diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/percpu-internal.h | 34 | ||||
| -rw-r--r-- | mm/percpu-km.c | 2 | ||||
| -rw-r--r-- | mm/percpu-stats.c | 99 | ||||
| -rw-r--r-- | mm/percpu.c | 729 |
4 files changed, 362 insertions, 502 deletions
diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index c4c8fc49780b..2e9d9bcb6fa2 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -11,14 +11,12 @@ struct pcpu_chunk { #endif struct list_head list; /* linked to pcpu_slot lists */ - int free_size; /* free bytes in the chunk */ - int contig_hint; /* max contiguous size hint */ + int free_bytes; /* free bytes in the chunk */ + int contig_bits; /* max contiguous size hint */ void *base_addr; /* base address of this chunk */ - int map_used; /* # of map entries used before the sentry */ - int map_alloc; /* # of map entries allocated */ - int *map; /* allocation map */ - struct list_head map_extend_list;/* on pcpu_map_extend_chunks */ + unsigned long *alloc_map; /* allocation map */ + unsigned long *bound_map; /* boundary map */ void *data; /* chunk data */ int first_free; /* no free below this */ @@ -45,6 +43,30 @@ extern int pcpu_nr_empty_pop_pages; extern struct pcpu_chunk *pcpu_first_chunk; extern struct pcpu_chunk *pcpu_reserved_chunk; +/** + * pcpu_nr_pages_to_map_bits - converts the pages to size of bitmap + * @pages: number of physical pages + * + * This conversion is from physical pages to the number of bits + * required in the bitmap. + */ +static inline int pcpu_nr_pages_to_map_bits(int pages) +{ + return pages * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; +} + +/** + * pcpu_chunk_map_bits - helper to convert nr_pages to size of bitmap + * @chunk: chunk of interest + * + * This conversion is from the number of physical pages that the chunk + * serves to the number of bits in the bitmap. + */ +static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk) +{ + return pcpu_nr_pages_to_map_bits(chunk->nr_pages); +} + #ifdef CONFIG_PERCPU_STATS #include <linux/spinlock.h> diff --git a/mm/percpu-km.c b/mm/percpu-km.c index eb58aa4c0997..d2a76642c4ae 100644 --- a/mm/percpu-km.c +++ b/mm/percpu-km.c @@ -69,7 +69,7 @@ static struct pcpu_chunk *pcpu_create_chunk(void) chunk->base_addr = page_address(pages) - pcpu_group_offsets[0]; spin_lock_irq(&pcpu_lock); - pcpu_chunk_populated(chunk, 0, nr_pages); + pcpu_chunk_populated(chunk, 0, nr_pages, false); spin_unlock_irq(&pcpu_lock); pcpu_stats_chunk_alloc(); diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c index e146b585fd18..ad03d73aa5fe 100644 --- a/mm/percpu-stats.c +++ b/mm/percpu-stats.c @@ -29,65 +29,85 @@ static int cmpint(const void *a, const void *b) } /* - * Iterates over all chunks to find the max # of map entries used. + * Iterates over all chunks to find the max nr_alloc entries. */ -static int find_max_map_used(void) +static int find_max_nr_alloc(void) { struct pcpu_chunk *chunk; - int slot, max_map_used; + int slot, max_nr_alloc; - max_map_used = 0; + max_nr_alloc = 0; for (slot = 0; slot < pcpu_nr_slots; slot++) list_for_each_entry(chunk, &pcpu_slot[slot], list) - max_map_used = max(max_map_used, chunk->map_used); + max_nr_alloc = max(max_nr_alloc, chunk->nr_alloc); - return max_map_used; + return max_nr_alloc; } /* * Prints out chunk state. Fragmentation is considered between * the beginning of the chunk to the last allocation. + * + * All statistics are in bytes unless stated otherwise. */ static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, int *buffer) { - int i, s_index, e_index, last_alloc, alloc_sign, as_len; + int i, last_alloc, as_len, start, end; int *alloc_sizes, *p; /* statistics */ int sum_frag = 0, max_frag = 0; int cur_min_alloc = 0, cur_med_alloc = 0, cur_max_alloc = 0; alloc_sizes = buffer; - s_index = (chunk->start_offset) ? 1 : 0; - e_index = chunk->map_used - ((chunk->end_offset) ? 