From 92c14cab43267411bc9160f23d55a7548d814483 Mon Sep 17 00:00:00 2001 From: Dennis Zhou Date: Tue, 26 Feb 2019 10:00:08 -0800 Subject: [PATCH] percpu: convert chunk hints to be based on pcpu_block_md As mentioned in the last patch, a chunk's hints are no different than a block just responsible for more bits. This converts chunk level hints to use a pcpu_block_md to maintain them. This lets us reuse the same hint helper functions as a block. The left_free and right_free are unused by the chunk's pcpu_block_md. Signed-off-by: Dennis Zhou Reviewed-by: Peng Fan --- mm/percpu-internal.h | 5 +- mm/percpu-stats.c | 5 +- mm/percpu.c | 120 +++++++++++++++++++------------------------ 3 files changed, 57 insertions(+), 73 deletions(-) diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index 119bd1119aa7..0468ba500bd4 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -39,9 +39,7 @@ struct pcpu_chunk { struct list_head list; /* linked to pcpu_slot lists */ int free_bytes; /* free bytes in the chunk */ - int contig_bits; /* max contiguous size hint */ - int contig_bits_start; /* contig_bits starting - offset */ + struct pcpu_block_md chunk_md; void *base_addr; /* base address of this chunk */ unsigned long *alloc_map; /* allocation map */ @@ -49,7 +47,6 @@ struct pcpu_chunk { struct pcpu_block_md *md_blocks; /* metadata blocks */ void *data; /* chunk data */ - int first_bit; /* no free below this */ bool immutable; /* no [de]population allowed */ int start_offset; /* the overlap with the previous region to have a page aligned diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c index b5fdd43b60c9..ef5034a0464e 100644 --- a/mm/percpu-stats.c +++ b/mm/percpu-stats.c @@ -53,6 +53,7 @@ static int find_max_nr_alloc(void) static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, int *buffer) { + struct pcpu_block_md *chunk_md = &chunk->chunk_md; int i, last_alloc, as_len, start, end; int *alloc_sizes, *p; /* statistics */ @@ -121,9 +122,9 @@ static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, P("nr_alloc", chunk->nr_alloc); P("max_alloc_size", chunk->max_alloc_size); P("empty_pop_pages", chunk->nr_empty_pop_pages); - P("first_bit", chunk->first_bit); + P("first_bit", chunk_md->first_free); P("free_bytes", chunk->free_bytes); - P("contig_bytes", chunk->contig_bits * PCPU_MIN_ALLOC_SIZE); + P("contig_bytes", chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE); P("sum_frag", sum_frag); P("max_frag", max_frag); P("cur_min_alloc", cur_min_alloc); diff --git a/mm/percpu.c b/mm/percpu.c index acc72d37a830..daebf7a5343c 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -233,10 +233,13 @@ static int pcpu_size_to_slot(int size) static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) { - if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || chunk->contig_bits == 0) + const struct pcpu_block_md *chunk_md = &chunk->chunk_md; + + if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || + chunk_md->contig_hint == 0) return 0; - return pcpu_size_to_slot(chunk->contig_bits * PCPU_MIN_ALLOC_SIZE); + return pcpu_size_to_slot(chunk_md->contig_hint * PCPU_MIN_ALLOC_SIZE); } /* set the pointer to a chunk in a page struct */ @@ -588,54 +591,6 @@ static inline bool pcpu_region_overlap(int a, int b, int x, int y) return (a < y) && (x < b); } -/** - * pcpu_chunk_update - updates the chunk metadata given a free area - * @chunk: chunk of interest - * @bit_off: chunk offset - * @bits: size of free area - * - * This updates the chunk's contig hint and starting offset given a free area. - * Choose the best starting offset if the contig hint is equal. - */ -static void pcpu_chunk_update(struct pcpu_chunk *chunk, int bit_off, int bits) -{ - if (bits > chunk->contig_bits) { - chunk->contig_bits_start = bit_off; - chunk->contig_bits = bits; - } else if (bits == chunk->contig_bits && chunk->contig_bits_start && - (!bit_off || - __ffs(bit_off) > __ffs(chunk->contig_bits_start))) { - /* use the start with the best alignment */ - chunk->contig_bits_start = bit_off; - } -} - -/** - * pcpu_chunk_refresh_hint - updates metadata about a chunk - * @chunk: chunk of interest - * - * Iterates over the metadata blocks to find the largest contig area. - * It also counts the populated pages and uses the delta to update the - * global count. - * - * Updates: - * chunk->contig_bits - * chunk->contig_bits_start - */ -static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) -{ - int bit_off, bits; - - /* clear metadata */ - chunk->contig_bits = 0; - - bit_off = chunk->first_bit; - bits = 0; - pcpu_for_each_md_free_region(chunk, bit_off, bits) { - pcpu_chunk_update(chunk, bit_off, bits); - } -} - /** * pcpu_block_update - updates a block given a free area * @block: block of interest @@ -749,6 +704,29 @@ static void pcpu_block_update_scan(struct pcpu_chunk *chunk, int bit_off, pcpu_block_update(block, s_off, e_off); } +/** + * pcpu_chunk_refresh_hint - updates metadata about a chunk + * @chunk: chunk of interest + * + * Iterates over the metadata blocks to find the largest contig area. + * It also counts the populated pages and uses the delta to update the + * global count. + */ +static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) +{ + struct pcpu_block_md *chunk_md = &chunk->chunk_md; + int