Commit f6498b77 authored by Johannes Weiner's avatar Johannes Weiner Committed by Andrew Morton
Browse files

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: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarDavid 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b3fbd58f

Documentation/filesystems/proc.rst

+6 −0
Original line number Diff line number Diff line
@@ -964,6 +964,8 @@ Example output. You may not have all of these fields. 
    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

fs/proc/meminfo.c

+7 −0
Original line number Diff line number Diff line
@@ -86,6 +86,13 @@ static int meminfo_proc_show(struct seq_file *m, void *v) 


	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:      ",

include/linux/swap.h

+5 −0
Original line number Diff line number Diff line
@@ -620,6 +620,11 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 
}

#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)

include/linux/vm_event_item.h

+4 −0
Original line number Diff line number Diff line
@@ -136,6 +136,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, 
#ifdef CONFIG_KSM

		COW_KSM,

#endif

#ifdef CONFIG_ZSWAP

		ZSWPIN,

		ZSWPOUT,

#endif

#ifdef CONFIG_X86

		DIRECT_MAP_LEVEL2_SPLIT,

		DIRECT_MAP_LEVEL3_SPLIT,

mm/vmstat.c

+4 −0
Original line number Diff line number Diff line
@@ -1396,6 +1396,10 @@ 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",