ef62c8ff1d
Patch series "mm/page_owner: Extend page_owner to show memcg information", v4.
While debugging the constant increase in percpu memory consumption on a
system that spawned large number of containers, it was found that a lot
of offline mem_cgroup structures remained in place without being freed.
Further investigation indicated that those mem_cgroup structures were
pinned by some pages.
In order to find out what those pages are, the existing page_owner
debugging tool is extended to show memory cgroup information and whether
those memcgs are offline or not. With the enhanced page_owner tool, the
following is a typical page that pinned the mem_cgroup structure in my
test case:
Page allocated via order 0, mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 162970 (podman), ts 1097761405537 ns, free_ts 1097760838089 ns
PFN 1925700 type Movable Block 3761 type Movable Flags 0x17ffffc00c001c(uptodate|dirty|lru|reclaim|swapbacked|node=0|zone=2|lastcpupid=0x1fffff)
prep_new_page+0xac/0xe0
get_page_from_freelist+0x1327/0x14d0
__alloc_pages+0x191/0x340
alloc_pages_vma+0x84/0x250
shmem_alloc_page+0x3f/0x90
shmem_alloc_and_acct_page+0x76/0x1c0
shmem_getpage_gfp+0x281/0x940
shmem_write_begin+0x36/0xe0
generic_perform_write+0xed/0x1d0
__generic_file_write_iter+0xdc/0x1b0
generic_file_write_iter+0x5d/0xb0
new_sync_write+0x11f/0x1b0
vfs_write+0x1ba/0x2a0
ksys_write+0x59/0xd0
do_syscall_64+0x37/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Charged to offline memcg libpod-conmon-15e4f9c758422306b73b2dd99f9d50a5ea53cbb16b4a13a2c2308a4253cc0ec8.
So the page was not freed because it was part of a shmem segment. That
is useful information that can help users to diagnose similar problems.
With cgroup v1, /proc/cgroups can be read to find out the total number
of memory cgroups (online + offline). With cgroup v2, the cgroup.stat
of the root cgroup can be read to find the number of dying cgroups (most
likely pinned by dying memcgs).
The page_owner feature is not supposed to be enabled for production
system due to its memory overhead. However, if it is suspected that
dying memcgs are increasing over time, a test environment with
page_owner enabled can then be set up with appropriate workload for
further analysis on what may be causing the increasing number of dying
memcgs.
This patch (of 4):
For *scnprintf(), vsnprintf() is always called even if the input size is
0. That is a waste of time, so just return 0 in this case.
Note that vsnprintf() will never return -1 to indicate an error. So
skipping the call to vsnprintf() when size is 0 will have no functional
impact at all.
Link: https://lkml.kernel.org/r/20220202203036.744010-1-longman@redhat.com
Link: https://lkml.kernel.org/r/20220202203036.744010-2-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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| .. | ||
| 842 | ||
| crypto | ||
| dim | ||
| fonts | ||
| kunit | ||
| livepatch | ||
| lz4 | ||
| lzo | ||
| math | ||
| mpi | ||
| pldmfw | ||
| raid6 | ||
| reed_solomon | ||
| test_fortify | ||
| vdso | ||
| xz | ||
| zlib_deflate | ||
| zlib_dfltcc | ||
| zlib_inflate | ||
| zstd | ||
| .gitignore | ||
| Kconfig | ||
| Kconfig.debug | ||
| Kconfig.kasan | ||
| Kconfig.kcsan | ||
| Kconfig.kfence | ||
| Kconfig.kgdb | ||
| Kconfig.ubsan | ||
| Makefile | ||
| argv_split.c | ||
| ashldi3.c | ||
| ashrdi3.c | ||
| asn1_decoder.c | ||
| asn1_encoder.c | ||
| assoc_array.c | ||
| atomic64.c | ||
| atomic64_test.c | ||
| audit.c | ||
| bcd.c | ||
| bch.c | ||
| bitfield_kunit.c | ||
| bitmap.c | ||
| bitrev.c | ||
| bootconfig.c | ||
| bsearch.c | ||
| btree.c | ||
| bucket_locks.c | ||
| bug.c | ||
| build_OID_registry | ||
| buildid.c | ||
| bust_spinlocks.c | ||
| check_signature.c | ||
| checksum.c | ||
| clz_ctz.c | ||
| clz_tab.c | ||
| cmdline.c | ||
| cmdline_kunit.c | ||
| cmpdi2.c | ||
| compat_audit.c | ||
| cpu_rmap.c | ||
| cpumask.c | ||
| crc-ccitt.c | ||
| crc-itu-t.c | ||
| crc-t10dif.c | ||
| crc4.c | ||
| crc7.c | ||
| crc8.c | ||
| crc16.c | ||
| crc32.c | ||
| crc32defs.h | ||
| crc32test.c | ||
| crc64.c | ||
| ctype.c | ||
| debug_info.c | ||
| debug_locks.c | ||
| debugobjects.c | ||
| dec_and_lock.c | ||
| decompress.c | ||
| decompress_bunzip2.c | ||
| decompress_inflate.c | ||
| decompress_unlz4.c | ||
