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Jens Axboe 63135aa386 mm: provide filemap_range_needs_writeback() helper 
Patch series "Improve IOCB_NOWAIT O_DIRECT reads", v3.

An internal workload complained because it was using too much CPU, and
when I took a look, we had a lot of io_uring workers going to town.

For an async buffered read like workload, I am normally expecting _zero_
offloads to a worker thread, but this one had tons of them.  I'd drop
caches and things would look good again, but then a minute later we'd
regress back to using workers.  Turns out that every minute something
was reading parts of the device, which would add page cache for that
inode.  I put patches like these in for our kernel, and the problem was
solved.

Don't -EAGAIN IOCB_NOWAIT dio reads just because we have page cache
entries for the given range.  This causes unnecessary work from the
callers side, when the IO could have been issued totally fine without
blocking on writeback when there is none.

This patch (of 3):

For O_DIRECT reads/writes, we check if we need to issue a call to
filemap_write_and_wait_range() to issue and/or wait for writeback for any
page in the given range.  The existing mechanism just checks for a page in
the range, which is suboptimal for IOCB_NOWAIT as we'll fallback to the
slow path (and needing retry) if there's just a clean page cache page in
the range.

Provide filemap_range_needs_writeback() which tries a little harder to
check if we actually need to issue and/or wait for writeback in the range.

