07 Sep, 2017
1 commit
-
Several functions use an enum type as parameter for an event/state, but
are called in some locations with an argument of a different enum type.
Adjust the interface of these functions to reality by changing the
parameter to int.This fixes a ton of enum-conversion warnings that are generated when
building the kernel with clang.[mka@chromium.org: also change parameter type of inc/dec/mod_memcg_page_state()]
Link: http://lkml.kernel.org/r/20170728213442.93823-1-mka@chromium.org
Link: http://lkml.kernel.org/r/20170727211004.34435-1-mka@chromium.org
Signed-off-by: Matthias Kaehlcke
Acked-by: Johannes Weiner
Acked-by: Michal Hocko
Cc: Vladimir Davydov
Cc: Doug Anderson
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
19 Aug, 2017
1 commit
-
Jaegeuk and Brad report a NULL pointer crash when writeback ending tries
to update the memcg stats:BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0
IP: test_clear_page_writeback+0x12e/0x2c0
[...]
RIP: 0010:test_clear_page_writeback+0x12e/0x2c0
Call Trace:
end_page_writeback+0x47/0x70
f2fs_write_end_io+0x76/0x180 [f2fs]
bio_endio+0x9f/0x120
blk_update_request+0xa8/0x2f0
scsi_end_request+0x39/0x1d0
scsi_io_completion+0x211/0x690
scsi_finish_command+0xd9/0x120
scsi_softirq_done+0x127/0x150
__blk_mq_complete_request_remote+0x13/0x20
flush_smp_call_function_queue+0x56/0x110
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x27/0x40
call_function_single_interrupt+0x89/0x90
RIP: 0010:native_safe_halt+0x6/0x10(gdb) l *(test_clear_page_writeback+0x12e)
0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619).
614 mod_node_page_state(page_pgdat(page), idx, val);
615 if (mem_cgroup_disabled() || !page->mem_cgroup)
616 return;
617 mod_memcg_state(page->mem_cgroup, idx, val);
618 pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
619 this_cpu_add(pn->lruvec_stat->count[idx], val);
620 }
621
622 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
623 gfp_t gfp_mask,The issue is that writeback doesn't hold a page reference and the page
might get freed after PG_writeback is cleared (and the mapping is
unlocked) in test_clear_page_writeback(). The stat functions looking up
the page's node or zone are safe, as those attributes are static across
allocation and free cycles. But page->mem_cgroup is not, and it will
get cleared if we race with truncation or migration.It appears this race window has been around for a while, but less likely
to trigger when the memcg stats were updated first thing after
PG_writeback is cleared. Recent changes reshuffled this code to update
the global node stats before the memcg ones, though, stretching the race
window out to an extent where people can reproduce the problem.Update test_clear_page_writeback() to look up and pin page->mem_cgroup
before clearing PG_writeback, then not use that pointer afterward. It
is a partial revert of 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
but leaves the pageref-holding callsites that aren't affected alone.Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org
Fixes: 62cccb8c8e7a ("mm: simplify lock_page_memcg()")
Signed-off-by: Johannes Weiner
Reported-by: Jaegeuk Kim
Tested-by: Jaegeuk Kim
Reported-by: Bradley Bolen
Tested-by: Brad Bolen
Cc: Vladimir Davydov
Cc: Michal Hocko
Cc: [4.6+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Jul, 2017
5 commits
-
lruvecs are at the intersection of the NUMA node and memcg, which is the
scope for most paging activity.Introduce a convenient accounting infrastructure that maintains
statistics per node, per memcg, and the lruvec itself.Then convert over accounting sites for statistics that are already
tracked in both nodes and memcgs and can be easily switched.[hannes@cmpxchg.org: fix crash in the new cgroup stat keeping code]
Link: http://lkml.kernel.org/r/20170531171450.GA10481@cmpxchg.org
[hannes@cmpxchg.org: don't track uncharged pages at all
Link: http://lkml.kernel.org/r/20170605175254.GA8547@cmpxchg.org
[hannes@cmpxchg.org: add missing free_percpu()]
Link: http://lkml.kernel.org/r/20170605175354.GB8547@cmpxchg.org
[linux@roeck-us.net: hexagon: fix build error caused by include file order]
Link: http://lkml.kernel.org/r/20170617153721.GA4382@roeck-us.net
Link: http://lkml.kernel.org/r/20170530181724.27197-6-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Signed-off-by: Guenter Roeck
Acked-by: Vladimir Davydov
Cc: Josef Bacik
Cc: Michal Hocko
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The kmem-specific functions do the same thing. Switch and drop.