| decompress_unlzma.c | ||
| decompress_unlzo.c | ||
| decompress_unxz.c | ||
| decompress_unzstd.c | ||
| devmem_is_allowed.c | ||
| devres.c | ||
| digsig.c | ||
| dump_stack.c | ||
| dynamic_debug.c | ||
| dynamic_queue_limits.c | ||
| earlycpio.c | ||
| errname.c | ||
| error-inject.c | ||
| errseq.c | ||
| extable.c | ||
| fault-inject-usercopy.c | ||
| fault-inject.c | ||
| fdt.c | ||
| fdt_addresses.c | ||
| fdt_empty_tree.c | ||
| fdt_ro.c | ||
| fdt_rw.c | ||
| fdt_strerror.c | ||
| fdt_sw.c | ||
| fdt_wip.c | ||
| find_bit.c | ||
| find_bit_benchmark.c | ||
| flex_proportions.c | ||
| gen_crc32table.c | ||
| gen_crc64table.c | ||
| genalloc.c | ||
| generic-radix-tree.c | ||
| glob.c | ||
| globtest.c | ||
| hexdump.c | ||
| hweight.c | ||
| idr.c | ||
| inflate.c | ||
| interval_tree.c | ||
| interval_tree_test.c | ||
| iomap.c | ||
| iomap_copy.c | ||
| iommu-helper.c | ||
| iov_iter.c | ||
| irq_poll.c | ||
| irq_regs.c | ||
| is_single_threaded.c | ||
| kasprintf.c | ||
| kfifo.c | ||
| klist.c | ||
| kobject.c | ||
| kobject_uevent.c | ||
| kstrtox.c | ||
| kstrtox.h | ||
| libcrc32c.c | ||
| linear_ranges.c | ||
| list-test.c | ||
| list_debug.c | ||
| list_sort.c | ||
| llist.c | ||
| locking-selftest-hardirq.h | ||
| locking-selftest-mutex.h | ||
| locking-selftest-rlock-hardirq.h | ||
| locking-selftest-rlock-softirq.h | ||
| locking-selftest-rlock.h | ||
| locking-selftest-rsem.h | ||
| locking-selftest-rtmutex.h | ||
| locking-selftest-softirq.h | ||
| locking-selftest-spin-hardirq.h | ||
| locking-selftest-spin-softirq.h | ||
| locking-selftest-spin.h | ||
| locking-selftest-wlock-hardirq.h | ||
| locking-selftest-wlock-softirq.h | ||
| locking-selftest-wlock.h | ||
| locking-selftest-wsem.h | ||
| locking-selftest.c | ||
| lockref.c | ||
| logic_iomem.c | ||
| logic_pio.c | ||
| lru_cache.c | ||
| lshrdi3.c | ||
| memcat_p.c | ||
| memcpy_kunit.c | ||
| memory-notifier-error-inject.c | ||
| memregion.c | ||
| memweight.c | ||
| muldi3.c | ||
| net_utils.c | ||
| netdev-notifier-error-inject.c | ||
| nlattr.c | ||
| nmi_backtrace.c | ||
| nodemask.c | ||
| notifier-error-inject.c | ||
| notifier-error-inject.h | ||
| objagg.c | ||
| of-reconfig-notifier-error-inject.c | ||
| oid_registry.c | ||
| once.c | ||
| overflow_kunit.c | ||
| packing.c | ||
| parman.c | ||
| parser.c | ||
| pci_iomap.c | ||
| percpu-refcount.c | ||
| percpu_counter.c | ||
| percpu_test.c | ||
| plist.c | ||
| pm-notifier-error-inject.c | ||
| radix-tree.c | ||
| random32.c | ||
| ratelimit.c | ||
| rbtree.c | ||
| rbtree_test.c | ||
| ref_tracker.c | ||
| refcount.c | ||
| rhashtable.c | ||
| sbitmap.c | ||
| scatterlist.c | ||
| seq_buf.c | ||
| sg_pool.c | ||
| sg_split.c | ||
| sha1.c | ||
| show_mem.c | ||
| siphash.c | ||
| slub_kunit.c | ||
| smp_processor_id.c | ||
| sort.c | ||
| stackdepot.c | ||
| stackinit_kunit.c | ||
| stmp_device.c | ||
| string.c | ||
| string_helpers.c | ||
| strncpy_from_user.c | ||
| strnlen_user.c | ||
| syscall.c | ||
| test-kstrtox.c | ||
| test-string_helpers.c | ||
| test_bitmap.c | ||
| test_bitops.c | ||
| test_bits.c | ||
| test_blackhole_dev.c | ||
| test_bpf.c | ||
| test_debug_virtual.c | ||
| test_firmware.c | ||
| test_fprobe.c | ||
| test_fpu.c | ||
| test_free_pages.c | ||
| test_hash.c | ||
| test_hexdump.c | ||
| test_hmm.c | ||
| test_hmm_uapi.h | ||
| test_ida.c | ||
| test_kasan.c | ||
| test_kasan_module.c | ||
| test_kmod.c | ||
| test_kprobes.c | ||
| test_linear_ranges.c | ||
| test_list_sort.c | ||
| test_lockup.c | ||
| test_memcat_p.c | ||
| test_meminit.c | ||
| test_min_heap.c | ||
| test_module.c | ||
| test_objagg.c | ||
| test_parman.c | ||
| test_printf.c | ||
| test_ref_tracker.c | ||
| test_rhashtable.c | ||
| test_scanf.c | ||
| test_siphash.c | ||
| test_sort.c | ||
| test_static_key_base.c | ||
| test_static_keys.c | ||
| test_string.c | ||
| test_strscpy.c | ||
| test_sysctl.c | ||
| test_ubsan.c | ||
| test_user_copy.c | ||
| test_uuid.c | ||
| test_vmalloc.c | ||
| test_xarray.c | ||
| textsearch.c | ||
| timerqueue.c | ||
| ts_bm.c | ||
| ts_fsm.c | ||
| ts_kmp.c | ||
| ubsan.c | ||
| ubsan.h | ||
| ucmpdi2.c | ||
| ucs2_string.c | ||
| usercopy.c | ||
| uuid.c | ||
| vsprintf.c | ||
| win_minmax.c | ||
| xarray.c | ||
| xxhash.c | ||