mm/vmstat: revert "fix a W=1 clang compiler warning"

Commit 75b5ab134bb5 enabled -Wenum-enum-conversion in W=1 builds. Commit
30c2de0a267c ("mm/vmstat: fix a W=1 clang compiler warning") fixed a
-W

mm/vmstat: revert "fix a W=1 clang compiler warning"

Commit 75b5ab134bb5 enabled -Wenum-enum-conversion in W=1 builds. Commit
30c2de0a267c ("mm/vmstat: fix a W=1 clang compiler warning") fixed a
-Wenum-enum-conversion warning. Commit 8f6629c004b1 removed the
-Wenum-enum-conversion option again from W=1 builds. Since the W=1
compiler warning fix is no longer necessary, revert it.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Bart Van Assche <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Ivan Shapovalov <[email protected]>
Cc: David Laight <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: vmstat: move sysctls to mm/vmstat.c

This moves all vmstat related sysctls to its own file, removes useless
extern variable declarations, and do some related clean-ups. To avoid
compiler warnings

mm: vmstat: move sysctls to mm/vmstat.c

This moves all vmstat related sysctls to its own file, removes useless
extern variable declarations, and do some related clean-ups. To avoid
compiler warnings when CONFIG_PROC_FS is not defined, add the macro
definition CONFIG_PROC_FS ahead CONFIG_NUMA in vmstat.c.

Signed-off-by: Kaixiong Yu <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

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mm/vmstat: fix a W=1 clang compiler warning

Fix the following clang compiler warning that is reported if the kernel is
built with W=1:

./include/linux/vmstat.h:518:36: error: arithmetic between dif

mm/vmstat: fix a W=1 clang compiler warning

Fix the following clang compiler warning that is reported if the kernel is
built with W=1:

./include/linux/vmstat.h:518:36: error: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Werror,-Wenum-enum-conversion]
518 | return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
| ~~~~~~~~~~~ ^ ~~~


Link: https://lkml.kernel.org/r/[email protected]
Fixes: 9d7ea9a297e6 ("mm/vmstat: add helpers to get vmstat item names for each enum type")
Signed-off-by: Bart Van Assche <[email protected]>
Cc: Konstantin Khlebnikov <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm,memcg: provide per-cgroup counters for NUMA balancing operations

The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring a

mm,memcg: provide per-cgroup counters for NUMA balancing operations

The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring and tuning
containerized workloads on machines equipped with tiered memory.

Different containers in the system may experience drastically different
memory tiering actions that cannot be distinguished from the global
counters alone.

For example, a container running a workload that has a much hotter memory
accesses will likely see more promotions and fewer demotions, potentially
depriving a colocated container of top tier memory to such an extent that
its performance degrades unacceptably.

For another example, some containers may exhibit longer periods between
data reuse, causing much more numa_hint_faults than numa_pages_migrated.
In this case, tuning hot_threshold_ms may be appropriate, but the signal
can easily be lost if only global counters are available.

In the long term, we hope to introduce per-cgroup control of promotion and
demotion actions to implement memory placement policies in tiering.

This patch set adds seven counters to memory.stat in a cgroup:
numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd,
pgdemote_khugepaged, pgdemote_direct and pgpromote_success. pgdemote_*
and pgpromote_success are also available in memory.numa_stat.

count_memcg_events_mm() is added to count multiple event occurrences at
once, and get_mem_cgroup_from_folio() is added because we need to get a
reference to the memcg of a folio before it's migrated to track
numa_pages_migrated. The accounting of PGDEMOTE_* is moved to
shrink_inactive_list() before being changed to per-cgroup.