Link: http://lkml.kernel.org/r/20170530181724.27197-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Josef Bacik
Cc: Michal Hocko
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that the slab counters are moved from the zone to the node level we
can drop the private memcg node stats and use the official ones.Link: http://lkml.kernel.org/r/20170530181724.27197-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Josef Bacik
Cc: Michal Hocko
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Show count of oom killer invocations in /proc/vmstat and count of
processes killed in memory cgroup in knob "memory.events" (in
memory.oom_control for v1 cgroup).Also describe difference between "oom" and "oom_kill" in memory cgroup
documentation. Currently oom in memory cgroup kills tasks iff shortage
has happened inside page fault.These counters helps in monitoring oom kills - for now the only way is
grepping for magic words in kernel log.[akpm@linux-foundation.org: fix for mem_cgroup_count_vm_event() rename]
[akpm@linux-foundation.org: fix comment, per Konstantin]
Link: http://lkml.kernel.org/r/149570810989.203600.9492483715840752937.stgit@buzz
Signed-off-by: Konstantin Khlebnikov
Cc: Michal Hocko
Cc: Tetsuo Handa
Cc: Roman Guschin
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Track the following reclaim counters for every memory cgroup: PGREFILL,
PGSCAN, PGSTEAL, PGACTIVATE, PGDEACTIVATE, PGLAZYFREE and PGLAZYFREED.These values are exposed using the memory.stats interface of cgroup v2.
The meaning of each value is the same as for global counters, available
using /proc/vmstat.Also, for consistency, rename mem_cgroup_count_vm_event() to
count_memcg_event_mm().Link: http://lkml.kernel.org/r/1494530183-30808-1-git-send-email-guro@fb.com
Signed-off-by: Roman Gushchin
Suggested-by: Johannes Weiner
Acked-by: Michal Hocko
Acked-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Tejun Heo
Cc: Li Zefan
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 May, 2017
6 commits
-
The memory controllers stat function names are awkwardly long and
arbitrarily different from the zone and node stat functions.The current interface is named:
mem_cgroup_read_stat()
mem_cgroup_update_stat()
mem_cgroup_inc_stat()
mem_cgroup_dec_stat()
mem_cgroup_update_page_stat()
mem_cgroup_inc_page_stat()
mem_cgroup_dec_page_stat()This patch renames it to match the corresponding node stat functions:
memcg_page_state() [node_page_state()]
mod_memcg_state() [mod_node_state()]
inc_memcg_state() [inc_node_state()]
dec_memcg_state() [dec_node_state()]
mod_memcg_page_state() [mod_node_page_state()]
inc_memcg_page_state() [inc_node_page_state()]
dec_memcg_page_state() [dec_node_page_state()]Link: http://lkml.kernel.org/r/20170404220148.28338-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The current duplication is a high-maintenance mess, and it's painful to
add new items or query memcg state from the rest of the VM.This increases the size of the stat array marginally, but we should aim
to track all these stats on a per-cgroup level anyway.Link: http://lkml.kernel.org/r/20170404220148.28338-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The current duplication is a high-maintenance mess, and it's painful to
add new items.This increases the size of the event array, but we'll eventually want
most of the VM events tracked on a per-cgroup basis anyway.Link: http://lkml.kernel.org/r/20170404220148.28338-2-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We only ever count single events, drop the @nr parameter. Rename the
function accordingly. Remove low-information kerneldoc.Link: http://lkml.kernel.org/r/20170404220148.28338-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since commit 59dc76b0d4df ("mm: vmscan: reduce size of inactive file
list") we noticed bigger IO spikes during changes in cache access
patterns.The patch in question shrunk the inactive list size to leave more room
for the current workingset in the presence of streaming IO. However,
workingset transitions that previously happened on the inactive list are
now pushed out of memory and incur more refaults to complete.This patch disables active list protection when refaults are being
observed. This accelerates workingset transitions, and allows more of
the new set to establish itself from memory, without eating into the
ability to protect the established workingset during stable periods.The workloads that were measurably affected for us were hit pretty bad
by it, with refault/majfault rates doubling and tripling during cache
transitions, and the machines sustaining half-hour periods of 100% IO
utilization, where they'd previously have sub-minute peaks at 60-90%.Stateful services that handle user data tend to be more conservative
with kernel upgrades. As a result we hit most page cache issues with
some delay, as was the case here.The severity seemed to warrant a stable tag.
