[PATCH 5/7] xfs: use per-cpu data for the quota statistics

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

Use the same per-cpu scheme used in the main XFS statistics, as well as
the VFS inode and dcache statistics for the quota code.

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

---
 fs/xfs/xfs_dquot.c    |    6 +++---
 fs/xfs/xfs_qm.c       |    6 +++---
 fs/xfs/xfs_qm_stats.c |   28 +++++++++++++++++-----------
 fs/xfs/xfs_qm_stats.h |   11 ++++++++---
 4 files changed, 31 insertions(+), 20 deletions(-)

Index: xfs/fs/xfs/xfs_dquot.c
===================================================================
--- xfs.orig/fs/xfs/xfs_dquot.c 2012-02-01 12:29:56.000000000 +0100
+++ xfs/fs/xfs/xfs_dquot.c      2012-02-01 12:30:02.839305968 +0100
@@ -666,13 +666,13 @@ restart:
                mutex_unlock(&mp->m_quotainfo->qi_tree_lock);
 
                trace_xfs_dqget_hit(dqp);
-               XQM_STATS_INC(xqmstats.xs_qm_dqcachehits);
+               XQM_STATS_INC(xs_qm_dqcachehits);
                *O_dqpp = dqp;
                return 0;
        }
        mutex_unlock(&mp->m_quotainfo->qi_tree_lock);
 
-       XQM_STATS_INC(xqmstats.xs_qm_dqcachemisses);
+       XQM_STATS_INC(xs_qm_dqcachemisses);
 
        /*
         * Dquot cache miss. We don't want to keep the inode lock across
@@ -736,7 +736,7 @@ restart:
                mutex_unlock(&mp->m_quotainfo->qi_tree_lock);
                trace_xfs_dqget_dup(dqp);
                xfs_qm_dqdestroy(dqp);
-               XQM_STATS_INC(xqmstats.xs_qm_dquot_dups);
+               XQM_STATS_INC(xs_qm_dquot_dups);
                goto restart;
        }
 
Index: xfs/fs/xfs/xfs_qm.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm.c    2012-02-01 12:29:56.000000000 +0100
+++ xfs/fs/xfs/xfs_qm.c 2012-02-01 12:30:26.685843449 +0100
@@ -1518,7 +1518,7 @@ xfs_qm_dqreclaim_one(
                xfs_dqunlock(dqp);
 
                trace_xfs_dqreclaim_want(dqp);
-               XQM_STATS_INC(xqmstats.xs_qm_dqwants);
+               XQM_STATS_INC(xs_qm_dqwants);
 
                list_del_init(&dqp->q_lru);
                qi->qi_lru_count--;
@@ -1572,7 +1572,7 @@ xfs_qm_dqreclaim_one(
        qi->qi_lru_count--;
 
        trace_xfs_dqreclaim_done(dqp);
-       XQM_STATS_INC(xqmstats.xs_qm_dqreclaims);
+       XQM_STATS_INC(xs_qm_dqreclaims);
        return;
 
 out_busy:
@@ -1584,7 +1584,7 @@ out_busy:
        list_move_tail(&dqp->q_lru, &qi->qi_lru_list);
 
        trace_xfs_dqreclaim_busy(dqp);
-       XQM_STATS_INC(xqmstats.xs_qm_dqreclaim_misses);
+       XQM_STATS_INC(xs_qm_dqreclaim_misses);
 }
 
 STATIC int
Index: xfs/fs/xfs/xfs_qm_stats.c
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_stats.c      2012-02-01 12:22:12.000000000 +0100
+++ xfs/fs/xfs/xfs_qm_stats.c   2012-02-01 12:30:02.842639283 +0100
@@ -36,7 +36,16 @@
 #include "xfs_buf_item.h"
 #include "xfs_qm.h"
 
-struct xqmstats xqmstats;
+DEFINE_PER_CPU(struct xqmstats, xqmstats);
+
+static int xqmstats_sum(int idx)
+{
+       int val = 0, cpu;
+
+       for_each_possible_cpu(cpu)
+               val += *(((__u32 *)&per_cpu(xqmstats, cpu) + idx));
+       return max(val, 0);
+}
 
 static int xqm_proc_show(struct seq_file *m, void *v)
 {
@@ -64,16 +73,13 @@ static const struct file_operations xqm_
 
 static int xqmstat_proc_show(struct seq_file *m, void *v)
 {
-       /* quota performance statistics */
-       seq_printf(m, "qm %u %u %u %u %u %u %u %u\n",
-                       xqmstats.xs_qm_dqreclaims,
-                       xqmstats.xs_qm_dqreclaim_misses,
-                       xqmstats.xs_qm_dquot_dups,
-                       xqmstats.xs_qm_dqcachemisses,
-                       xqmstats.xs_qm_dqcachehits,
-                       xqmstats.xs_qm_dqwants,
-                       xqmstats.xs_qm_dqshake_reclaims,
-                       xqmstats.xs_qm_dqinact_reclaims);
+       int j;
+
+       seq_printf(m, "qm");
+       for (j = 0; j < XQMSTAT_END_XQMSTAT; j++)
+               seq_printf(m, " %u", xqmstats_sum(j));
+       seq_putc(m, '\n');
+
        return 0;
 }
 
Index: xfs/fs/xfs/xfs_qm_stats.h
===================================================================
--- xfs.orig/fs/xfs/xfs_qm_stats.h      2012-02-01 12:05:06.000000000 +0100
+++ xfs/fs/xfs/xfs_qm_stats.h   2012-02-01 12:30:02.842639283 +0100
@@ -32,18 +32,23 @@ struct xqmstats {
        __uint32_t              xs_qm_dqwants;
        __uint32_t              xs_qm_dqshake_reclaims;
        __uint32_t              xs_qm_dqinact_reclaims;
+#define XQMSTAT_END_XQMSTAT    8
 };
 
-extern struct xqmstats xqmstats;
+DECLARE_PER_CPU(struct xqmstats, xqmstats);
 
-# define XQM_STATS_INC(count)  ( (count)++ )
+/*
+ * We don't disable preempt, not too worried about poking the
+ * wrong CPU's stat for now (also aggregated before reporting).
+ */
+# define XQM_STATS_INC(v)      (per_cpu(xqmstats, current_cpu()).v++)
 
 extern void xfs_qm_init_procfs(void);
 extern void xfs_qm_cleanup_procfs(void);
 
 #else
 
-# define XQM_STATS_INC(count)  do { } while (0)
+# define XQM_STATS_INC(v)      do { } while (0)
 
 static inline void xfs_qm_init_procfs(void) { };
 static inline void xfs_qm_cleanup_procfs(void) { };