The patch titled
Subject: mm: zswap: add basic meminfo and vmstat coverage
has been added to the -mm mm-unstable branch. Its filename is
mm-zswap-add-basic-meminfo-and-vmstat-coverage.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-add-basic-meminfo-and-vmstat-coverage.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: 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@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Dan Streetman <ddstreet@xxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Seth Jennings <sjenning@xxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/proc.rst | 6 ++++++
fs/proc/meminfo.c | 7 +++++++
include/linux/swap.h | 5 +++++
include/linux/vm_event_item.h | 4 ++++
mm/vmstat.c | 4 ++++
mm/zswap.c | 13 ++++++-------
6 files changed, 32 insertions(+), 7 deletions(-)
--- a/Documentation/filesystems/proc.rst~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/Documentation/filesystems/proc.rst
@@ -964,6 +964,8 @@ Example output. You may not have all of
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
+ Zswap: 1904 kB
+ Zswapped: 7792 kB
Dirty: 12 kB
Writeback: 0 kB
AnonPages: 4654780 kB
@@ -1055,6 +1057,10 @@ SwapTotal
SwapFree
Memory which has been evicted from RAM, and is temporarily
on the disk
+Zswap
+ Memory consumed by the zswap backend (compressed size)
+Zswapped
+ Amount of anonymous memory stored in zswap (original size)
Dirty
Memory which is waiting to get written back to the disk
Writeback
--- a/fs/proc/meminfo.c~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/fs/proc/meminfo.c
@@ -86,6 +86,13 @@ static int meminfo_proc_show(struct seq_
show_val_kb(m, "SwapTotal: ", i.totalswap);
show_val_kb(m, "SwapFree: ", i.freeswap);
+#ifdef CONFIG_ZSWAP
+ seq_printf(m, "Zswap: %8lu kB\n",
+ (unsigned long)(zswap_pool_total_size >> 10));
+ seq_printf(m, "Zswapped: %8lu kB\n",
+ (unsigned long)atomic_read(&zswap_stored_pages) <<
+ (PAGE_SHIFT - 10));
+#endif
show_val_kb(m, "Dirty: ",
global_node_page_state(NR_FILE_DIRTY));
show_val_kb(m, "Writeback: ",
--- a/include/linux/swap.h~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/include/linux/swap.h
@@ -625,6 +625,11 @@ static inline int mem_cgroup_swappiness(
}
#endif
+#ifdef CONFIG_ZSWAP
+extern u64 zswap_pool_total_size;
+extern atomic_t zswap_stored_pages;
+#endif
+
#if defined(CONFIG_SWAP) && defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
extern void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask);
static inline void cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask)
--- a/include/linux/vm_event_item.h~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/include/linux/vm_event_item.h
@@ -132,6 +132,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS
#ifdef CONFIG_KSM
COW_KSM,
#endif
+#ifdef CONFIG_ZSWAP
+ ZSWPIN,
+ ZSWPOUT,
+#endif
#ifdef CONFIG_X86
DIRECT_MAP_LEVEL2_SPLIT,
DIRECT_MAP_LEVEL3_SPLIT,
--- a/mm/vmstat.c~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/mm/vmstat.c
@@ -1392,6 +1392,10 @@ const char * const vmstat_text[] = {
#ifdef CONFIG_KSM
"cow_ksm",
#endif
+#ifdef CONFIG_ZSWAP
+ "zswpin",
+ "zswpout",
+#endif
#ifdef CONFIG_X86
"direct_map_level2_splits",
"direct_map_level3_splits",
--- a/mm/zswap.c~mm-zswap-add-basic-meminfo-and-vmstat-coverage
+++ a/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
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
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
kfree(tmp);
BUG_ON(ret);
-
+stats:
+ count_vm_event(ZSWPIN);
freeentry:
spin_lock(&tree->lock);
zswap_entry_put(tree, entry);
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
documentation-filesystems-proc-update-meminfo-section.patch
mm-kconfig-move-swap-and-slab-config-options-to-the-mm-section.patch
mm-kconfig-group-swap-slab-hotplug-and-thp-options-into-submenus.patch
mm-kconfig-simplify-zswap-configuration.patch
mm-zswap-add-basic-meminfo-and-vmstat-coverage.patch
zswap-memcg-accounting.patch
