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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-07 21:39:33 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-07 21:39:33 +0300 |
commit | 81e11336d97e7a4c25a65c302ef2bf9cd9808ed4 (patch) | |
tree | 44e069e0bb26068137a1bda7ca5125c5b068b4ab /lib/percpu_counter.c | |
parent | 5631c5e0eb9035d92ceb20fcd9cdb7779a3f5cc7 (diff) | |
parent | 912c05720f00d039103d356a59c37dc7c3995e01 (diff) | |
download | linux-81e11336d97e7a4c25a65c302ef2bf9cd9808ed4.tar.xz |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton:
- a few MM hotfixes
- kthread, tools, scripts, ntfs and ocfs2
- some of MM
Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
mm: vmscan: consistent update to pgrefill
mm/vmscan.c: fix typo
khugepaged: khugepaged_test_exit() check mmget_still_valid()
khugepaged: retract_page_tables() remember to test exit
khugepaged: collapse_pte_mapped_thp() protect the pmd lock
khugepaged: collapse_pte_mapped_thp() flush the right range
mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
mm: thp: replace HTTP links with HTTPS ones
mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
mm/page_alloc.c: skip setting nodemask when we are in interrupt
mm/page_alloc: fallbacks at most has 3 elements
mm/page_alloc: silence a KASAN false positive
mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
mm/page_alloc.c: simplify pageblock bitmap access
mm/page_alloc.c: extract the common part in pfn_to_bitidx()
mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
mm/shuffle: remove dynamic reconfiguration
mm/memory_hotplug: document why shuffle_zone() is relevant
mm/page_alloc: remove nr_free_pagecache_pages()
mm: remove vm_total_pages
...
Diffstat (limited to 'lib/percpu_counter.c')
-rw-r--r-- | lib/percpu_counter.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index a66595ba5543..a2345de90e93 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -99,6 +99,25 @@ void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount, s32 batch) EXPORT_SYMBOL(percpu_counter_add_batch); /* + * For percpu_counter with a big batch, the devication of its count could + * be big, and there is requirement to reduce the deviation, like when the + * counter's batch could be runtime decreased to get a better accuracy, + * which can be achieved by running this sync function on each CPU. + */ +void percpu_counter_sync(struct percpu_counter *fbc) +{ + unsigned long flags; + s64 count; + + raw_spin_lock_irqsave(&fbc->lock, flags); + count = __this_cpu_read(*fbc->counters); + fbc->count += count; + __this_cpu_sub(*fbc->counters, count); + raw_spin_unlock_irqrestore(&fbc->lock, flags); +} +EXPORT_SYMBOL(percpu_counter_sync); + +/* * Add up all the per-cpu counts, return the result. This is a more accurate * but much slower version of percpu_counter_read_positive() */ |