Fixes: 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list")
Link: http://lkml.kernel.org/r/20170404220052.27593-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Cc: Rik van Riel
Cc: Mel Gorman
Cc: Michal Hocko
Cc: Vladimir Davydov
Cc: [4.7+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Cgroups currently don't report how much shmem they use, which can be
useful data to have, in particular since shmem is included in the
cache/file item while being reclaimed like anonymous memory.Add a counter to track shmem pages during charging and uncharging.
Link: http://lkml.kernel.org/r/20170221164343.32252-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Reported-by: Chris Down
Cc: Michal Hocko
Cc: Vladimir Davydov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Apr, 2017
1 commit
-
Huge pages are accounted as single units in the memcg's "file_mapped"
counter. Account the correct number of base pages, like we do in the
corresponding node counter.Link: http://lkml.kernel.org/r/20170322005111.3156-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Reviewed-by: Kirill A. Shutemov
Acked-by: Michal Hocko
Cc: Vladimir Davydov
Cc: [4.8+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Feb, 2017
2 commits
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If there's contention on slab_mutex, queueing the per-cache destruction
work item on the system_wq can unnecessarily create and tie up a lot of
kworkers.Rename memcg_kmem_cache_create_wq to memcg_kmem_cache_wq and make it
global and use that workqueue for the destruction work items too. While
at it, convert the workqueue from an unbound workqueue to a per-cpu one
with concurrency limited to 1. It's generally preferable to use per-cpu
workqueues and concurrency limit of 1 is safe enough.This is suggested by Joonsoo Kim.
Link: http://lkml.kernel.org/r/20170117235411.9408-11-tj@kernel.org
Signed-off-by: Tejun Heo
Reported-by: Jay Vana
Acked-by: Vladimir Davydov
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
With kmem cgroup support enabled, kmem_caches can be created and
destroyed frequently and a great number of near empty kmem_caches can
accumulate if there are a lot of transient cgroups and the system is not
under memory pressure. When memory reclaim starts under such
conditions, it can lead to consecutive deactivation and destruction of
many kmem_caches, easily hundreds of thousands on moderately large
systems, exposing scalability issues in the current slab management
code. This is one of the patches to address the issue.While a memcg kmem_cache is listed on its root cache's ->children list,
there is no direct way to iterate all kmem_caches which are assocaited
with a memory cgroup. The only way to iterate them is walking all
caches while filtering out caches which don't match, which would be most
of them.This makes memcg destruction operations O(N^2) where N is the total
number of slab caches which can be huge. This combined with the
synchronous RCU operations can tie up a CPU and affect the whole machine
for many hours when memory reclaim triggers offlining and destruction of
the stale memcgs.This patch adds mem_cgroup->kmem_caches list which goes through
memcg_cache_params->kmem_caches_node of all kmem_caches which are
associated with the memcg. All memcg specific iterations, including
stat file access, are updated to use the new list instead.Link: http://lkml.kernel.org/r/20170117235411.9408-6-tj@kernel.org
Signed-off-by: Tejun Heo
Reported-by: Jay Vana
Acked-by: Vladimir Davydov
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Jan, 2017
1 commit
-
Nils Holland and Klaus Ethgen have reported unexpected OOM killer
invocations with 32b kernel starting with 4.8 kernelskworker/u4:5 invoked oom-killer: gfp_mask=0x2400840(GFP_NOFS|__GFP_NOFAIL), nodemask=0, order=0, oom_score_adj=0
kworker/u4:5 cpuset=/ mems_allowed=0
CPU: 1 PID: 2603 Comm: kworker/u4:5 Not tainted 4.9.0-gentoo #2
[...]
