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gfs2: Get rid of current_tail()

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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 <agruenba@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2020-12-19 07:15:17 +01:00
parent 297de3180d
commit 5cb738b5fb
3 changed files with 44 additions and 37 deletions
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5
fs/gfs2/incore.h
View file

@ -838,8 +838,6 @@ 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;
@ -849,6 +847,9 @@ 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;

72
fs/gfs2/log.c
View file

@ -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)
static void log_pull_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)
{
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))
@ -1156,7 +1160,7 @@ 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;
}

4
fs/gfs2/log.h
View file

@ -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)