[[email protected]: add documentation of the memcg counters in cgroup-v2.rst]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kaiyang Zhao <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Roman Gushchin <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Wei Xu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: don't account memmap per-node

Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Seg

mm: don't account memmap per-node

Fix invalid access to pgdat during hot-remove operation:
ndctl users reported a GPF when trying to destroy a namespace:
$ ndctl destroy-namespace all -r all -f
Segmentation fault
dmesg:
Oops: general protection fault, probably for
non-canonical address 0xdffffc0000005650: 0000 [#1] PREEMPT SMP KASAN
PTI
KASAN: probably user-memory-access in range
[0x000000000002b280-0x000000000002b287]
CPU: 26 UID: 0 PID: 1868 Comm: ndctl Not tainted 6.11.0-rc1 #1
Hardware name: Dell Inc. PowerEdge R640/08HT8T, BIOS
2.20.1 09/13/2023
RIP: 0010:mod_node_page_state+0x2a/0x110

cxl-test users report a GPF when trying to unload the test module:
$ modrpobe -r cxl-test
dmesg
BUG: unable to handle page fault for address: 0000000000004200
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 0 UID: 0 PID: 1076 Comm: modprobe Tainted: G O N 6.11.0-rc1 #197
Tainted: [O]=OOT_MODULE, [N]=TEST
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/15
RIP: 0010:mod_node_page_state+0x6/0x90

Currently, when memory is hot-plugged or hot-removed the accounting is
done based on the assumption that memmap is allocated from the same node
as the hot-plugged/hot-removed memory, which is not always the case.

In addition, there are challenges with keeping the node id of the memory
that is being remove to the time when memmap accounting is actually
performed: since this is done after remove_pfn_range_from_zone(), and
also after remove_memory_block_devices(). Meaning that we cannot use
pgdat nor walking though memblocks to get the nid.

Given all of that, account the memmap overhead system wide instead.

For this we are going to be using global atomic counters, but given that
memmap size is rarely modified, and normally is only modified either
during early boot when there is only one CPU, or under a hotplug global
mutex lock, therefore there is no need for per-cpu optimizations.

Also, while we are here rename nr_memmap to nr_memmap_pages, and
nr_memmap_boot to nr_memmap_boot_pages to be self explanatory that the
units are in page count.

[[email protected]: address a few nits from David Hildenbrand]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <[email protected]>
Reported-by: Yi Zhang <[email protected]>
Closes: https://lore.kernel.org/linux-cxl/CAHj4cs9Ax1=CoJkgBGP_+sNu6-6=6v=_L-ZBZY0bVLD3wUWZQg@mail.gmail.com
Reported-by: Alison Schofield <[email protected]>
Closes: https://lore.kernel.org/linux-mm/Zq0tPd2h6alFz8XF@aschofie-mobl2/#t
Tested-by: Dan Williams <[email protected]>
Tested-by: Alison Schofield <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: David Rientjes <[email protected]>
Tested-by: Yi Zhang <[email protected]>
Cc: Domenico Cerasuolo <[email protected]>
Cc: Fan Ni <[email protected]>
Cc: Joel Granados <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Li Zhijian <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Sourav Panda <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yosry Ahmed <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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mm: add system wide stats items category

/proc/vmstat contains events and stats, events can only grow, but stats
can grow and shrink.

vmstat has the following:
-------------------------
NR_VM_ZONE_

mm: add system wide stats items category

/proc/vmstat contains events and stats, events can only grow, but stats
can grow and shrink.

vmstat has the following:
-------------------------
NR_VM_ZONE_STAT_ITEMS: per-zone stats
NR_VM_NUMA_EVENT_ITEMS: per-numa events
NR_VM_NODE_STAT_ITEMS: per-numa stats
NR_VM_WRITEBACK_STAT_ITEMS: system-wide background-writeback and
dirty-throttling tresholds.
NR_VM_EVENT_ITEMS: system-wide events
-------------------------

Rename NR_VM_WRITEBACK_STAT_ITEMS to NR_VM_STAT_ITEMS, to track the
system-wide stats, we are going to add per-page metadata stats to this
category in the next patch.

Also delete unused writeback_stat_name().