Mem-Info:
active_anon:58685 inactive_anon:90 isolated_anon:0
active_file:274324 inactive_file:281962 isolated_file:0
unevictable:0 dirty:649 writeback:0 unstable:0
slab_reclaimable:40662 slab_unreclaimable:17754
mapped:7382 shmem:202 pagetables:351 bounce:0
free:206736 free_pcp:332 free_cma:0
Node 0 active_anon:234740kB inactive_anon:360kB active_file:1097296kB inactive_file:1127848kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:29528kB dirty:2596kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 184320kB anon_thp: 808kB writeback_tmp:0kB unstable:0kB pages_scanned:0 all_unreclaimable? no
DMA free:3952kB min:788kB low:984kB high:1180kB active_anon:0kB inactive_anon:0kB active_file:7316kB inactive_file:0kB unevictable:0kB writepending:96kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:3200kB slab_unreclaimable:1408kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
lowmem_reserve[]: 0 813 3474 3474
Normal free:41332kB min:41368kB low:51708kB high:62048kB active_anon:0kB inactive_anon:0kB active_file:532748kB inactive_file:44kB unevictable:0kB writepending:24kB present:897016kB managed:836248kB mlocked:0kB slab_reclaimable:159448kB slab_unreclaimable:69608kB kernel_stack:1112kB pagetables:1404kB bounce:0kB free_pcp:528kB local_pcp:340kB free_cma:0kB
lowmem_reserve[]: 0 0 21292 21292
HighMem free:781660kB min:512kB low:34356kB high:68200kB active_anon:234740kB inactive_anon:360kB active_file:557232kB inactive_file:1127804kB unevictable:0kB writepending:2592kB present:2725384kB managed:2725384kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:800kB local_pcp:608kB free_cma:0kBthe oom killer is clearly pre-mature because there there is still a lot
of page cache in the zone Normal which should satisfy this lowmem
request. Further debugging has shown that the reclaim cannot make any
forward progress because the page cache is hidden in the active list
which doesn't get rotated because inactive_list_is_low is not memcg
aware.The code simply subtracts per-zone highmem counters from the respective
memcg's lru sizes which doesn't make any sense. We can simply end up
always seeing the resulting active and inactive counts 0 and return
false. This issue is not limited to 32b kernels but in practice the
effect on systems without CONFIG_HIGHMEM would be much harder to notice
because we do not invoke the OOM killer for allocations requests
targeting < ZONE_NORMAL.Fix the issue by tracking per zone lru page counts in mem_cgroup_per_node
and subtract per-memcg highmem counts when memcg is enabled. Introduce
helper lruvec_zone_lru_size which redirects to either zone counters or
mem_cgroup_get_zone_lru_size when appropriate.We are losing empty LRU but non-zero lru size detection introduced by
ca707239e8a7 ("mm: update_lru_size warn and reset bad lru_size") because
of the inherent zone vs. node discrepancy.Fixes: f8d1a31163fc ("mm: consider whether to decivate based on eligible zones inactive ratio")
Link: http://lkml.kernel.org/r/20170104100825.3729-1-mhocko@kernel.org
Signed-off-by: Michal Hocko
Reported-by: Nils Holland
Tested-by: Nils Holland
Reported-by: Klaus Ethgen
Acked-by: Minchan Kim
Acked-by: Mel Gorman
Acked-by: Johannes Weiner
Reviewed-by: Vladimir Davydov
Cc: [4.8+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Oct, 2016
2 commits
-
The cgroup core and the memory controller need to track socket ownership
for different purposes, but the tracking sites being entirely different
is kind of ugly.Be a better citizen and rename the memory controller callbacks to match
the cgroup core callbacks, then move them to the same place.[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20160914194846.11153-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner
Acked-by: Tejun Heo
Cc: "David S. Miller"
Cc: Michal Hocko
Cc: Vladimir Davydov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When selecting an oom victim, we use the same heuristic for both memory
cgroup and global oom. The only difference is the scope of tasks to
select the victim from. So we could just export an iterator over all
memcg tasks and keep all oom related logic in oom_kill.c, but instead we
duplicate pieces of it in memcontrol.c reusing some initially private
functions of oom_kill.c in order to not duplicate all of it. That looks
ugly and error prone, because any modification of select_bad_process
should also be propagated to mem_cgroup_out_of_memory.Let's rework this as follows: keep all oom heuristic related code private
to oom_kill.c and make oom_kill.c use exported memcg functions when it's
really necessary (like in case of iterating over memcg tasks).Link: http://lkml.kernel.org/r/1470056933-7505-1-git-send-email-vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Cc: Tetsuo Handa
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Jul, 2016
6 commits
-
We should account for stacks regardless of stack size, and we need to
account in sub-page units if THREAD_SIZE < PAGE_SIZE. Change the units
to kilobytes and Move it into account_kernel_stack().Fixes: 12580e4b54ba8 ("mm: memcontrol: report kernel stack usage in cgroup2 memory.stat")
Link: http://lkml.kernel.org/r/9b5314e3ee5eda61b0317ec1563768602c1ef438.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski
Cc: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Reviewed-by: Josh Poimboeuf
Reviewed-by: Vladimir Davydov
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Minchan Kim reported setting the following warning on a 32-bit system
although it can affect 64-bit systems.WARNING: CPU: 4 PID: 1322 at mm/memcontrol.c:998 mem_cgroup_update_lru_size+0x103/0x110
mem_cgroup_update_lru_size(f44b4000, 1, -7): zid 1 lru_size 1 but empty
Modules linked in:
CPU: 4 PID: 1322 Comm: cp Not tainted 4.7.0-rc4-mm1+ #143
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x76/0xaf
__warn+0xea/0x110
? mem_cgroup_update_lru_size+0x103/0x110
warn_slowpath_fmt+0x3b/0x40
mem_cgroup_update_lru_size+0x103/0x110
isolate_lru_pages.isra.61+0x2e2/0x360
shrink_active_list+0xac/0x2a0
? __delay+0xe/0x10
shrink_node_memcg+0x53c/0x7a0
shrink_node+0xab/0x2a0
do_try_to_free_pages+0xc6/0x390
try_to_free_pages+0x245/0x590LRU list contents and counts are updated separately. Counts are updated
before pages are added to the LRU and updated after pages are removed.
The warning above is from a check in mem_cgroup_update_lru_size that
ensures that list sizes of zero are empty.The problem is that node-lru needs to account for highmem pages if
CONFIG_HIGHMEM is set. One impact of the implementation is that the
sizes are updated in multiple passes when pages from multiple zones were
isolated. This happens whether HIGHMEM is set or not. When multiple
zones are isolated, it's possible for a debugging check in memcg to be
tripped.This patch forces all the zone counts to be updated before the memcg
function is called.Link: http://lkml.kernel.org/r/1468588165-12461-6-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Tested-by: Minchan Kim
Reported-by: Minchan Kim
Acked-by: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Memcg needs adjustment after moving LRUs to the node. Limits are
tracked per memcg but the soft-limit excess is tracked per zone. As
global page reclaim is based on the node, it is easy to imagine a
situation where a zone soft limit is exceeded even though the memcg
limit is fine.This patch moves the soft limit tree the node. Technically, all the
variable names should also change but people are already familiar by the
meaning of "mz" even if "mn" would be a more appropriate name now.Link: http://lkml.kernel.org/r/1467970510-21195-15-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Michal Hocko
Cc: Hillf Danton
Acked-by: Johannes Weiner
Cc: Joonsoo Kim
Cc: Minchan Kim
Cc: Rik van Riel
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Earlier patches focused on having direct reclaim and kswapd use data
that is node-centric for reclaiming but shrink_node() itself still uses
too much zone information. This patch removes unnecessary zone-based
information with the most important decision being whether to continue
reclaim or not. Some memcg APIs are adjusted as a result even though
memcg itself still uses some zone information.[mgorman@techsingularity.net: optimization]
Link: http://lkml.kernel.org/r/1468588165-12461-2-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-14-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Michal Hocko
Acked-by: Vlastimil Babka
Cc: Hillf Danton
Acked-by: Johannes Weiner
Cc: Joonsoo Kim
Cc: Minchan Kim
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This moves the LRU lists from the zone to the node and related data such
as counters, tracing, congestion tracking and writeback tracking.Unfortunately, due to reclaim and compaction retry logic, it is
necessary to account for the number of LRU pages on both zone and node
logic. Most reclaim logic is based on the node counters but the retry
logic uses the zone counters which do not distinguish inactive and
active sizes. It would be possible to leave the LRU counters on a
per-zone basis but it's a heavier calculation across multiple cache
lines that is much more frequent than the retry checks.Other than the LRU counters, this is mostly a mechanical patch but note
that it introduces a number of anomalies. For example, the scans are
per-zone but using per-node counters. We also mark a node as congested
when a zone is congested. This causes weird problems that are fixed
later but is easier to review.In the event that there is excessive overhead on 32-bit systems due to
the nodes being on LRU then there are two potential solutions1. Long-term isolation of highmem pages when reclaim is lowmem
