linux-stable.git/include/linux/vm_event_item.h, branch v6.9.2

mm: memcg: add per-memcg zswap writeback stat

2023-12-12T18:57:02+00:00

Since zswap now writes back pages from memcg-specific LRUs, we now need a
new stat to show writebacks count for each memcg.

[nphamcs@gmail.com: rename ZSWP_WB to ZSWPWB]
  Link: https://lkml.kernel.org/r/20231205193307.2432803-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-5-nphamcs@gmail.com
Suggested-by: Nhat Pham 
Signed-off-by: Domenico Cerasuolo 
Signed-off-by: Nhat Pham 
Tested-by: Bagas Sanjaya 
Reviewed-by: Yosry Ahmed 
Cc: Chris Li 
Cc: Dan Streetman 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Muchun Song 
Cc: Roman Gushchin 
Cc: Seth Jennings 
Cc: Shakeel Butt 
Cc: Shuah Khan 
Cc: Vitaly Wool 
Signed-off-by: Andrew Morton

mm/vmstat: move pgdemote_* to per-node stats

2023-12-11T00:51:31+00:00

Demotion will migrate pages across nodes.  Previously, only the global
demotion statistics were accounted for.  Changed them to per-node
statistics, making it easier to observe where demotion occurs on each
node.

This will help to identify which nodes are under pressure.

This patch also make pgdemote_* behind CONFIG_NUMA_BALANCING, since
demotion is not available for !CONFIG_NUMA_BALANCING

With this patch, here is a sample where node0 node1 are DRAM,
node3 is PMEM:
Global stats:
$ grep demote /proc/vmstat
pgdemote_kswapd 254288
pgdemote_direct 113497
pgdemote_khugepaged 0

Per-node stats:
$ grep demote /sys/devices/system/node/node0/vmstat # demotion source
pgdemote_kswapd 68454
pgdemote_direct 83431
pgdemote_khugepaged 0
$ grep demote /sys/devices/system/node/node1/vmstat # demotion source
pgdemote_kswapd 185834
pgdemote_direct 30066
pgdemote_khugepaged 0
$ grep demote /sys/devices/system/node/node3/vmstat # demotion target
pgdemote_kswapd 0
pgdemote_direct 0
pgdemote_khugepaged 0

Link: https://lkml.kernel.org/r/20231103031450.1456523-1-lizhijian@fujitsu.com
Signed-off-by: Li Zhijian 
Acked-by: "Huang, Ying" 
Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Signed-off-by: Andrew Morton

mm: introduce per-VMA lock statistics

2023-04-06T03:03:01+00:00

Add a new CONFIG_PER_VMA_LOCK_STATS config option to dump extra statistics
about handling page fault under VMA lock.

Link: https://lkml.kernel.org/r/20230227173632.3292573-29-surenb@google.com
Signed-off-by: Suren Baghdasaryan 
Signed-off-by: Andrew Morton

mm: vmscan: split khugepaged stats from direct reclaim stats

2022-11-30T23:58:41+00:00

Direct reclaim stats are useful for identifying a potential source for
application latency, as well as spotting issues with kswapd.  However,
khugepaged currently distorts the picture: as a kernel thread it doesn't
impose allocation latencies on userspace, and it explicitly opts out of
kswapd reclaim.  Its activity showing up in the direct reclaim stats is
misleading.  Counting it as kswapd reclaim could also cause confusion when
trying to understand actual kswapd behavior.

Break out khugepaged from the direct reclaim counters into new
pgsteal_khugepaged, pgdemote_khugepaged, pgscan_khugepaged counters.

Test with a huge executable (CONFIG_READ_ONLY_THP_FOR_FS):

pgsteal_kswapd 1342185
pgsteal_direct 0
pgsteal_khugepaged 3623
pgscan_kswapd 1345025
pgscan_direct 0
pgscan_khugepaged 3623

Link: https://lkml.kernel.org/r/20221026180133.377671-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner 
Reported-by: Eric Bergen 
Cc: Matthew Wilcox (Oracle) 
Cc: Yang Shi 
Cc: Yosry Ahmed 
Signed-off-by: Andrew Morton

mm: remove vmacache

2022-09-27T02:46:18+00:00

By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code.  Remove the vmacache
to reduce the work in keeping it up to date and code complexity.

Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett 
Acked-by: Vlastimil Babka 
Tested-by: Yu Zhao 
Cc: Catalin Marinas 
Cc: David Hildenbrand 
Cc: David Howells 
Cc: Davidlohr Bueso 
Cc: "Matthew Wilcox (Oracle)" 
Cc: SeongJae Park 
Cc: Sven Schnelle 
Cc: Will Deacon 
Signed-off-by: Andrew Morton

mm: add DEVICE_ZONE to FOR_ALL_ZONES

2022-08-20T22:17:45+00:00

FOR_ALL_ZONES should be consistent with enum zone_type.  Otherwise,
__count_zid_vm_events have the potential to add count to wrong item when
zid is ZONE_DEVICE.

Link: https://lkml.kernel.org/r/20220807154442.GA18167@haolee.io
Signed-off-by: Hao Lee 
Cc: David Hildenbrand 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton

mm: zswap: add basic meminfo and vmstat coverage

2022-05-19T21:08:53+00:00

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 
Acked-by: David Hildenbrand 
Cc: Dan Streetman 
Cc: Michal Hocko 
Cc: Minchan Kim 
Cc: Roman Gushchin 
Cc: Seth Jennings 
Cc: Shakeel Butt 
Signed-off-by: Andrew Morton

mm/vmstat: add events for ksm cow

2022-04-29T06:16:16+00:00

Users may use ksm by calling madvise(, , MADV_MERGEABLE) when they want to
save memory, it's a tradeoff by suffering delay on ksm cow.  Users can get
to know how much memory ksm saved by reading
/sys/kernel/mm/ksm/pages_sharing, but they don't know what's the costs of
ksm cow, and this is important of some delay sensitive tasks.

So add ksm cow events to help users evaluate whether or how to use ksm. 
Also update Documentation/admin-guide/mm/ksm.rst with new added events.

Link: https://lkml.kernel.org/r/20220331035616.2390805-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang 
Reviewed-by: David Hildenbrand 
Reviewed-by: xu xin 
Reviewed-by: Ran Xiaokai 
Cc: Matthew Wilcox (Oracle) 
Cc: Jonathan Corbet 
Cc: Dave Hansen 
Cc: Saravanan D 
Cc: Minchan Kim 
Cc: John Hubbard 
Signed-off-by: Andrew Morton

mm/vmstat: add event for ksm swapping in copy

2022-03-22T22:57:09+00:00

When faults in from swap what used to be a KSM page and that page had been
swapped in before, system has to make a copy, and leaves remerging the
pages to a later pass of ksmd.

That is not good for performace, we'd better to reduce this kind of copy.
There are some ways to reduce it, for example lessen swappiness or
madvise(, , MADV_MERGEABLE) range.  So add this event to support doing
this tuning.  Just like this patch: "mm, THP, swap: add THP swapping out
fallback counting".

Link: https://lkml.kernel.org/r/20220113023839.758845-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang 
Reviewed-by: Ran Xiaokai 
Cc: Hugh Dickins 
Cc: Yang Shi 
Cc: Dave Hansen 
Cc: Saravanan D 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/vmstat: add events for THP max_ptes_* exceeds

2022-01-15T14:30:29+00:00

There are interfaces to adjust max_ptes_none, max_ptes_swap,
max_ptes_shared values, see
  /sys/kernel/mm/transparent_hugepage/khugepaged/.

But system administrator may not know which value is the best.  So Add
those events to support adjusting max_ptes_* to suitable values.

For example, if default max_ptes_swap value causes too much failures,
and system uses zram whose IO is fast, administrator could increase
max_ptes_swap until THP_SCAN_EXCEED_SWAP_PTE not increase anymore.

Link: https://lkml.kernel.org/r/20211225094036.574157-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang 
Cc: "Huang, Ying" 
Cc: Dave Hansen 
Cc: Minchan Kim 
Cc: Saravanan D 
Cc: Mike Kravetz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds