GFS2: Reduce contention on gfs2_log_lock
This patch modifies functions gfs2_trans_add_meta and _data so that
they check whether the buffer_head is already in a transaction,
and if so, avoid taking the gfs2_log_lock.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
index 483c5a7..affef3c 100644
--- a/fs/gfs2/trans.c
+++ b/fs/gfs2/trans.c
@@ -170,6 +170,10 @@
}
lock_buffer(bh);
+ if (buffer_pinned(bh)) {
+ set_bit(TR_TOUCHED, &tr->tr_flags);
+ goto out;
+ }
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd == NULL) {
@@ -192,6 +196,7 @@
list_add_tail(&bd->bd_list, &tr->tr_databuf);
}
gfs2_log_unlock(sdp);
+out:
unlock_buffer(bh);
}
@@ -201,10 +206,14 @@
struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
struct gfs2_bufdata *bd;
struct gfs2_meta_header *mh;
- struct gfs2_trans *tr;
+ struct gfs2_trans *tr = current->journal_info;
enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
lock_buffer(bh);
+ if (buffer_pinned(bh)) {
+ set_bit(TR_TOUCHED, &tr->tr_flags);
+ goto out;
+ }
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd == NULL) {
@@ -220,7 +229,6 @@
gfs2_log_lock(sdp);
}
gfs2_assert(sdp, bd->bd_gl == gl);
- tr = current->journal_info;
set_bit(TR_TOUCHED, &tr->tr_flags);
if (!list_empty(&bd->bd_list))
goto out_unlock;
@@ -243,6 +251,7 @@
tr->tr_num_buf_new++;
out_unlock:
gfs2_log_unlock(sdp);
+out:
unlock_buffer(bh);
}