linux/mm
Kemeng Shi e32e27009f writeback: collect stats of all wb of bdi in bdi_debug_stats_show
Patch series "Improve visibility of writeback", v5.

This series tries to improve visilibity of writeback.  Patch 1 make
/sys/kernel/debug/bdi/xxx/stats show writeback info of whole bdi instead
of only writeback info in root cgroup.  Patch 2 add a new debug file
/sys/kernel/debug/bdi/xxx/wb_stats to show per wb writeback info.  Patch 3
add wb_monitor.py to monitor basic writeback info of running system, more
info could be added on demand.  Patch 4 is a random cleanup.  More details
can be found in respective patches.

Following domain hierarchy is tested:
                global domain (320G)
                /                 \
        cgroup domain1(10G)     cgroup domain2(10G)
                |                 |
bdi            wb1               wb2

/* all writeback info of bdi is successfully collected */
cat stats
BdiWriteback:             4704 kB
BdiReclaimable:        1294496 kB
BdiDirtyThresh:      204208088 kB
DirtyThresh:         195259944 kB
BackgroundThresh:     32503588 kB
BdiDirtied:           48519296 kB
BdiWritten:           47225696 kB
BdiWriteBandwidth:     1173892 kBps
b_dirty:                     1
b_io:                        0
b_more_io:                   1
b_dirty_time:                0
bdi_list:                    1
state:                       1

/* per wb writeback info of bdi is collected */
cat /sys/kernel/debug/bdi/252:16/wb_stats
WbCgIno:                    1
WbWriteback:                0 kB
WbReclaimable:              0 kB
WbDirtyThresh:              0 kB
WbDirtied:                  0 kB
WbWritten:                  0 kB
WbWriteBandwidth:      102400 kBps
b_dirty:                    0
b_io:                       0
b_more_io:                  0
b_dirty_time:               0
state:                      1

WbCgIno:                 4208
WbWriteback:            59808 kB
WbReclaimable:         676480 kB
WbDirtyThresh:        6004624 kB
WbDirtied:           23348192 kB
WbWritten:           22614592 kB
WbWriteBandwidth:      593204 kBps
b_dirty:                    1
b_io:                       1
b_more_io:                  0
b_dirty_time:               0
state:                      7

WbCgIno:                 4249
WbWriteback:           144256 kB
WbReclaimable:         432096 kB
WbDirtyThresh:        6004344 kB
WbDirtied:           25727744 kB
WbWritten:           25154752 kB
WbWriteBandwidth:      577904 kBps
b_dirty:                    0
b_io:                       1
b_more_io:                  0
b_dirty_time:               0
state:                      7

The wb_monitor.py script output is as following:
./wb_monitor.py 252:16 -c
                  writeback  reclaimable   dirtied   written    avg_bw
252:16_1                  0            0         0         0    102400
252:16_4284             672       820064   9230368   8410304    685612
252:16_4325             896       819840  10491264   9671648    652348
252:16                 1568      1639904  19721632  18081952   1440360

                  writeback  reclaimable   dirtied   written    avg_bw
252:16_1                  0            0         0         0    102400
252:16_4284             672       820064   9230368   8410304    685612
252:16_4325             896       819840  10491264   9671648    652348
252:16                 1568      1639904  19721632  18081952   1440360
...


This patch (of 5):

/sys/kernel/debug/bdi/xxx/stats is supposed to show writeback information
of whole bdi, but only writeback information of bdi in root cgroup is
collected.  So writeback information in non-root cgroup are missing now. 
To be more specific, considering following case:

/* create writeback cgroup */
cd /sys/fs/cgroup
echo "+memory +io" > cgroup.subtree_control
mkdir group1
cd group1
echo $$ > cgroup.procs
/* do writeback in cgroup */
fio -name test -filename=/dev/vdb ...
/* get writeback info of bdi */
cat /sys/kernel/debug/bdi/xxx/stats
The cat result unexpectedly implies that there is no writeback on target
bdi.

Fix this by collecting stats of all wb in bdi instead of only wb in
root cgroup.

Following domain hierarchy is tested:
                global domain (320G)
                /                 \
        cgroup domain1(10G)     cgroup domain2(10G)
                |                 |
bdi            wb1               wb2

/* all writeback info of bdi is successfully collected */
cat stats
BdiWriteback:             2912 kB
BdiReclaimable:        1598464 kB
BdiDirtyThresh:      167479028 kB
DirtyThresh:         195038532 kB
BackgroundThresh:     32466728 kB
BdiDirtied:           19141696 kB
BdiWritten:           17543456 kB
BdiWriteBandwidth:     1136172 kBps
b_dirty:                     2
b_io:                        0
b_more_io:                   1
b_dirty_time:                0
bdi_list:                    1
state:                       1

Link: https://lkml.kernel.org/r/20240423034643.141219-1-shikemeng@huaweicloud.com
Link: https://lkml.kernel.org/r/20240423034643.141219-2-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Brian Foster <bfoster@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-05 17:53:51 -07:00
..
damon mm: madvise: pageout: ignore references rather than clearing young 2024-03-04 17:01:18 -08:00
kasan fix missing vmalloc.h includes 2024-04-25 20:55:49 -07:00
kfence mm: introduce slabobj_ext to support slab object extensions 2024-04-25 20:55:51 -07:00
kmsan mm: kmsan: remove runtime checks from kmsan_unpoison_memory() 2024-02-22 10:24:41 -08:00
backing-dev.c writeback: collect stats of all wb of bdi in bdi_debug_stats_show 2024-05-05 17:53:51 -07:00
balloon_compaction.c
bootmem_info.c bootmem: use kmemleak_free_part_phys in put_page_bootmem 2023-10-25 16:47:13 -07:00
cma_debug.c
cma_sysfs.c mm/cma: add sysfs file 'release_pages_success' 2024-02-22 10:24:57 -08:00
cma.c mm/cma: drop incorrect alignment check in cma_init_reserved_mem 2024-04-25 20:56:42 -07:00
cma.h mm/cma: add sysfs file 'release_pages_success' 2024-02-22 10:24:57 -08:00
compaction.c memory: remove the now superfluous sentinel element from ctl_table array 2024-04-25 20:56:32 -07:00
debug_page_alloc.c mm: page_alloc: consolidate free page accounting 2024-04-25 20:56:04 -07:00
debug_page_ref.c
debug_vm_pgtable.c fix missing vmalloc.h includes 2024-04-25 20:55:49 -07:00
debug.c mm/debug: print only page mapcount (excluding folio entire mapcount) in __dump_folio() 2024-05-05 17:53:31 -07:00
dmapool_test.c
dmapool.c mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs 2023-12-05 11:17:58 +01:00
early_ioremap.c mm/early_ioremap.c: improve the execution efficiency of early_ioremap_setup() 2023-06-09 16:25:56 -07:00
fadvise.c mm: remove unnecessary pagevec includes 2023-06-23 16:59:31 -07:00
fail_page_alloc.c mm: page_alloc: split out FAIL_PAGE_ALLOC 2023-06-09 16:25:23 -07:00
failslab.c
filemap.c mm: filemap: batch mm counter updating in filemap_map_pages() 2024-05-05 17:53:36 -07:00
folio-compat.c mm: remove __set_page_dirty_nobuffers() 2024-04-25 20:56:25 -07:00
gup_test.c Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-06-23 16:58:19 -07:00
gup_test.h
gup.c gup: use folios for gup_devmap 2024-05-05 17:53:49 -07:00
highmem.c x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs 2023-12-29 12:22:28 -08:00
hmm.c mm/treewide: replace pXd_huge() with pXd_leaf() 2024-04-25 20:55:46 -07:00
huge_memory.c mm/huge_memory: improve split_huge_page_to_list_to_order() return value documentation 2024-05-05 17:53:42 -07:00
hugetlb_cgroup.c mm/hugetlb: assert hugetlb_lock in __hugetlb_cgroup_commit_charge 2024-05-05 17:53:41 -07:00
hugetlb_vmemmap.c memory: remove the now superfluous sentinel element from ctl_table array 2024-04-25 20:56:32 -07:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: fix reference to nonexistent file 2023-10-25 16:47:14 -07:00
hugetlb.c mm: convert hugetlb_page_mapping_lock_write to folio 2024-05-05 17:53:46 -07:00
hwpoison-inject.c mm/memory-failure: convert shake_page() to shake_folio() 2024-05-05 17:53:45 -07:00