Link: https://lkml.kernel.org/r/20210224164455.1096727-1-axboe@kernel.dk
Link: https://lkml.kernel.org/r/20210224164455.1096727-2-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2021-04-30 11:20:36 -07:00
..
kasan arm64 updates for 5.13: 2021-04-26 10:25:03 -07:00
kfence kfence: make compatible with kmemleak 2021-03-25 09:22:55 -07:00
Kconfig block: remove BLK_BOUNCE_ISA support 2021-04-06 09:28:17 -06:00
Kconfig.debug mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO 2020-12-15 12:13:46 -08:00
Makefile mm: add Kernel Electric-Fence infrastructure 2021-02-26 09:41:02 -08:00
backing-dev.c mm/backing-dev.c: use might_alloc() 2021-02-26 09:41:01 -08:00
balloon_compaction.c
…
cleancache.c
…
cma.c mm: cma: print region name on failure 2021-02-26 09:41:00 -08:00
cma.h mm: cma: use CMA_MAX_NAME to define the length of cma name array 2020-09-01 09:19:43 +02:00
cma_debug.c debugfs: make sure we can remove u32_array files cleanly 2020-07-10 13:54:00 -07:00
compaction.c mm, compaction: make fast_isolate_freepages() stay within zone 2021-02-24 13:38:34 -08:00
debug.c mm/debug: improve memcg debugging 2021-02-24 13:38:27 -08:00
debug_page_ref.c
…
debug_vm_pgtable.c mm/debug_vm_pgtable/basic: iterate over entire protection_map[] 2021-02-24 13:38:27 -08:00
dmapool.c mm/dmapool: use might_alloc() 2021-02-26 09:41:01 -08:00
early_ioremap.c mm/early_ioremap.c: use __func__ instead of function name 2021-02-26 09:41:02 -08:00
fadvise.c mm, fadvise: improve the expensive remote LRU cache draining after FADV_DONTNEED 2020-10-13 18:38:29 -07:00
failslab.c
…
filemap.c mm: provide filemap_range_needs_writeback() helper 2021-04-30 11:20:36 -07:00
frontswap.c mm/frontswap: mark various intentional data races 2020-08-14 19:56:56 -07:00
gup.c mm/gup: check page posion status for coredump. 2021-04-09 14:54:23 -07:00
gup_test.c mm/gup_test.c: mark gup_test_init as __init function 2020-12-15 12:13:38 -08:00
gup_test.h selftests/vm: gup_test: introduce the dump_pages() sub-test 2020-12-15 12:13:38 -08:00
highmem.c mm/highmem: fix CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP 2021-03-25 09:22:55 -07:00
hmm.c mm: do page fault accounting in handle_mm_fault 2020-08-12 10:58:02 -07:00
huge_memory.c mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument 2021-03-13 11:27:31 -08:00
hugetlb.c hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings 2021-03-25 09:22:55 -07:00
hugetlb_cgroup.c hugetlb_cgroup: fix imbalanced css_get and css_put pair for shared mappings 2021-03-25 09:22:55 -07:00
hwpoison-inject.c mm,hwpoison-inject: don't pin for hwpoison_filter 2020-10-16 11:11:16 -07:00
init-mm.c mm/gup: prevent gup_fast from racing with COW during fork 2020-12-15 12:13:39 -08:00
internal.h Network filesystem helper library 2021-04-27 13:08:12 -07:00
interval_tree.c
…
ioremap.c mm: move p?d_alloc_track to separate header file 2020-08-07 11:33:26 -07:00
khugepaged.c mm,thp,shmem: make khugepaged obey tmpfs mount flags 2021-02-26 09:40:59 -08:00
kmemleak.c mm/kmemleak.c: fix a typo 2021-04-30 11:20:36 -07:00
ksm.c mm: cleanup kstrto*() usage 2020-12-15 12:13:47 -08:00
list_lru.c mm/list_lru.c: remove kvfree_rcu_local() 2021-02-24 13:38:30 -08:00
maccess.c uaccess: add force_uaccess_{begin,end} helpers 2020-08-12 10:57:59 -07:00
madvise.c mm/madvise: replace ptrace attach requirement for process_madvise 2021-03-13 11:27:30 -08:00
mapping_dirty_helpers.c mm/mapping_dirty_helpers: guard hugepage pud's usage 2021-04-16 16:10:37 -07:00
memblock.c memblock: remove return value of memblock_free_all() 2021-02-22 13:01:23 -08:00
memcontrol.c mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument 2021-03-13 11:27:31 -08:00
memfd.c
…
memory-failure.c mm: fix memory_failure() handling of dax-namespace metadata 2021-02-26 09:41:00 -08:00
memory.c mm: fix race by making init_zero_pfn() early_initcall 2021-03-30 09:46:12 -07:00
memory_hotplug.c arm64: mte: Map hotplugged memory as Normal Tagged 2021-03-10 10:56:46 +00:00
mempolicy.c mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk() 2021-02-24 13:38:34 -08:00
mempool.c kasan: move _RET_IP_ to inline wrappers 2021-02-24 13:38:31 -08:00
memremap.c mm/memory_hotplug: prevalidate the address range being added with platform 2021-02-26 09:41:00 -08:00
memtest.c
…
migrate.c mm: memcg: add swapcache stat for memcg v2 2021-02-24 13:38:29 -08:00
mincore.c inode: make init and permission helpers idmapped mount aware 2021-01-24 14:27:16 +01:00
mlock.c mm/mlock: stop counting mlocked pages when none vma is found 2021-02-26 09:41:01 -08:00
mm_init.c mm: fix fall-through warnings for Clang 2020-12-15 12:13:47 -08:00
mmap.c arm64: Support execute-only permissions with Enhanced PAN 2021-03-26 09:37:23 +00:00
mmap_lock.c mm: mmap_lock: add tracepoints around lock acquisition 2020-12-15 12:13:41 -08:00
mmu_gather.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
mmu_notifier.c mm/mmu_notifiers: ensure range_end() is paired with range_start() 2021-03-25 09:22:55 -07:00
