ static void gfs2_log_shutdown(struct gfs2_sbd *sdp)
gfs2_assert_warn(sdp, sdp->sd_log_head == sdp->sd_log_tail);
gfs2_assert_warn(sdp, list_empty(&sdp->sd_ail2_list));
- sdp->sd_log_head = sdp->sd_log_flush_head;
+ gfs2_log_update_head(sdp);
sdp->sd_log_tail = sdp->sd_log_head;
}
diff --git a/fs/gfs2/log.h b/fs/gfs2/log.h
index cbc097ca9244..b36a3539f352 100644
--- a/fs/gfs2/log.h
+++ b/fs/gfs2/log.h
@@ -43,7 +43,9 @@ static inline void gfs2_log_pointers_init(struct gfs2_sbd
*sdp,
if (++value == sdp->sd_jdesc->jd_blocks) {
value = 0;
}
- sdp->sd_log_head = sdp->sd_log_tail = value;
+ sdp->sd_log_tail = value;
+ sdp->sd_log_flush_tail = value;
+ sdp->sd_log_head = value;
}
static inline void gfs2_ordered_add_inode(struct gfs2_inode *ip)
--
2.26.2
