summaryrefslogtreecommitdiff
path: root/drivers/staging/zcache
diff options
context:
space:
mode:
authorSeth Jennings <sjenning@linux.vnet.ibm.com>2011-12-30 10:42:15 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-02-08 14:14:14 -0800
commit2a4830110b90deb4ee99b1ab8c8ebb120f27c0c8 (patch)
tree642f3ddca90439ff7fff2b76474319de2525807c /drivers/staging/zcache
parenta9d3c9e3c575ee09c905e07ae7cc1d52e2548d05 (diff)
staging: zcache: fix serialization bug in zv stats
In a multithreaded workload, the zv_curr_dist_counts and zv_cumul_dist_counts statistics are being corrupted because the increments and decrements in zv_create and zv_free are not atomic. This patch converts these statistics and their corresponding increments/decrements/reads to atomic operations. Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com> Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/zcache')
-rw-r--r--drivers/staging/zcache/zcache-main.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
index ce07087750a6..ef7c52bb1df9 100644
--- a/drivers/staging/zcache/zcache-main.c
+++ b/drivers/staging/zcache/zcache-main.c
@@ -654,8 +654,8 @@ static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
*/
static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
-static unsigned long zv_curr_dist_counts[NCHUNKS];
-static unsigned long zv_cumul_dist_counts[NCHUNKS];
+static atomic_t zv_curr_dist_counts[NCHUNKS];
+static atomic_t zv_cumul_dist_counts[NCHUNKS];
static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
struct tmem_oid *oid, uint32_t index,
@@ -674,8 +674,8 @@ static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
&page, &offset, ZCACHE_GFP_MASK);
if (unlikely(ret))
goto out;
- zv_curr_dist_counts[chunks]++;
- zv_cumul_dist_counts[chunks]++;
+ atomic_inc(&zv_curr_dist_counts[chunks]);
+ atomic_inc(&zv_cumul_dist_counts[chunks]);
zv = kmap_atomic(page, KM_USER0) + offset;
zv->index = index;
zv->oid = *oid;
@@ -697,7 +697,7 @@ static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
ASSERT_SENTINEL(zv, ZVH);
BUG_ON(chunks >= NCHUNKS);
- zv_curr_dist_counts[chunks]--;
+ atomic_dec(&zv_curr_dist_counts[chunks]);
size -= sizeof(*zv);
BUG_ON(size == 0);
INVERT_SENTINEL(zv, ZVH);
@@ -737,7 +737,7 @@ static int zv_curr_dist_counts_show(char *buf)
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
- n = zv_curr_dist_counts[i];
+ n = atomic_read(&zv_curr_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;
@@ -753,7 +753,7 @@ static int zv_cumul_dist_counts_show(char *buf)
char *p = buf;
for (i = 0; i < NCHUNKS; i++) {
- n = zv_cumul_dist_counts[i];
+ n = atomic_read(&zv_cumul_dist_counts[i]);
p += sprintf(p, "%lu ", n);
chunks += n;
sum_total_chunks += i * n;