From 86b442fbce74d6cd0805410ef228776cbd0338d7 Mon Sep 17 00:00:00 2001 From: "Dennis Zhou (Facebook)" Date: Mon, 24 Jul 2017 19:02:13 -0400 Subject: percpu: add first_bit to keep track of the first free in the bitmap This patch adds first_bit to keep track of the first free bit in the bitmap. This hint helps prevent scanning of fully allocated blocks. Signed-off-by: Dennis Zhou Reviewed-by: Josef Bacik Signed-off-by: Tejun Heo --- mm/percpu.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'mm/percpu.c') diff --git a/mm/percpu.c b/mm/percpu.c index 708c6de237b9..83abb190ca5a 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -427,7 +427,7 @@ static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) chunk->contig_bits = 0; bits = nr_empty_pop_pages = 0; - pcpu_for_each_unpop_region(chunk->alloc_map, rs, re, 0, + pcpu_for_each_unpop_region(chunk->alloc_map, rs, re, chunk->first_bit, pcpu_chunk_map_bits(chunk)) { bits = re - rs; @@ -646,7 +646,8 @@ static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, int bit_off, bits; int re; /* region end */ - pcpu_for_each_unpop_region(chunk->alloc_map, bit_off, re, 0, + pcpu_for_each_unpop_region(chunk->alloc_map, bit_off, re, + chunk->first_bit, pcpu_chunk_map_bits(chunk)) { bits = re - bit_off; @@ -715,6 +716,13 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE; + /* update first free bit */ + if (bit_off == chunk->first_bit) + chunk->first_bit = find_next_zero_bit( + chunk->alloc_map, + pcpu_chunk_map_bits(chunk), + bit_off + alloc_bits); + pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits); pcpu_chunk_relocate(chunk, oslot); @@ -750,6 +758,9 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int off) /* update metadata */ chunk->free_bytes += bits * PCPU_MIN_ALLOC_SIZE; + /* update first free bit */ + chunk->first_bit = min(chunk->first_bit, bit_off); + pcpu_block_update_hint_free(chunk, bit_off, bits); pcpu_chunk_relocate(chunk, oslot); @@ -841,6 +852,8 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, set_bit(0, chunk->bound_map); set_bit(offset_bits, chunk->bound_map); + chunk->first_bit = offset_bits; + pcpu_block_update_hint_alloc(chunk, 0, offset_bits); } -- cgit v1.2.3-58-ga151