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <[email protected]>
Suggested-by: Yosry Ahmed <[email protected]>
Tested-by: Alison Schofield <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Acked-by: David Rientjes <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Domenico Cerasuolo <[email protected]>
Cc: Joel Granados <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Li Zhijian <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Sourav Panda <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Yi Zhang <[email protected]>
Cc: Fan Ni <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ct

sysctl: treewide: constify the ctl_table argument of proc_handlers

const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.

This patch has been generated by the following coccinelle script:

```
virtual patch

@r1@
identifier ctl, write, buffer, lenp, ppos;
identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos);

@r2@
identifier func, ctl, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos)
{ ... }

@r3@
identifier func;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int , void *, size_t *, loff_t *);

@r4@
identifier func, ctl;
@@

int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int , void *, size_t *, loff_t *);

@r5@
identifier func, write, buffer, lenp, ppos;
@@

int func(
- struct ctl_table *
+ const struct ctl_table *
,int write, void *buffer, size_t *lenp, loff_t *ppos);

```

* Code formatting was adjusted in xfs_sysctl.c to comply with code
conventions. The xfs_stats_clear_proc_handler,
xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
adjusted.

* The ctl_table argument in proc_watchdog_common was const qualified.
This is called from a proc_handler itself and is calling back into
another proc_handler, making it necessary to change it as part of the
proc_handler migration.

Co-developed-by: Thomas Weißschuh <[email protected]>
Signed-off-by: Thomas Weißschuh <[email protected]>
Co-developed-by: Joel Granados <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

show more ...

mm: report per-page metadata information

Today, we do not have any observability of per-page metadata and how much
it takes away from the machine capacity. Thus, we want to describe the
amount of m

mm: report per-page metadata information

Today, we do not have any observability of per-page metadata and how much
it takes away from the machine capacity. Thus, we want to describe the
amount of memory that is going towards per-page metadata, which can vary
depending on build configuration, machine architecture, and system use.

This patch adds 2 fields to /proc/vmstat that can used as shown below:

Accounting per-page metadata allocated by boot-allocator:
/proc/vmstat:nr_memmap_boot * PAGE_SIZE

Accounting per-page metadata allocated by buddy-allocator:
/proc/vmstat:nr_memmap * PAGE_SIZE

Accounting total Perpage metadata allocated on the machine:
(/proc/vmstat:nr_memmap_boot +
/proc/vmstat:nr_memmap) * PAGE_SIZE

Utility for userspace:

Observability: Describe the amount of memory overhead that is going to
per-page metadata on the system at any given time since this overhead is
not currently observable.

Debugging: Tracking the changes or absolute value in struct pages can help
detect anomalies as they can be correlated with other metrics in the
machine (e.g., memtotal, number of huge pages, etc).

page_ext overheads: Some kernel features such as page_owner
page_table_check that use page_ext can be optionally enabled via kernel
parameters. Having the total per-page metadata information helps users
precisely measure impact. Furthermore, page-metadata metrics will reflect
the amount of struct pages reliquished (or overhead reduced) when
hugetlbfs pages are reserved which will vary depending on whether hugetlb
vmemmap optimization is enabled or not.

For background and results see:
lore.kernel.org/all/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sourav Panda <[email protected]>
Acked-by: David Rientjes <[email protected]>
Reviewed-by: Pasha Tatashin <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Chen Linxuan <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Ivan Babrou <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport (IBM) <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Tomas Mudrunka <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Yang Yang <[email protected]>
Cc: Yosry Ahmed <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: page_alloc: consolidate free page accounting

Free page accounting currently happens a bit too high up the call stack,
where it has to deal with guard pages, compaction capturing, block
stealing

mm: page_alloc: consolidate free page accounting

Free page accounting currently happens a bit too high up the call stack,
where it has to deal with guard pages, compaction capturing, block
stealing and even page isolation. This is subtle and fragile, and makes
it difficult to hack on the code.