When pages are skipped, they are immediately added back onto the LRU
list. If lowmem reclaim persisted for long periods of time, the same
highmem pages get continually scanned. The idea would be that lowmem
keeps those pages on a separate list until a reclaim for highmem pages
arrives that splices the highmem pages back onto the LRU. It potentially
could be implemented similar to the UNEVICTABLE list.That would reduce the skip rate with the potential corner case is that
highmem pages have to be scanned and reclaimed to free lowmem slab pages.2. Linear scan lowmem pages if the initial LRU shrink fails
This will break LRU ordering but may be preferable and faster during
memory pressure than skipping LRU pages.Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman
Acked-by: Johannes Weiner
Acked-by: Vlastimil Babka
Cc: Hillf Danton
Cc: Joonsoo Kim
Cc: Michal Hocko
Cc: Minchan Kim
Cc: Rik van Riel
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Commit 23047a96d7cf ("mm: workingset: per-cgroup cache thrash
detection") added a page->mem_cgroup lookup to the cache eviction,
refault, and activation paths, as well as locking to the activation
path, and the vm-scalability tests showed a regression of -23%.While the test in question is an artificial worst-case scenario that
doesn't occur in real workloads - reading two sparse files in parallel
at full CPU speed just to hammer the LRU paths - there is still some
optimizations that can be done in those paths.Inline the lookup functions to eliminate calls. Also, page->mem_cgroup
doesn't need to be stabilized when counting an activation; we merely
need to hold the RCU lock to prevent the memcg from being freed.This cuts down on overhead quite a bit:
23047a96d7cfcfca 063f6715e77a7be5770d6081fe
---------------- --------------------------
%stddev %change %stddev
\ | \
21621405 +- 0% +11.3% 24069657 +- 2% vm-scalability.throughput[linux@roeck-us.net: drop unnecessary include file]
[hannes@cmpxchg.org: add WARN_ON_ONCE()s]
Link: http://lkml.kernel.org/r/20160707194024.GA26580@cmpxchg.org
Link: http://lkml.kernel.org/r/20160624175101.GA3024@cmpxchg.org
Reported-by: Ye Xiaolong
Signed-off-by: Johannes Weiner
Acked-by: Michal Hocko
Cc: Vladimir Davydov
Signed-off-by: Guenter Roeck
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
27 Jul, 2016
1 commit
-
- Handle memcg_kmem_enabled check out to the caller. This reduces the
number of function definitions making the code easier to follow. At
the same time it doesn't result in code bloat, because all of these
functions are used only in one or two places.- Move __GFP_ACCOUNT check to the caller as well so that one wouldn't
have to dive deep into memcg implementation to see which allocations
are charged and which are not.- Refresh comments.
Link: http://lkml.kernel.org/r/52882a28b542c1979fd9a033b4dc8637fc347399.1464079537.git.vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: Eric Dumazet
Cc: Minchan Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
23 Jul, 2016
1 commit
-
The memory controller has quite a bit of state that usually outlives the
cgroup and pins its CSS until said state disappears. At the same time
it imposes a 16-bit limit on the CSS ID space to economically store IDs
in the wild. Consequently, when we use cgroups to contain frequent but
small and short-lived jobs that leave behind some page cache, we quickly
run into the 64k limitations of outstanding CSSs. Creating a new cgroup
fails with -ENOSPC while there are only a few, or even no user-visible
cgroups in existence.Although pinning CSSs past cgroup removal is common, there are only two
instances that actually need an ID after a cgroup is deleted: cache
shadow entries and swapout records.Cache shadow entries reference the ID weakly and can deal with the CSS
having disappeared when it's looked up later. They pose no hurdle.Swap-out records do need to pin the css to hierarchically attribute
swapins after the cgroup has been deleted; though the only pages that
remain swapped out after offlining are tmpfs/shmem pages. And those
references are under the user's control, so they are manageable.This patch introduces a private 16-bit memcg ID and switches swap and
cache shadow entries over to using that. This ID can then be recycled
after offlining when the CSS remains pinned only by objects that don't
specifically need it.This script demonstrates the problem by faulting one cache page in a new
cgroup and deleting it again:set -e
mkdir -p pages
for x in `seq 128000`; do
[ $((x % 1000)) -eq 0 ] && echo $x
mkdir /cgroup/foo
echo $$ >/cgroup/foo/cgroup.procs
echo trex >pages/$x
echo $$ >/cgroup/cgroup.procs
rmdir /cgroup/foo
doneWhen run on an unpatched kernel, we eventually run out of possible IDs
even though there are no visible cgroups:[root@ham ~]# ./cssidstress.sh
[...]
65000
mkdir: cannot create directory '/cgroup/foo': No space left on deviceAfter this patch, the IDs get released upon cgroup destruction and the
cache and css objects get released once memory reclaim kicks in.[hannes@cmpxchg.org: init the IDR]
Link: http://lkml.kernel.org/r/20160621154601.GA22431@cmpxchg.org
Fixes: b2052564e66d ("mm: memcontrol: continue cache reclaim from offlined groups")
Link: http://lkml.kernel.org/r/20160617162516.GD19084@cmpxchg.org
Signed-off-by: Johannes Weiner
Reported-by: John Garcia
Reviewed-by: Vladimir Davydov
Acked-by: Tejun Heo
Cc: Nikolay Borisov
Cc: [3.19+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 May, 2016
1 commit
-
The inactive file list should still be large enough to contain readahead
windows and freshly written file data, but it no longer is the only
source for detecting multiple accesses to file pages. The workingset
refault measurement code causes recently evicted file pages that get
accessed again after a shorter interval to be promoted directly to the
active list.With that mechanism in place, we can afford to (on a larger system)
dedicate more memory to the active file list, so we can actually cache
more of the frequently used file pages in memory, and not have them
pushed out by streaming writes, once-used streaming file reads, etc.This can help things like database workloads, where only half the page
cache can currently be used to cache the database working set. This
patch automatically increases that fraction on larger systems, using the
same ratio that has already been used for anonymous memory.[hannes@cmpxchg.org: cgroup-awareness]
Signed-off-by: Rik van Riel
Signed-off-by: Johannes Weiner
Reported-by: Andres Freund
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 May, 2016
1 commit
-
Konstantin Khlebnikov pointed out (nearly four years ago, when lumpy
reclaim was removed) that lru_size can be updated by -nr_taken once per
call to isolate_lru_pages(), instead of page by page.Update it inside isolate_lru_pages(), or at its two callsites? I chose
to update it at the callsites, rearranging and grouping the updates by
nr_taken and nr_scanned together in both.With one exception, mem_cgroup_update_lru_size(,lru,) is then used where
__mod_zone_page_state(,NR_LRU_BASE+lru,) is used; and we shall be adding
some more calls in a future commit. Make the code a little smaller and
simpler by incorporating stat update in lru_size update.The exception was move_active_pages_to_lru(), which aggregated the
pgmoved stat update separately from the individual lru_size updates; but
I still think this a simplification worth making.However, the __mod_zone_page_state is not peculiar to mem_cgroups: so
better use the name update_lru_size, calls mem_cgroup_update_lru_size
when CONFIG_MEMCG.Signed-off-by: Hugh Dickins
Cc: "Kirill A. Shutemov"
Cc: Andrea Arcangeli
Cc: Andres Lagar-Cavilla
Cc: Yang Shi
Cc: Ning Qu
Cc: Mel Gorman
Cc: Konstantin Khlebnikov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Mar, 2016
4 commits
-
Workingset code was recently made memcg aware, but shadow node shrinker
is still global. As a result, one small cgroup can consume all memory
available for shadow nodes, possibly hurting other cgroups by reclaiming
their shadow nodes, even though reclaim distances stored in its shadow
nodes have no effect. To avoid this, we need to make shadow node
shrinker memcg aware.Signed-off-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
As kmem accounting is now either enabled for all cgroups or disabled
system-wide, there's no point in having memcg_kmem_online() helper -
instead one can use memcg_kmem_enabled() and mem_cgroup_online(), as
shrink_slab() now does.There are only two places left where this helper is used -
__memcg_kmem_charge() and memcg_create_kmem_cache(). The former can
only be called if memcg_kmem_enabled() returned true. Since the cgroup
it operates on is online, mem_cgroup_is_root() check will be enough.memcg_create_kmem_cache() can't use mem_cgroup_online() helper instead
of memcg_kmem_online(), because it relies on the fact that in
memcg_offline_kmem() memcg->kmem_state is changed before
memcg_deactivate_kmem_caches() is called, but there we can just
open-code the check.Signed-off-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Show how much memory is allocated to kernel stacks.
