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| author | Yury Norov <yury.norov@gmail.com> | 2021-08-14 14:17:10 -0700 |
|---|---|---|
| committer | Yury Norov <yury.norov@gmail.com> | 2022-01-15 08:47:31 -0800 |
| commit | 801a57365fc836d7ec866e2069d0b21d79925c1e (patch) | |
| tree | 76af2ac9496f91c85eb00a66be42235c82a1bbc6 /mm/percpu.c | |
| parent | 749443de8dde3b8b420ee8b4daac4d929a6adeb9 (diff) | |
| download | linux-stable-801a57365fc836d7ec866e2069d0b21d79925c1e.tar.gz linux-stable-801a57365fc836d7ec866e2069d0b21d79925c1e.tar.bz2 linux-stable-801a57365fc836d7ec866e2069d0b21d79925c1e.zip | |
mm/percpu: micro-optimize pcpu_is_populated()
bitmap_next_clear_region() calls find_next_zero_bit() and find_next_bit()
sequentially to find a range of clear bits. In case of pcpu_is_populated()
there's a chance to return earlier if bitmap has all bits set.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Dennis Zhou <dennis@kernel.org>
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index f5b2c2ea5a54..0c6f85c5514f 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1070,17 +1070,18 @@ static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off, static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, int *next_off) { - unsigned int page_start, page_end, rs, re; + unsigned int start, end; - page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); - page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); + start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); + end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); - rs = page_start; - bitmap_next_clear_region(chunk->populated, &rs, &re, page_end); - if (rs >= page_end) + start = find_next_zero_bit(chunk->populated, end, start); + if (start >= end) return true; - *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; + end = find_next_bit(chunk->populated, end, start + 1); + + *next_off = end * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; return false; } |