init-mm.c mm: Deprecate pasid field 2023-12-12 10:11:32 +01:00
internal.h mm/memory-failure: convert shake_page() to shake_folio() 2024-05-05 17:53:45 -07:00
interval_tree.c
io-mapping.c
ioremap.c mm: ioremap: remove unneeded ioremap_allowed and iounmap_allowed 2023-08-18 10:12:36 -07:00
Kconfig mm/treewide: rename CONFIG_HAVE_FAST_GUP to CONFIG_HAVE_GUP_FAST 2024-04-25 20:56:41 -07:00
Kconfig.debug mm/slub: unify all sl[au]b parameters with "slab_$param" 2024-01-22 10:31:08 +01:00
khugepaged.c mm/khugepaged: replace page_mapcount() check by folio_likely_mapped_shared() 2024-05-05 17:53:50 -07:00
kmemleak.c mm/kmemleak: compact kmemleak_object further 2024-04-25 20:56:05 -07:00
ksm.c mm/memory-failure: pass the folio to collect_procs_ksm() 2024-05-05 17:53:47 -07:00
list_lru.c mm/zswap: stop lru list shrinking when encounter warm region 2024-02-22 10:24:54 -08:00
maccess.c
madvise.c mm/madvise: optimize lazyfreeing with mTHP in madvise_free 2024-05-05 17:53:43 -07:00
Makefile mm/kmemleak: disable KASAN instrumentation in kmemleak 2024-04-25 20:56:05 -07:00
mapping_dirty_helpers.c mm: fix clean_record_shared_mapping_range kernel-doc 2023-08-24 16:20:30 -07:00
memblock.c cxl fixes for 6.8-rc6 2024-02-24 15:53:40 -08:00
memcontrol.c memcg: fix data-race KCSAN bug in rstats 2024-05-05 17:53:50 -07:00
memfd.c mm/memfd: refactor memfd_tag_pins() and memfd_wait_for_pins() 2024-03-04 17:01:21 -08:00
memory_hotplug.c mm/hugetlb: rename dissolve_free_huge_pages() to dissolve_free_hugetlb_folios() 2024-05-05 17:53:35 -07:00
memory-failure.c memory-failure: remove calls to page_mapping() 2024-05-05 17:53:48 -07:00
memory-tiers.c memory tier: create CPUless memory tiers after obtaining HMAT info 2024-05-05 17:53:26 -07:00
memory.c mm: memory: check userfaultfd_wp() in vmf_orig_pte_uffd_wp() 2024-05-05 17:53:43 -07:00
mempolicy.c mm: add pmd_folio() 2024-04-25 20:56:19 -07:00
mempool.c mempool: hook up to memory allocation profiling 2024-04-25 20:55:56 -07:00
memremap.c mm: convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs() 2024-05-05 17:53:49 -07:00
memtest.c memtest: use {READ,WRITE}_ONCE in memory scanning 2024-03-13 12:12:21 -07:00
migrate_device.c migrate: expand the use of folio in __migrate_device_pages() 2024-05-05 17:53:48 -07:00
migrate.c mm: convert hugetlb_page_mapping_lock_write to folio 2024-05-05 17:53:46 -07:00
mincore.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
mlock.c mm: add pmd_folio() 2024-04-25 20:56:19 -07:00
mm_init.c mm: init_mlocked_on_free_v3 2024-04-25 20:56:29 -07:00
mm_slot.h
mmap_lock.c
mmap.c mm/mmap: make accountable_mapping return bool 2024-05-05 17:53:26 -07:00
mmu_gather.c mm/mmu_gather: improve cond_resched() handling with large folios and expensive page freeing 2024-02-22 15:27:17 -08:00
mmu_notifier.c mmu_notifiers: rename invalidate_range notifier 2023-08-18 10:12:41 -07:00
mmzone.c zswap: shrink zswap pool based on memory pressure 2023-12-12 10:57:02 -08:00
mprotect.c mm: support multi-size THP numa balancing 2024-04-25 20:56:30 -07:00
mremap.c mm: remove "prot" parameter from move_pte() 2024-04-25 20:56:24 -07:00
msync.c
nommu.c mm: remove follow_pfn 2024-04-25 20:56:12 -07:00
oom_kill.c memory: remove the now superfluous sentinel element from ctl_table array 2024-04-25 20:56:32 -07:00
page_alloc.c mm: page_alloc: allowing mTHP compaction to capture the freed page directly 2024-05-05 17:53:37 -07:00
page_counter.c
page_ext.c mm: make page_ext_get() take a const argument 2024-04-25 20:56:14 -07:00
page_idle.c
page_io.c mm: add per-order mTHP anon_swpout and anon_swpout_fallback counters 2024-05-05 17:53:35 -07:00
page_isolation.c mm: page_isolation: prepare for hygienic freelists 2024-04-25 20:56:04 -07:00
page_owner.c mm: introduce slabobj_ext to support slab object extensions 2024-04-25 20:55:51 -07:00
page_poison.c mm/page_poison: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:50 -08:00