Signed-off-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Show how much memory is used for storing reclaimable and unreclaimable
in-kernel data structures allocated from slab caches.Signed-off-by: Vladimir Davydov
Acked-by: Johannes Weiner
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
16 Mar, 2016
6 commits
-
There are several users that nest lock_page_memcg() inside lock_page()
to prevent page->mem_cgroup from changing. But the page lock prevents
pages from moving between cgroups, so that is unnecessary overhead.Remove lock_page_memcg() in contexts with locked contexts and fix the
debug code in the page stat functions to be okay with the page lock.Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Now that migration doesn't clear page->mem_cgroup of live pages anymore,
it's safe to make lock_page_memcg() and the memcg stat functions take
pages, and spare the callers from memcg objects.[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Johannes Weiner
Suggested-by: Vladimir Davydov
Acked-by: Vladimir Davydov
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Changing a page's memcg association complicates dealing with the page,
so we want to limit this as much as possible. Page migration e.g. does
not have to do that. Just like page cache replacement, it can forcibly
charge a replacement page, and then uncharge the old page when it gets
freed. Temporarily overcharging the cgroup by a single page is not an
issue in practice, and charging is so cheap nowadays that this is much
preferrable to the headache of messing with live pages.The only place that still changes the page->mem_cgroup binding of live
pages is when pages move along with a task to another cgroup. But that
path isolates the page from the LRU, takes the page lock, and the move
lock (lock_page_memcg()). That means page->mem_cgroup is always stable
in callers that have the page isolated from the LRU or locked. Lighter
unlocked paths, like writeback accounting, can use lock_page_memcg().[akpm@linux-foundation.org: fix build]
[vdavydov@virtuozzo.com: fix lockdep splat]
Signed-off-by: Johannes Weiner
Acked-by: Vladimir Davydov
Cc: Johannes Weiner
Cc: Michal Hocko
Cc: Greg Thelen
Cc: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Cache thrash detection (see a528910e12ec "mm: thrash detection-based
file cache sizing" for details) currently only works on the system
level, not inside cgroups. Worse, as the refaults are compared to the
global number of active cache, cgroups might wrongfully get all their
refaults activated when their pages are hotter than those of others.Move the refault machinery from the zone to the lruvec, and then tag
eviction entries with the memcg ID. This makes the thrash detection
work correctly inside cgroups.[sergey.senozhatsky@gmail.com: do not return from workingset_activation() with locked rcu and page]
Signed-off-by: Johannes Weiner
Signed-off-by: Sergey Senozhatsky
Reviewed-by: Vladimir Davydov
Cc: Michal Hocko
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These patches tag the page cache radix tree eviction entries with the
memcg an evicted page belonged to, thus making per-cgroup LRU reclaim
work properly and be as adaptive to new cache workingsets as global
reclaim already is.This should have been part of the original thrash detection patch
series, but was deferred due to the complexity of those patches.This patch (of 5):
So far the only sites that needed to exclude charge migration to
stabilize page->mem_cgroup have been per-cgroup page statistics, hence
the name mem_cgroup_begin_page_stat(). But per-cgroup thrash detection
will add another site that needs to ensure page->mem_cgroup lifetime.Rename these locking functions to the more generic lock_page_memcg() and
unlock_page_memcg(). Since charge migration is a cgroup1 feature only,
we might be able to delete it at some point, and these now easy to
identify locking sites along with it.Signed-off-by: Johannes Weiner
Suggested-by: Vladimir Davydov
Acked-by: Vladimir Davydov
Cc: Michal Hocko
Cc: David Rientjes
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix up trivial spelling errors, noticed while reading the code.
Signed-off-by: Jesper Dangaard Brouer
Cc: Christoph Lameter
Cc: Pekka Enberg
Cc: David Rientjes
Cc: Joonsoo Kim
Cc: Vladimir Davydov
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Feb, 2016
1 commit
-
MEM_CGROUP_STAT_NSTATS is just a delimiter for cgroup1 statistics, not
an actual array entry. Reuse it for the first cgroup2 stat entry, like
in the event array.Fixes: b2807f07f4f8 ("mm: memcontrol: add "sock" to cgroup2 memory.stat")
Signed-off-by: Johannes Weiner
Cc: Vladimir Davydov
Cc: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds