[PATCH 6/7] xfs: user per-cpu stats for the total dquot numbers

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

Switch the total number of dquots counter over to use the per-cpu stats
implementation, and reintroduce the number of unused dquots counter
dropped earlier in the series.

Btw, I wonder if we should simply add these counters to /proc/fs/xfs/xqmstat
instead of keeping the odd format and mostly superflous /proc/fs/xfs/xqm
around.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

---
 fs/xfs/xfs_dquot.c    |    7 ++++---
 fs/xfs/xfs_qm.c       |    3 ++-
 fs/xfs/xfs_qm.h       |    1 -
 fs/xfs/xfs_qm_stats.c |    4 ++--
 fs/xfs/xfs_qm_stats.h |    5 +++++
 5 files changed, 13 insertions(+), 7 deletions(-)

Index: xfs/fs/xfs/xfs_qm_stats.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_stats.c      2012-02-01 12:30:02.000000000 +0100
+++ xfs/fs/xfs/xfs_qm_stats.c   2012-02-01 12:30:48.359059367 +0100
@@ -52,9 +52,9 @@ static int xqm_proc_show(struct seq_file
        /* maximum; incore; ratio free to inuse; freelist */
        seq_printf(m, "%d\t%d\t%d\t%u\n",
                        0,
-                       xfs_Gqm? atomic_read(&xfs_Gqm->qm_totaldquots) : 0,
+                       xqmstats_sum(XQMSTAT_END_XQMSTAT),
                        0,
-                       0);
+                       xqmstats_sum(XQMSTAT_END_XQMSTAT + 1));
        return 0;
 }
 
Index: xfs/fs/xfs/xfs_qm_stats.h
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_stats.h      2012-02-01 12:30:02.000000000 +0100
+++ xfs/fs/xfs/xfs_qm_stats.h   2012-02-01 12:30:48.362392682 +0100
@@ -33,6 +33,9 @@ struct xqmstats {
        __uint32_t              xs_qm_dqshake_reclaims;
        __uint32_t              xs_qm_dqinact_reclaims;
 #define XQMSTAT_END_XQMSTAT    8
+       __uint32_t              xs_qm_dquots;
+       __uint32_t              xs_qm_dquots_unused;
+#define XQMSTAT_END_XQM                (XQMSTAT_END_XQMSTAT + 4)
 };
 
 DECLARE_PER_CPU(struct xqmstats, xqmstats);
@@ -42,6 +45,7 @@ DECLARE_PER_CPU(struct xqmstats, xqmstat
  * wrong CPU's stat for now (also aggregated before reporting).
  */
 # define XQM_STATS_INC(v)      (per_cpu(xqmstats, current_cpu()).v++)
+# define XQM_STATS_DEC(v)      (per_cpu(xqmstats, current_cpu()).v--)
 
 extern void xfs_qm_init_procfs(void);
 extern void xfs_qm_cleanup_procfs(void);
@@ -49,6 +53,7 @@ extern void xfs_qm_cleanup_procfs(void);
 #else
 
 # define XQM_STATS_INC(v)      do { } while (0)
+# define XQM_STATS_DEC(v)      do { } while (0)
 
 static inline void xfs_qm_init_procfs(void) { };
 static inline void xfs_qm_cleanup_procfs(void) { };
Index: xfs/fs/xfs/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.c 2012-02-01 12:30:02.000000000 +0100
+++ xfs/fs/xfs/xfs_dquot.c      2012-02-01 12:30:48.362392682 +0100
@@ -72,8 +72,7 @@ xfs_qm_dqdestroy(
 
        mutex_destroy(&dqp->q_qlock);
        kmem_zone_free(xfs_Gqm->qm_dqzone, dqp);
-
-       atomic_dec(&xfs_Gqm->qm_totaldquots);
+       XQM_STATS_DEC(xs_qm_dquots);
 }
 
 /*
@@ -515,7 +514,7 @@ xfs_qm_dqread(
        if (!(type & XFS_DQ_USER))
                lockdep_set_class(&dqp->q_qlock, &xfs_dquot_other_class);
 
-       atomic_inc(&xfs_Gqm->qm_totaldquots);
+       XQM_STATS_INC(xs_qm_dquots);
 
        trace_xfs_dqread(dqp);
 
@@ -786,6 +785,7 @@ recurse:
                list_add_tail(&dqp->q_lru,
                              &dqp->q_mount->m_quotainfo->qi_lru_list);
                dqp->q_mount->m_quotainfo->qi_lru_count++;
+               XQM_STATS_INC(xs_qm_dquots_unused);
        }
        mutex_unlock(&dqp->q_mount->m_quotainfo->qi_lru_lock);
 
@@ -1104,6 +1104,7 @@ xfs_qm_dqpurge(
        qi->qi_lru_count--;
        mutex_unlock(&qi->qi_lru_lock);
 
+       XQM_STATS_DEC(xs_qm_dquots_unused);
        xfs_qm_dqdestroy(dqp);
        return 0;
 }
Index: xfs/fs/xfs/xfs_qm.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.c    2012-02-01 12:30:26.000000000 +0100
+++ xfs/fs/xfs/xfs_qm.c 2012-02-01 12:31:11.988931351 +0100
@@ -89,7 +89,6 @@ xfs_Gqm_init(void)
        } else
                xqm->qm_dqtrxzone = qm_dqtrxzone;
 
-       atomic_set(&xqm->qm_totaldquots, 0);
        xqm->qm_nrefs = 0;
        return xqm;
 }
@@ -1522,6 +1521,7 @@ xfs_qm_dqreclaim_one(
 
                list_del_init(&dqp->q_lru);
                qi->qi_lru_count--;
+               XQM_STATS_DEC(xs_qm_dquots_unused);
                return;
        }
 
@@ -1570,6 +1570,7 @@ xfs_qm_dqreclaim_one(
        ASSERT(dqp->q_nrefs == 0);
        list_move_tail(&dqp->q_lru, dispose_list);
        qi->qi_lru_count--;
+       XQM_STATS_DEC(xs_qm_dquots_unused);
 
        trace_xfs_dqreclaim_done(dqp);
        XQM_STATS_INC(xs_qm_dqreclaims);
Index: xfs/fs/xfs/xfs_qm.h
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.h    2012-02-01 12:26:36.000000000 +0100
+++ xfs/fs/xfs/xfs_qm.h 2012-02-01 12:30:48.365725997 +0100
@@ -46,7 +46,6 @@ extern kmem_zone_t    *qm_dqtrxzone;
  * Quota Manager (global) structure. Lives only in core.
  */
 typedef struct xfs_qm {
-       atomic_t         qm_totaldquots; /* total incore dquots */
        uint             qm_nrefs;       /* file systems with quota on */
        kmem_zone_t     *qm_dqzone;      /* dquot mem-alloc zone */
        kmem_zone_t     *qm_dqtrxzone;   /* t_dqinfo of transactions */