Howard Cochran 81b76485af writeback: Fix performance regression in wb_over_bg_thresh() ... Commit 947e9762a8 ("writeback: update wb_over_bg_thresh() to use wb_domain aware operations") unintentionally changed this function's meaning from "are there more dirty pages than the background writeback threshold" to "are there more dirty pages than the writeback threshold". The background writeback threshold is typically half of the writeback threshold, so this had the effect of raising the number of dirty pages required to cause a writeback worker to perform background writeout. This can cause a very severe performance regression when a BDI uses BDI_CAP_STRICTLIMIT because balance_dirty_pages() and the writeback worker can now disagree on whether writeback should be initiated. For example, in a system having 1GB of RAM, a single spinning disk, and a "pass-through" FUSE filesystem mounted over the disk, application code mmapped a 128MB file on the disk and was randomly dirtying pages in that mapping. Because FUSE uses strictlimit and has a default max_ratio of only 1%, in balance_dirty_pages, thresh is ~200, bg_thresh is ~100, and the dirty_freerun_ceiling is the average of those, ~150. So, it pauses the dirtying processes when we have 151 dirty pages and wakes up a background writeback worker. But the worker tests the wrong threshold (200 instead of 100), so it does not initiate writeback and just returns. Thus, balance_dirty_pages keeps looping, sleeping and then waking up the worker who will do nothing. It remains stuck in this state until the few dirty pages that we have finally expire and we write them back for that reason. Then the whole process repeats, resulting in near-zero throughput through the FUSE BDI. The fix is to call the parameterized variant of wb_calc_thresh, so that the worker will do writeback if the bg_thresh is exceeded which was the bahavior before the referenced commit. Fixes: 947e9762a8 ("writeback: update wb_over_bg_thresh() to use wb_domain aware operations") Signed-off-by: Howard Cochran <hcochran@kernelspring.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>		2016-04-12 10:01:00 -06:00
..
kasan	mm, kasan: fix compilation for CONFIG_SLAB	2016-04-01 17:03:37 -05:00
backing-dev.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
balloon_compaction.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2016-03-17 21:38:27 -07:00
bootmem.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
cleancache.c	cleancache: constify cleancache_ops structure	2016-01-27 09:09:57 -05:00
cma.c	mm/cma.c: suppress warning	2015-11-05 19:34:48 -08:00
cma.h	mm: cma: mark cma_bitmap_maxno() inline in header	2015-08-14 15:56:32 -07:00
cma_debug.c	mm/cma_debug: correct size input to bitmap function	2015-07-17 16:39:54 -07:00
compaction.c	mm, kswapd: replace kswapd compaction with waking up kcompactd	2016-03-17 15:09:34 -07:00
debug.c	mm: introduce page reference manipulation functions	2016-03-17 15:09:34 -07:00
debug_page_ref.c	mm/page_ref: add tracepoint to track down page reference manipulation	2016-03-17 15:09:34 -07:00
dmapool.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
early_ioremap.c	mm/early_ioremap: use offset_in_page macro	2015-11-05 19:34:48 -08:00
fadvise.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
failslab.c	mm: fault-inject take over bootstrap kmem_cache check	2016-03-15 16:55:16 -07:00
filemap.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
frame_vector.c	mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm	2016-02-16 10:11:12 +01:00
frontswap.c	frontswap: allow multiple backends	2015-06-24 17:49:45 -07:00
gup.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
highmem.c
huge_memory.c	thp: fix typo in khugepaged_scan_pmd()	2016-03-25 16:37:42 -07:00
hugetlb.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
hugetlb_cgroup.c	mm: make compound_head() robust	2015-11-06 17:50:42 -08:00
hwpoison-inject.c	hwpoison: use page_cgroup_ino for filtering by memcg	2015-09-10 13:29:01 -07:00
init-mm.c
internal.h	mm, oom: introduce oom reaper	2016-03-25 16:37:42 -07:00
interval_tree.c	mm: replace vma->sharead.linear with vma->shared	2015-02-10 14:30:31 -08:00
Kconfig	Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-20 19:08:56 -07:00
Kconfig.debug	mm/page_ref: add tracepoint to track down page reference manipulation	2016-03-17 15:09:34 -07:00
kmemcheck.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
kmemleak-test.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
kmemleak.c	mm: coalesce split strings	2016-03-17 15:09:34 -07:00
ksm.c	mm/core: Do not enforce PKEY permissions on remote mm access	2016-02-18 19:46:28 +01:00
list_lru.c	mm: memcontrol: move kmem accounting code to CONFIG_MEMCG	2016-01-20 17:09:18 -08:00
maccess.c	mm/maccess.c: actually return -EFAULT from strncpy_from_unsafe	2015-11-05 19:34:48 -08:00
madvise.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
Makefile	mm, kasan: SLAB support	2016-03-25 16:37:42 -07:00
