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authorJohannes Weiner <hannes@cmpxchg.org>2022-05-19 14:08:53 -0700
committerakpm <akpm@linux-foundation.org>2022-05-19 14:08:53 -0700
commitf6498b776d280b30a4614d8261840961e993c2c8 (patch)
treeb35704e2a62cc7630d06658fc6faaeba24b18e2a /mm/zswap.c
parentb3fbd58fcbb10725a1314688e03b1af6827c42f9 (diff)
mm: zswap: add basic meminfo and vmstat coverage
Currently it requires poking at debugfs to figure out the size and population of the zswap cache on a host. There are no counters for reads and writes against the cache. As a result, it's difficult to understand zswap behavior on production systems. Print zswap memory consumption and how many pages are zswapped out in /proc/meminfo. Count zswapouts and zswapins in /proc/vmstat. Link: https://lkml.kernel.org/r/20220510152847.230957-6-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Roman Gushchin <guro@fb.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/zswap.c')
-rw-r--r--mm/zswap.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/mm/zswap.c b/mm/zswap.c
index 2c5db4cbedea..e3c16a70f533 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -42,9 +42,9 @@
* statistics
**********************************/
/* Total bytes used by the compressed storage */
-static u64 zswap_pool_total_size;
+u64 zswap_pool_total_size;
/* The number of compressed pages currently stored in zswap */
-static atomic_t zswap_stored_pages = ATOMIC_INIT(0);
+atomic_t zswap_stored_pages = ATOMIC_INIT(0);
/* The number of same-value filled pages currently stored in zswap */
static atomic_t zswap_same_filled_pages = ATOMIC_INIT(0);
@@ -1243,6 +1243,7 @@ insert_entry:
/* update stats */
atomic_inc(&zswap_stored_pages);
zswap_update_total_size();
+ count_vm_event(ZSWPOUT);
return 0;
@@ -1285,11 +1286,10 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
zswap_fill_page(dst, entry->value);
kunmap_atomic(dst);
ret = 0;
- goto freeentry;
+ goto stats;
}
if (!zpool_can_sleep_mapped(entry->pool->zpool)) {
-
tmp = kmalloc(entry->length, GFP_ATOMIC);
if (!tmp) {
ret = -ENOMEM;
@@ -1304,10 +1304,8 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
src += sizeof(struct zswap_header);
if (!zpool_can_sleep_mapped(entry->pool->zpool)) {
-
memcpy(tmp, src, entry->length);
src = tmp;
-
zpool_unmap_handle(entry->pool->zpool, entry->handle);
}
@@ -1326,7 +1324,8 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset,
kfree(tmp);
BUG_ON(ret);
-
+stats:
+ count_vm_event(ZSWPIN);
freeentry:
spin_lock(&tree->lock);
zswap_entry_put(tree, entry);