Now that type violations on the freelists have been fixed, push the
accounting down to where pages enter and leave the freelist.

[[email protected]: undo unrelated drive-by line wrap]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: remove unused page parameter from account_freepages()]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: fix free page accounting]
Link: https://lkml.kernel.org/r/a2a48baca69f103aa431fd201f8a06e3b95e203d.1712648441.git.baolin.wang@linux.alibaba.com
[[email protected]: avoid defining unused function]
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Signed-off-by: Andy Shevchenko <[email protected]>
Signed-off-by: Baolin Wang <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Tested-by: Baolin Wang <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm/memcontrol: remove __mod_lruvec_page_state()

There are no more callers of __mod_lruvec_page_state(), so convert the
implementation to __lruvec_stat_mod_folio(), removing two calls to
compound_hea

mm/memcontrol: remove __mod_lruvec_page_state()

There are no more callers of __mod_lruvec_page_state(), so convert the
implementation to __lruvec_stat_mod_folio(), removing two calls to
compound_head() (one explicit, one hidden inside page_memcg()).

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Acked-by: Shakeel Butt <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Cc: Hyeonggon Yoo <[email protected]>
Cc: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: remove inc/dec lruvec page state functions

Patch series "Remove some lruvec page accounting functions", v2.

Some functions are now unused; remove them. Make
__mod_lruvec_page_state() unused an

mm: remove inc/dec lruvec page state functions

Patch series "Remove some lruvec page accounting functions", v2.

Some functions are now unused; remove them. Make
__mod_lruvec_page_state() unused and then remove it.


This patch (of 6):

All callers of these have been converted to their folio equivalents.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Cc: Hyeonggon Yoo <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: introduce per-VMA lock statistics

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/2023022717

mm: introduce per-VMA lock statistics

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/[email protected]
Signed-off-by: Suren Baghdasaryan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm: remove vmacache

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

mm: remove vmacache

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/[email protected]
Signed-off-by: Liam R. Howlett <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Tested-by: Yu Zhao <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: David Howells <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Cc: SeongJae Park <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

show more ...

mm/workingset: Convert workingset_refault() to take a folio

This nets us 178 bytes of savings from removing calls to compound_head.
The three callers all grow a little, but each of them will be conv

mm/workingset: Convert workingset_refault() to take a folio

This nets us 178 bytes of savings from removing calls to compound_head.
The three callers all grow a little, but each of them will be converted
to use folios soon, so that's fine.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: David Howells <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>

show more ...

mm/vmstat: Add functions to account folio statistics

Allow page counters to be more readily modified by callers which have
a folio. Name these wrappers with 'stat' instead of 'state' as requested
b

mm/vmstat: Add functions to account folio statistics

Allow page counters to be more readily modified by callers which have
a folio. Name these wrappers with 'stat' instead of 'state' as requested
by Linus here:
https://lore.kernel.org/linux-mm/CAHk-=wj847SudR-kt+46fT3+xFFgiwpgThvm7DJWGdi4cVrbnQ@mail.gmail.com/
No change to generated code.

Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Acked-by: Jeff Layton <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Reviewed-by: William Kucharski <[email protected]>
Reviewed-by: David Howells <[email protected]>
Acked-by: Mike Rapoport <[email protected]>

show more ...

mm/page_alloc: batch the accounting updates in the bulk allocator

Now that the zone_statistics are simple counters that do not require
special protection, the bulk allocator accounting updates can b

mm/page_alloc: batch the accounting updates in the bulk allocator

Now that the zone_statistics are simple counters that do not require
special protection, the bulk allocator accounting updates can be batch
updated without adding too much complexity with protected RMW updates or
using xchg.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

mm/vmstat: inline NUMA event counter updates

__count_numa_event is small enough to be treated similarly to
__count_vm_event so inline it.

Link: https://lkml.kernel.org/r/20210512095458.30632-5-mgor

mm/vmstat: inline NUMA event counter updates

__count_numa_event is small enough to be treated similarly to
__count_vm_event so inline it.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

mm/vmstat: convert NUMA statistics to basic NUMA counters

NUMA statistics are maintained on the zone level for hits, misses, foreign
etc but nothing relies on them being perfectly accurate for funct

mm/vmstat: convert NUMA statistics to basic NUMA counters

NUMA statistics are maintained on the zone level for hits, misses, foreign
etc but nothing relies on them being perfectly accurate for functional
correctness. The counters are used by userspace to get a general overview
of a workloads NUMA behaviour but the page allocator incurs a high cost to
maintain perfect accuracy similar to what is required for a vmstat like
NR_FREE_PAGES. There even is a sysctl vm.numa_stat to allow userspace to
turn off the collection of NUMA statistics like NUMA_HIT.

This patch converts NUMA_HIT and friends to be NUMA events with similar
accuracy to VM events. There is a possibility that slight errors will be
introduced but the overall trend as seen by userspace will be similar.
The counters are no longer updated from vmstat_refresh context as it is
unnecessary overhead for counters that may never be read by userspace.
Note that counters could be maintained at the node level to save space but
it would have a user-visible impact due to /proc/zoneinfo.

[[email protected]: Fix misplaced closing brace for !CONFIG_NUMA]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm/page_alloc: split per cpu page lists and zone stats

The PCP (per-cpu page allocator in page_alloc.c) shares locking
requirements with vmstat and the zone lock which is inconvenient and
causes som

mm/page_alloc: split per cpu page lists and zone stats

The PCP (per-cpu page allocator in page_alloc.c) shares locking
requirements with vmstat and the zone lock which is inconvenient and
causes some issues. For example, the PCP list and vmstat share the same
per-cpu space meaning that it's possible that vmstat updates dirty cache
lines holding per-cpu lists across CPUs unless padding is used. Second,
PREEMPT_RT does not want to disable IRQs for too long in the page
allocator.

This series splits the locking requirements and uses locks types more
suitable for PREEMPT_RT, reduces the time when special locking is required
for stats and reduces the time when IRQs need to be disabled on
!PREEMPT_RT kernels.

Why local_lock? PREEMPT_RT considers the following sequence to be unsafe
as documented in Documentation/locking/locktypes.rst

local_irq_disable();
spin_lock(&lock);

The pcp allocator has this sequence for rmqueue_pcplist (local_irq_save)
-> __rmqueue_pcplist -> rmqueue_bulk (spin_lock). While it's possible to
separate this out, it generally means there are points where we enable
IRQs and reenable them again immediately. To prevent a migration and the
per-cpu pointer going stale, migrate_disable is also needed. That is a
custom lock that is similar, but worse, than local_lock. Furthermore, on
PREEMPT_RT, it's undesirable to leave IRQs disabled for too long. By
converting to local_lock which disables migration on PREEMPT_RT, the
locking requirements can be separated and start moving the protections for
PCP, stats and the zone lock to PREEMPT_RT-safe equivalent locking. As a
bonus, local_lock also means that PROVE_LOCKING does something useful.

After that, it's obvious that zone_statistics incurs too much overhead and
leaves IRQs disabled for longer than necessary on !PREEMPT_RT kernels.
zone_statistics uses perfectly accurate counters requiring IRQs be
disabled for parallel RMW sequences when inaccurate ones like vm_events
would do. The series makes the NUMA statistics (NUMA_HIT and friends)
inaccurate counters that then require no special protection on
!PREEMPT_RT.

The bulk page allocator can then do stat updates in bulk with IRQs enabled
which should improve the efficiency. Technically, this could have been
done without the local_lock and vmstat conversion work and the order
simply reflects the timing of when different series were implemented.

