[GFS2] Speed up lock_dlm's locking (move sprintf)

The following patch speeds up lock_dlm's locking by moving the sprintf
out from the lock acquisition path and into the lock creation path. This
reduces the amount of CPU time used in acquiring locks by a fair amount.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: David Teigland <teigland@redhat.com>

2 files changed, 5 insertions, 6 deletions

diff --git a/fs/gfs2/locking/dlm/lock.c b/fs/gfs2/locking/dlm/lock.c
index b167addf9fd1..f9c8bda289a8 100644
--- a/fs/gfs2/locking/dlm/lock.c
+++ b/fs/gfs2/locking/dlm/lock.c
@@ -151,7 +151,7 @@ static inline unsigned int make_flags(struct gdlm_lock *lp,
 
 /* make_strname - convert GFS lock numbers to a string */
 
-static inline void make_strname(struct lm_lockname *lockname,
+static inline void make_strname(const struct lm_lockname *lockname,
                                 struct gdlm_strname *str)
 {
         sprintf(str->name, "%8x%16llx", lockname->ln_type,
@@ -169,6 +169,7 @@ static int gdlm_create_lp(struct gdlm_ls *ls, struct lm_lockname *name,
                 return -ENOMEM;
 
         lp->lockname = *name;
+        make_strname(name, &lp->strname);
         lp->ls = ls;
         lp->cur = DLM_LOCK_IV;
         lp->lvb = NULL;
@@ -227,7 +228,6 @@ void gdlm_put_lock(void *lock)
 unsigned int gdlm_do_lock(struct gdlm_lock *lp)
 {
         struct gdlm_ls *ls = lp->ls;
-        struct gdlm_strname str;
         int error, bast = 1;
 
         /*
@@ -249,8 +249,6 @@ unsigned int gdlm_do_lock(struct gdlm_lock *lp)
         if (test_bit(LFL_NOBAST, &lp->flags))
                 bast = 0;
 
-        make_strname(&lp->lockname, &str);
-
         set_bit(LFL_ACTIVE, &lp->flags);
 
         log_debug("lk %x,%llx id %x %d,%d %x", lp->lockname.ln_type,
@@ -258,8 +256,8 @@ unsigned int gdlm_do_lock(struct gdlm_lock *lp)
                   lp->cur, lp->req, lp->lkf);
 
         error = dlm_lock(ls->dlm_lockspace, lp->req, &lp->lksb, lp->lkf,
-                         str.name, str.namelen, 0, gdlm_ast, lp,
-                         bast ? gdlm_bast : NULL);
+                         lp->strname.name, lp->strname.namelen, 0, gdlm_ast,
+                         lp, bast ? gdlm_bast : NULL);
 
         if ((error == -EAGAIN) && (lp->lkf & DLM_LKF_NOQUEUE)) {
                 lp->lksb.sb_status = -EAGAIN;
diff --git a/fs/gfs2/locking/dlm/lock_dlm.h b/fs/gfs2/locking/dlm/lock_dlm.h
index a87c7bf3c568..6888bd49c31b 100644
--- a/fs/gfs2/locking/dlm/lock_dlm.h
+++ b/fs/gfs2/locking/dlm/lock_dlm.h
@@ -106,6 +106,7 @@ enum {
 struct gdlm_lock {
         struct gdlm_ls          *ls;
         struct lm_lockname      lockname;
+        struct gdlm_strname     strname;
         char                    *lvb;
         struct dlm_lksb         lksb;