page_reporting.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_reporting.h
page_table_check.c mm/page_table_check: support userfault wr-protect entries 2024-05-05 17:53:41 -07:00
page_vma_mapped.c mm: make page_mapped_in_vma conditional on CONFIG_MEMORY_FAILURE 2024-05-05 17:53:45 -07:00
page-writeback.c doc: improve the description of __folio_mark_dirty 2024-05-05 17:53:39 -07:00
pagewalk.c mm: pagewalk: assert write mmap lock only for walking the user page tables 2023-12-10 16:51:53 -08:00
percpu-internal.h mm: percpu: add codetag reference into pcpuobj_ext 2024-04-25 20:55:56 -07:00
percpu-km.c
percpu-stats.c
percpu-vm.c percpu: clean up all mappings when pcpu_map_pages() fails 2024-04-25 20:55:49 -07:00
percpu.c mm: percpu: enable per-cpu allocation tagging 2024-04-25 20:55:56 -07:00
pgalloc-track.h
pgtable-generic.c mm/pgtable: notes on pte_offset_map[_lock]() 2023-08-18 10:12:25 -07:00
process_vm_access.c mm: fix process_vm_rw page counts 2023-12-10 16:51:39 -08:00
ptdump.c mm: ptdump: add check_wx_pages debugfs attribute 2024-02-22 10:24:47 -08:00
readahead.c mm/readahead: break read-ahead loop if filemap_add_folio return -ENOMEM 2024-04-25 20:56:07 -07:00
rmap.c mm: track mapcount of large folios in single value 2024-05-05 17:53:28 -07:00
rodata_test.c
secretmem.c mm/secretmem: use a folio in secretmem_fault() 2023-08-21 13:38:02 -07:00
shmem_quota.c tmpfs: fix race on handling dquot rbtree 2024-03-26 11:07:23 -07:00
shmem.c mm: switch mm->get_unmapped_area() to a flag 2024-04-25 20:56:25 -07:00
show_mem.c lib: add memory allocations report in show_mem() 2024-04-25 20:55:57 -07:00
shrinker_debug.c mm: shrinker: convert shrinker_rwsem to mutex 2023-10-04 10:32:26 -07:00
shrinker.c mm: shrinker: use kvzalloc_node() from expand_one_shrinker_info() 2024-01-05 09:58:32 -08:00
shuffle.c
shuffle.h mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
slab_common.c mm/slab: enable slab allocation tagging for kmalloc and friends 2024-04-25 20:55:55 -07:00
slab.h memcg: simple cleanup of stats update functions 2024-05-05 17:53:44 -07:00
slub.c mm, slab: move slab_memcg hooks to mm/memcontrol.c 2024-04-25 20:56:16 -07:00
sparse-vmemmap.c mm/vmemmap: allow architectures to override how vmemmap optimization works 2023-08-18 10:12:53 -07:00
sparse.c mm/sparse: guard the size of mem_section is power of 2 2024-05-05 17:53:40 -07:00
swap_cgroup.c
swap_slots.c mm: swap: update get_swap_pages() to take folio order 2024-04-25 20:56:37 -07:00
swap_state.c mm: remove struct page from get_shadow_from_swap_cache 2024-04-25 20:56:40 -07:00
swap.c mm: add kernel-doc for folio_mark_accessed() 2024-05-05 17:53:50 -07:00
swap.h mm/swap: fix race when skipping swapcache 2024-02-20 14:20:48 -08:00
swapfile.c mm: swapfile: check usable swap device in __folio_throttle_swaprate() 2024-05-05 17:53:42 -07:00
truncate.c mm: convert pagecache_isize_extended to use a folio 2024-04-25 20:56:43 -07:00
usercopy.c
userfaultfd.c userfault; expand folio use in mfill_atomic_install_pte() 2024-05-05 17:53:48 -07:00
util.c mm: switch mm->get_unmapped_area() to a flag 2024-04-25 20:56:25 -07:00
vmalloc.c mm: vmalloc: dump page owner info if page is already mapped 2024-05-05 17:53:51 -07:00
vmpressure.c eventfd: simplify eventfd_signal() 2023-11-28 14:08:38 +01:00
vmscan.c mm: add per-order mTHP anon_swpout and anon_swpout_fallback counters 2024-05-05 17:53:35 -07:00
vmstat.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
workingset.c mm: move mapping_set_update out of <linux/swap.h> 2024-02-21 11:36:50 +05:30
z3fold.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zbud.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zpool.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zsmalloc.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zswap.c mm: zswap: remove same_filled module params 2024-05-05 17:53:38 -07:00