Finally, there are places where we conflate IRQs being disabled for the
PCP with the IRQ-safe zone spinlock. The remainder of the series reduces
the scope of what is protected by disabled IRQs on !PREEMPT_RT kernels.
By the end of the series, page_alloc.c does not call local_irq_save so the
locking scope is a bit clearer. The one exception is that modifying
NR_FREE_PAGES still happens in places where it's known the IRQs are
disabled as it's harmless for PREEMPT_RT and would be expensive to split
the locking there.

No performance data is included because despite the overhead of the stats,
it's within the noise for most workloads on !PREEMPT_RT. However, Jesper
Dangaard Brouer ran a page allocation microbenchmark on a E5-1650 v4 @
3.60GHz CPU on the first version of this series. Focusing on the array
variant of the bulk page allocator reveals the following.

(CPU: Intel(R) Xeon(R) CPU E5-1650 v4 @ 3.60GHz)
ARRAY variant: time_bulk_page_alloc_free_array: step=bulk size

Baseline Patched
1 56.383 54.225 (+3.83%)
2 40.047 35.492 (+11.38%)
3 37.339 32.643 (+12.58%)
4 35.578 30.992 (+12.89%)
8 33.592 29.606 (+11.87%)
16 32.362 28.532 (+11.85%)
32 31.476 27.728 (+11.91%)
64 30.633 27.252 (+11.04%)
128 30.596 27.090 (+11.46%)

While this is a positive outcome, the series is more likely to be
interesting to the RT people in terms of getting parts of the PREEMPT_RT
tree into mainline.

This patch (of 9):

The per-cpu page allocator lists and the per-cpu vmstat deltas are stored
in the same struct per_cpu_pages even though vmstats have no direct impact
on the per-cpu page lists. This is inconsistent because the vmstats for a
node are stored on a dedicated structure. The bigger issue is that the
per_cpu_pages structure is not cache-aligned and stat updates either cache
conflict with adjacent per-cpu lists incurring a runtime cost or padding
is required incurring a memory cost.

This patch splits the per-cpu pagelists and the vmstat deltas into
separate structures. It's mostly a mechanical conversion but some
variable renaming is done to clearly distinguish the per-cpu pages
structure (pcp) from the vmstats (pzstats).

Superficially, this appears to increase the size of the per_cpu_pages
structure but the movement of expire fills a structure hole so there is no
impact overall.

[[email protected]: make it W=1 cleaner]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: make it W=1 even cleaner]
Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: check struct per_cpu_zonestat has a non-zero size]
[[email protected]: Init zone->per_cpu_zonestats properly]

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Chuck Lever <[email protected]>
Cc: Jesper Dangaard Brouer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Sebastian Andrzej Siewior <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: page-writeback: simplify memcg handling in test_clear_page_writeback()

Page writeback doesn't hold a page reference, which allows truncate to
free a page the second PageWriteback is cleared. Th

mm: page-writeback: simplify memcg handling in test_clear_page_writeback()

Page writeback doesn't hold a page reference, which allows truncate to
free a page the second PageWriteback is cleared. This used to require
special attention in test_clear_page_writeback(), where we had to be
careful not to rely on the unstable page->memcg binding and look up all
the necessary information before clearing the writeback flag.

Since commit 073861ed77b6 ("mm: fix VM_BUG_ON(PageTail) and
BUG_ON(PageWriteback)") test_clear_page_writeback() is called with an
explicit reference on the page, and this dance is no longer needed.

Use unlock_page_memcg() and dec_lruvec_page_state() directly.

This removes the last user of the lock_page_memcg() return value, change
it to void. Touch up the comments in there as well. This also removes
the last extern user of __unlock_page_memcg(), make it static. Further,
it removes the last user of dec_lruvec_state(), delete it, along with a
few other unused helpers.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Roman Gushchin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: vmstat: add some comments on internal storage of byte items

Byte-accounted items are used for slab object accounting at the cgroup
level, because the objects in a slab page can belong to differe

mm: vmstat: add some comments on internal storage of byte items

Byte-accounted items are used for slab object accounting at the cgroup
level, because the objects in a slab page can belong to different cgroups.
At the global level these items always change in multiples of whole slab
pages. The vmstat code exploits this and stores these items as pages
internally, which allows for more compact per-cpu data.

This optimization isn't self-evident from the asserts and the division in
the stat update functions. Provide the reader with some context.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: move lruvec stats update functions to vmstat.h

Patch series "memcg: add pagetable comsumption to memory.stat", v2.

Many workloads consumes significant amount of memory in pagetables. One
speci

mm: move lruvec stats update functions to vmstat.h

Patch series "memcg: add pagetable comsumption to memory.stat", v2.

Many workloads consumes significant amount of memory in pagetables. One
specific use-case is the user space network driver which mmaps the
application memory to provide zero copy transfer. This driver can consume
a large amount memory in page tables. This patch series exposes the
pagetable comsumption for each memory cgroup.

This patch (of 2):

This does not change any functionality and only move the functions which
update the lruvec stats to vmstat.h from memcontrol.h. The main reason
for this patch is to be able to use these functions in the page table
contructor function which is defined in mm.h and we can not include the
memcontrol.h in that file. Also this is a better place for this interface
in general. The lruvec abstraction, while invented for memcg, isn't
specific to memcg at all.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Shakeel Butt <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Roman Gushchin <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: use self-explanatory macros rather than "2"

Signed-off-by: Yu Zhao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Alex Shi <[email protected]>
Link: ht

mm: use self-explanatory macros rather than "2"

Signed-off-by: Yu Zhao <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Alex Shi <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

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mm: memcg/slab: fix slab statistics in !SMP configuration

Since commit ea426c2a7de8 ("mm: memcg: prepare for byte-sized vmstat
items") the write side of slab counters accepts a value in bytes and
co

mm: memcg/slab: fix slab statistics in !SMP configuration

Since commit ea426c2a7de8 ("mm: memcg: prepare for byte-sized vmstat
items") the write side of slab counters accepts a value in bytes and
converts it to pages. It happens in __mod_node_page_state().

However a non-SMP version of __mod_node_page_state() doesn't perform
this conversion. It leads to incorrect (unrealistically high) slab
counters values. Fix this by adding a similar conversion to the non-SMP
version of __mod_node_page_state().

Signed-off-by: Roman Gushchin <[email protected]>
Reported-and-tested-by: Bastian Bittorf <[email protected]>
Fixes: ea426c2a7de8 ("mm: memcg: prepare for byte-sized vmstat items")
Acked-by: Vlastimil Babka <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: memcg: prepare for byte-sized vmstat items

To implement per-object slab memory accounting, we need to convert slab
vmstat counters to bytes. Actually, out of 4 levels of counters: global,
per-n

mm: memcg: prepare for byte-sized vmstat items

To implement per-object slab memory accounting, we need to convert slab
vmstat counters to bytes. Actually, out of 4 levels of counters: global,
per-node, per-memcg and per-lruvec only two last levels will require
byte-sized counters. It's because global and per-node counters will be
counting the number of slab pages, and per-memcg and per-lruvec will be
counting the amount of memory taken by charged slab objects.

Converting all vmstat counters to bytes or even all slab counters to bytes
would introduce an additional overhead. So instead let's store global and
per-node counters in pages, and memcg and lruvec counters in bytes.

To make the API clean all access helpers (both on the read and write
sides) are dealing with bytes.

To avoid back-and-forth conversions a new flavor of read-side helpers is
introduced, which always returns values in pages: node_page_state_pages()
and global_node_page_state_pages().

Actually new helpers are just reading raw values. Old helpers are simple
wrappers, which will complain on an attempt to read byte value, because at
the moment no one actually needs bytes.

Thanks to Johannes Weiner for the idea of having the byte-sized API on top
of the page-sized internal storage.

Signed-off-by: Roman Gushchin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Vlastimil Babka <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Tejun Heo <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

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