bit_off, bits; + + /* clear metadata */ + chunk_md->contig_hint = 0; + + bit_off = chunk_md->first_free; + bits = 0; + pcpu_for_each_md_free_region(chunk, bit_off, bits) { + pcpu_block_update(chunk_md, bit_off, bit_off + bits); + } +} + /** * pcpu_block_refresh_hint * @chunk: chunk of interest @@ -796,6 +774,7 @@ static void pcpu_block_refresh_hint(struct pcpu_chunk *chunk, int index) static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off, int bits) { + struct pcpu_block_md *chunk_md = &chunk->chunk_md; int nr_empty_pages = 0; struct pcpu_block_md *s_block, *e_block, *block; int s_index, e_index; /* block indexes of the freed allocation */ @@ -906,8 +885,9 @@ static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off, * contig hint is broken. Otherwise, it means a smaller space * was used and therefore the chunk contig hint is still correct. */ - if (pcpu_region_overlap(chunk->contig_bits_start, - chunk->contig_bits_start + chunk->contig_bits, + if (pcpu_region_overlap(chunk_md->contig_hint_start, + chunk_md->contig_hint_start + + chunk_md->contig_hint, bit_off, bit_off + bits)) pcpu_chunk_refresh_hint(chunk); @@ -926,9 +906,10 @@ static void pcpu_block_update_hint_alloc(struct pcpu_chunk *chunk, int bit_off, * * A chunk update is triggered if a page becomes free, a block becomes free, * or the free spans across blocks. This tradeoff is to minimize iterating - * over the block metadata to update chunk->contig_bits. chunk->contig_bits - * may be off by up to a page, but it will never be more than the available - * space. If the contig hint is contained in one block, it will be accurate. + * over the block metadata to update chunk_md->contig_hint. + * chunk_md->contig_hint may be off by up to a page, but it will never be more + * than the available space. If the contig hint is contained in one block, it + * will be accurate. */ static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off, int bits) @@ -1022,8 +1003,9 @@ static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off, if (((end - start) >= PCPU_BITMAP_BLOCK_BITS) || s_index != e_index) pcpu_chunk_refresh_hint(chunk); else - pcpu_chunk_update(chunk, pcpu_block_off_to_off(s_index, start), - end - start); + pcpu_block_update(&chunk->chunk_md, + pcpu_block_off_to_off(s_index, start), + end); } /** @@ -1078,6 +1060,7 @@ static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, size_t align, bool pop_only) { + struct pcpu_block_md *chunk_md = &chunk->chunk_md; int bit_off, bits, next_off; /* @@ -1086,12 +1069,12 @@ static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, * cannot fit in the global hint, there is memory pressure and creating * a new chunk would happen soon. */ - bit_off = ALIGN(chunk->contig_bits_start, align) - - chunk->contig_bits_start; - if (bit_off + alloc_bits > chunk->contig_bits) + bit_off = ALIGN(chunk_md->contig_hint_start, align) - + chunk_md->contig_hint_start; + if (bit_off + alloc_bits > chunk_md->contig_hint) return -1; - bit_off = chunk->first_bit; + bit_off = chunk_md->first_free; bits = 0; pcpu_for_each_fit_region(chunk, alloc_bits, align, bit_off, bits) { if (!pop_only || pcpu_is_populated(chunk, bit_off, bits, @@ -1186,6 +1169,7 @@ again: static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, size_t align, int start) { + struct pcpu_block_md *chunk_md = &chunk->chunk_md; size_t align_mask = (align) ? (align - 1) : 0; unsigned long area_off = 0, area_bits = 0; int bit_off, end, oslot; @@ -1218,8 +1202,8 @@ 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( + if (bit_off == chunk_md->first_free) + chunk_md->first_free = find_next_zero_bit( chunk->alloc_map, pcpu_chunk_map_bits(chunk), bit_off + alloc_bits); @@ -1241,6 +1225,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, */ static void pcpu_free_area(struct pcpu_chunk *chunk, int off) { + struct pcpu_block_md *chunk_md = &chunk->chunk_md; int bit_off, bits, end, oslot; lockdep_assert_held(&pcpu_lock); @@ -1260,7 +1245,7 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int off) chunk->free_bytes += bits * PCPU_MIN_ALLOC_SIZE; /* update first free bit */ - chunk->first_bit = min(chunk->first_bit, bit_off); + chunk_md->first_free = min(chunk_md->first_free, bit_off); pcpu_block_update_hint_free(chunk, bit_off, bits); @@ -1281,6 +1266,9 @@ static void pcpu_init_md_blocks(struct pcpu_chunk *chunk) { struct pcpu_block_md *md_block; + /* init the chunk's block */ + pcpu_init_md_block(&chunk->chunk_md, pcpu_chunk_map_bits(chunk)); + for (md_block = chunk->md_blocks; md_block != chunk->md_blocks + pcpu_chunk_nr_blocks(chunk); md_block++) @@ -1365,7 +1353,6 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, chunk->nr_populated = chunk->nr_pages; chunk->nr_empty_pop_pages = chunk->nr_pages; - chunk->contig_bits = map_size / PCPU_MIN_ALLOC_SIZE; chunk->free_bytes = map_size; if (chunk->start_offset) { @@ -1375,7 +1362,7 @@ 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; + chunk->chunk_md.first_free = offset_bits; pcpu_block_update_hint_alloc(chunk, 0, offset_bits); } @@ -1428,7 +1415,6 @@ static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp) pcpu_init_md_blocks(chunk); /* init metadata */ - chunk->contig_bits = region_bits; chunk->free_bytes = chunk->nr_pages * PAGE_SIZE; return chunk;