mmzone.c mm/lru: replace pgdat lru_lock with lruvec lock 2020-12-15 14:48:04 -08:00
mprotect.c mm/mprotect.c: optimize error detection in do_mprotect_pkey() 2021-02-24 13:38:30 -08:00
mremap.c mm: mremap: unlink anon_vmas when mremap with MREMAP_DONTUNMAP success 2021-02-24 13:38:30 -08:00
msync.c
…
nommu.c mm/nommu: Fix return type of filemap_map_pages() 2021-01-28 14:10:31 +00:00
oom_kill.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
page-writeback.c mm/writeback: Add wait_on_page_writeback_killable 2021-03-23 20:54:29 +00:00
page_alloc.c init_on_alloc: Optimize static branches 2021-04-08 14:05:19 +02:00
page_counter.c mm/page_counter: use page_counter_read in page_counter_set_max 2020-12-15 12:13:40 -08:00
page_ext.c mm: fix some spelling mistakes in comments 2020-12-15 22:46:19 -08:00
page_idle.c mm: page_idle_get_page() does not need lru_lock 2020-12-15 14:48:03 -08:00
page_io.c swap: fix swapfile read/write offset 2021-03-02 17:25:46 -07:00
page_isolation.c mm/page_isolation: do not isolate the max order page 2020-12-15 12:13:45 -08:00
page_owner.c mm: page_owner: detect page_owner recursion via task_struct 2021-04-30 11:20:36 -07:00
page_poison.c mm: page_poison: print page info when corruption is caught 2021-04-30 11:20:36 -07:00
page_reporting.c mm/page_reporting: use list_entry_is_head() in page_reporting_cycle() 2021-02-24 13:38:30 -08:00
page_reporting.h
…
page_vma_mapped.c mm/page_vma_mapped.c: add colon to fix kernel-doc markups error for check_pte 2020-12-15 12:13:41 -08:00
pagewalk.c
…
percpu-internal.h percpu: make pcpu_nr_empty_pop_pages per chunk type 2021-04-09 13:58:38 +00:00
percpu-km.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu-stats.c percpu: make pcpu_nr_empty_pop_pages per chunk type 2021-04-09 13:58:38 +00:00
percpu-vm.c mm: memcg/percpu: account percpu memory to memory cgroups 2020-08-12 10:57:55 -07:00
percpu.c percpu: make pcpu_nr_empty_pop_pages per chunk type 2021-04-09 13:58:38 +00:00
pgalloc-track.h mm: move p?d_alloc_track to separate header file 2020-08-07 11:33:26 -07:00
pgtable-generic.c mm/pgtable-generic.c: optimize the VM_BUG_ON condition in pmdp_huge_clear_flush() 2021-02-24 13:38:30 -08:00
process_vm_access.c mm/process_vm_access.c: include compat.h 2021-01-12 18:12:54 -08:00
ptdump.c mm: ptdump: fix build failure 2021-04-16 16:10:37 -07:00
readahead.c mm: Implement readahead_control pageset expansion 2021-04-23 10:14:29 +01:00
rmap.c mm/rmap: correct obsolete comment of page_get_anon_vma() 2021-02-26 09:41:01 -08:00
rodata_test.c mm/rodata_test.c: fix missing function declaration 2020-08-21 09:52:53 -07:00
shmem.c shmem: allow reporting fanotify events with file handles on tmpfs 2021-04-19 16:03:48 +02:00
shuffle.c mm: eliminate "expecting prototype" kernel-doc warnings 2021-04-16 16:10:36 -07:00
shuffle.h mm/shuffle: remove dynamic reconfiguration 2020-08-07 11:33:29 -07:00
slab.c Merge branch 'for-mingo-rcu' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu 2021-04-11 14:31:43 +02:00
slab.h RCU changes for this cycle were: 2021-04-28 12:00:13 -07:00
slab_common.c mm/slab_common: provide "slab_merge" option for !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT) builds 2021-04-30 11:20:36 -07:00
slob.c mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels 2021-03-08 14:18:46 -08:00
slub.c mm/slub.c: trivial typo fixes 2021-04-30 11:20:36 -07:00
sparse-vmemmap.c mm/sparse: only sub-section aligned range would be populated 2020-08-07 11:33:27 -07:00
sparse.c mm/memory_hotplug: guard more declarations by CONFIG_MEMORY_HOTPLUG 2020-10-16 11:11:18 -07:00
swap.c mm: remove pagevec_lookup_entries 2021-02-26 09:40:59 -08:00
swap_cgroup.c
…
swap_slots.c mm/swap_slots.c: remove redundant NULL check 2021-02-24 13:38:28 -08:00
swap_state.c mm: add FGP_ENTRY 2021-02-26 09:40:59 -08:00
swapfile.c swap: fix swapfile read/write offset 2021-03-02 17:25:46 -07:00
truncate.c mm: remove pagevec_lookup_entries 2021-02-26 09:40:59 -08:00
usercopy.c mm/usercopy.c: delete duplicated word 2020-08-12 10:57:58 -07:00
userfaultfd.c mm/vmscan: protect the workingset on anonymous LRU 2020-08-12 10:57:55 -07:00
util.c rcutorture: Add crude tests for mem_dump_obj() 2021-03-08 14:18:46 -08:00
vmacache.c
…
vmalloc.c mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels 2021-03-08 14:18:46 -08:00
vmpressure.c
…
vmscan.c mm/vmscan: restore zone_reclaim_mode ABI 2021-02-24 13:38:34 -08:00
vmstat.c mm/vmstat.c: erase latency in vmstat_shepherd 2021-02-26 09:41:00 -08:00
workingset.c mm: workingset: clarify eviction order and distance calculation 2021-02-24 13:38:34 -08:00
z3fold.c z3fold: prevent reclaim/free race for headless pages 2021-03-25 09:22:55 -07:00
zbud.c mm: set the sleep_mapped to true for zbud and z3fold 2021-02-26 09:41:01 -08:00
zpool.c mm/zswap: add the flag can_sleep_mapped 2021-02-26 09:41:01 -08:00
zsmalloc.c mm/zsmalloc.c: use page_private() to access page->private 2021-02-26 09:41:01 -08:00
zswap.c mm/zswap: add the flag can_sleep_mapped 2021-02-26 09:41:01 -08:00