memblock.c	mm: coalesce split strings	2016-03-17 15:09:34 -07:00
memcontrol.c	mm: memcontrol: zap oom_info_lock	2016-03-17 15:09:34 -07:00
memory-failure.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
memory.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
memory_hotplug.c	mm: coalesce split strings	2016-03-17 15:09:34 -07:00
mempolicy.c	Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-20 19:08:56 -07:00
mempool.c	mm, kasan: add GFP flags to KASAN API	2016-03-25 16:37:42 -07:00
memtest.c	memtest: remove unused header files	2015-09-08 15:35:28 -07:00
migrate.c	mm: make remove_migration_ptes() beyond mm/migration.c	2016-03-17 15:09:34 -07:00
mincore.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
mlock.c	mm: fix mlock accouting	2016-01-21 17:20:51 -08:00
mm_init.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
mmap.c	Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-20 19:08:56 -07:00
mmu_context.c
mmu_notifier.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
mmzone.c	mm/mmzone.c: memmap_valid_within() can be boolean	2016-01-14 16:00:49 -08:00
mprotect.c	mm/mprotect.c: don't imply PROT_EXEC on non-exec fs	2016-03-22 15:36:02 -07:00
mremap.c	mm: cleanup *pte_alloc* interfaces	2016-03-17 15:09:34 -07:00
msync.c	mm/msync: use offset_in_page macro	2015-11-05 19:34:48 -08:00
nobootmem.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
nommu.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
oom_kill.c	oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head	2016-04-01 17:03:37 -05:00
page-writeback.c	writeback: Fix performance regression in wb_over_bg_thresh()	2016-04-12 10:01:00 -06:00
page_alloc.c	mm/page_alloc: prevent merging between isolated and other pageblocks	2016-03-25 16:37:42 -07:00
page_counter.c	mm: page_counter: let page_counter_try_charge() return bool	2015-11-05 19:34:48 -08:00
page_ext.c	mm/page_poisoning.c: allow for zero poisoning	2016-03-15 16:55:16 -07:00
page_idle.c	mm: add page_check_address_transhuge() helper	2016-01-15 17:56:32 -08:00
page_io.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
page_isolation.c	mm/page_isolation.c: fix the function comments	2016-04-01 17:03:37 -05:00
page_owner.c	mm: coalesce split strings	2016-03-17 15:09:34 -07:00
page_poison.c	mm/page_poisoning.c: allow for zero poisoning	2016-03-15 16:55:16 -07:00
pagewalk.c	thp: rename split_huge_page_pmd() to split_huge_pmd()	2016-01-15 17:56:32 -08:00
percpu-km.c	mm: percpu: use pr_fmt to prefix output	2016-03-17 15:09:34 -07:00
percpu-vm.c
percpu.c	mm: percpu: use pr_fmt to prefix output	2016-03-17 15:09:34 -07:00
pgtable-generic.c	mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range	2016-03-17 15:09:34 -07:00
process_vm_access.c	mm/gup: Introduce get_user_pages_remote()	2016-02-16 10:04:09 +01:00
quicklist.c	fix Christoph's email addresses	2016-03-17 15:09:34 -07:00
readahead.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
rmap.c	Merge branch 'PAGE_CACHE_SIZE-removal'	2016-04-04 10:50:24 -07:00
shmem.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
slab.c	mm, kasan: add GFP flags to KASAN API	2016-03-25 16:37:42 -07:00
slab.h	mm, kasan: add GFP flags to KASAN API	2016-03-25 16:37:42 -07:00
slab_common.c	mm, kasan: add GFP flags to KASAN API	2016-03-25 16:37:42 -07:00
slob.c	mm: slab: free kmem_cache_node after destroy sysfs file	2016-02-18 16:23:24 -08:00
slub.c	mm, kasan: add GFP flags to KASAN API	2016-03-25 16:37:42 -07:00
sparse-vmemmap.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
sparse.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
swap.c	mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage	2016-04-04 10:41:08 -07:00
swap_cgroup.c	mm: convert printk(KERN_<LEVEL> to pr_<level>	2016-03-17 15:09:34 -07:00
swap_state.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
swapfile.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
truncate.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
userfaultfd.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00
util.c	Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-03-20 19:08:56 -07:00
vmacache.c	mm/vmacache: inline vmacache_valid_mm()	2015-11-05 19:34:48 -08:00
vmalloc.c	mm/vmalloc: use PAGE_ALIGNED() to check PAGE_SIZE alignment	2016-03-17 15:09:34 -07:00
vmpressure.c	mm/vmpressure.c: fix subtree pressure detection	2016-02-03 08:28:43 -08:00
vmscan.c	mm: introduce page reference manipulation functions	2016-03-17 15:09:34 -07:00
vmstat.c	thp, vmstats: count deferred split events	2016-03-17 15:09:34 -07:00
workingset.c	mm: workingset: make shadow node shrinker memcg aware	2016-03-17 15:09:34 -07:00
zbud.c	mm/zbud.c: use list_last_entry() instead of list_tail_entry()	2016-01-15 11:40:52 -08:00
zpool.c	mm: zsmalloc: constify struct zs_pool name	2015-11-06 17:50:42 -08:00
zsmalloc.c	mm/zsmalloc: add `freeable' column to pool stat	2016-03-17 15:09:34 -07:00
zswap.c	mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros	2016-04-04 10:41:08 -07:00