LU-1282 lprocfs: fix multi-thread contention glitch

[fs/lustre-release.git] / lustre / lvfs / lvfs_lib.c

diff --git a/lustre/lvfs/lvfs_lib.c b/lustre/lvfs/lvfs_lib.c
index ffdfadf..075c1d0 100644 (file)
--- a/lustre/lvfs/lvfs_lib.c
+++ b/lustre/lvfs/lvfs_lib.c
@@ -148,8 +148,9 @@ EXPORT_SYMBOL(lprocfs_counter_sub);
 
 int lprocfs_stats_alloc_one(struct lprocfs_stats *stats, unsigned int idx)
 {
-       unsigned int percpusize;
-       int          rc = -ENOMEM;
+       unsigned int    percpusize;
+       int             rc      = -ENOMEM;
+       unsigned long   flags   = 0;
 
        /* the 1st percpu entry was statically allocated in
         * lprocfs_alloc_stats() */
@@ -162,8 +163,20 @@ int lprocfs_stats_alloc_one(struct lprocfs_stats *stats, unsigned int idx)
        OBD_ALLOC_GFP(stats->ls_percpu[idx], percpusize, CFS_ALLOC_ATOMIC);
        if (stats->ls_percpu[idx] != NULL) {
                rc = 0;
-               if (unlikely(stats->ls_biggest_alloc_num <= idx))
-                       stats->ls_biggest_alloc_num = idx + 1;
+               if (unlikely(stats->ls_biggest_alloc_num <= idx)) {
+                       if (stats->ls_flags & LPROCFS_STATS_FLAG_IRQ_SAFE)
+                               cfs_spin_lock_irqsave(&stats->ls_lock, flags);
+                       else
+                               cfs_spin_lock(&stats->ls_lock);
+                       if (stats->ls_biggest_alloc_num <= idx)
+                               stats->ls_biggest_alloc_num = idx + 1;
+                       if (stats->ls_flags & LPROCFS_STATS_FLAG_IRQ_SAFE) {
+                               cfs_spin_unlock_irqrestore(&stats->ls_lock,
+                                                          flags);
+                       } else {
+                               cfs_spin_unlock(&stats->ls_lock);
+                       }
+               }
 
                /* initialize the ls_percpu[idx] by copying the 0th template
                 * entry */