1 : 0); - - /* find last allocation */ - last_alloc = -1; - for (i = e_index - 1; i >= s_index; i--) { - if (chunk->map[i] & 1) { - last_alloc = i; - break; - } - } - /* if the chunk is not empty - ignoring reserve */ - if (last_alloc >= s_index) { - as_len = last_alloc + 1 - s_index; - - /* - * Iterate through chunk map computing size info. - * The first bit is overloaded to be a used flag. - * negative = free space, positive = allocated - */ - for (i = 0, p = chunk->map + s_index; i < as_len; i++, p++) { - alloc_sign = (*p & 1) ? 1 : -1; - alloc_sizes[i] = alloc_sign * - ((p[1] & ~1) - (p[0] & ~1)); + /* + * find_last_bit returns the start value if nothing found. + * Therefore, we must determine if it is a failure of find_last_bit + * and set the appropriate value. + */ + last_alloc = find_last_bit(chunk->alloc_map, + pcpu_chunk_map_bits(chunk) - + chunk->end_offset / PCPU_MIN_ALLOC_SIZE - 1); + last_alloc = test_bit(last_alloc, chunk->alloc_map) ? + last_alloc + 1 : 0; + + as_len = 0; + start = chunk->start_offset; + + /* + * If a bit is set in the allocation map, the bound_map identifies + * where the allocation ends. If the allocation is not set, the + * bound_map does not identify free areas as it is only kept accurate + * on allocation, not free. + * + * Positive values are allocations and negative values are free + * fragments. + */ + while (start < last_alloc) { + if (test_bit(start, chunk->alloc_map)) { + end = find_next_bit(chunk->bound_map, last_alloc, + start + 1); + alloc_sizes[as_len] = 1; + } else { + end = find_next_bit(chunk->alloc_map, last_alloc, + start + 1); + alloc_sizes[as_len] = -1; } - sort(alloc_sizes, as_len, sizeof(chunk->map[0]), cmpint, NULL); + alloc_sizes[as_len++] *= (end - start) * PCPU_MIN_ALLOC_SIZE; + + start = end; + } + + /* + * The negative values are free fragments and thus sorting gives the + * free fragments at the beginning in largest first order. + */ + if (as_len > 0) { + sort(alloc_sizes, as_len, sizeof(int), cmpint, NULL); - /* Iterate through the unallocated fragements. */ + /* iterate through the unallocated fragments */ for (i = 0, p = alloc_sizes; *p < 0 && i < as_len; i++, p++) { sum_frag -= *p; max_frag = max(max_frag, -1 * (*p)); @@ -101,8 +121,8 @@ 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("free_size", chunk->free_size); - P("contig_hint", chunk->contig_hint); + P("free_bytes", chunk->free_bytes); + P("contig_bytes", chunk->contig_bits * PCPU_MIN_ALLOC_SIZE); P("sum_frag", sum_frag); P("max_frag", max_frag); P("cur_min_alloc", cur_min_alloc); @@ -114,22 +134,23 @@ static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, static int percpu_stats_show(struct seq_file *m, void *v) { struct pcpu_chunk *chunk; - int slot, max_map_used; + int slot, max_nr_alloc; int *buffer; alloc_buffer: spin_lock_irq(&pcpu_lock); - max_map_used = find_max_map_used(); + max_nr_alloc = find_max_nr_alloc(); spin_unlock_irq(&pcpu_lock); - buffer = vmalloc(max_map_used * sizeof(pcpu_first_chunk->map[0])); + /* there can be at most this many free and allocated fragments */ + buffer = vmalloc((2 * max_nr_alloc + 1) * sizeof(int)); if (!buffer) return -ENOMEM; spin_lock_irq(&pcpu_lock); /* if the buffer allocated earlier is too small */ - if (max_map_used < find_max_map_used()) { + if (max_nr_alloc < find_max_nr_alloc()) { spin_unlock_irq(&pcpu_lock); vfree(buffer); goto alloc_buffer; diff --git a/mm/percpu.c b/mm/percpu.c index 84cc2559d4aa..986d900e6680 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -86,10 +86,9 @@ #include "percpu-internal.h" -#define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ -#define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ -#define PCPU_ATOMIC_MAP_MARGIN_LOW 32 -#define PCPU_ATOMIC_MAP_MARGIN_HIGH 64 +/* the slots are sorted by free bytes left, 1-31 bytes share the same slot */ +#define PCPU_SLOT_BASE_SHIFT 5 + #define PCPU_EMPTY_POP_PAGES_LOW 2 #define PCPU_EMPTY_POP_PAGES_HIGH 4 @@ -218,10 +217,10 @@ static int pcpu_size_to_slot(int size) static int pcpu_chunk_slot(const struct pcpu_chunk *chunk) { - if (chunk->free_size < sizeof(int) || chunk->contig_hint < sizeof(int)) + if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || chunk->contig_bits == 0) return 0; - return pcpu_size_to_slot(chunk->free_size); + return pcpu_size_to_slot(chunk->free_bytes); } /* set the pointer to a chunk in a page struct */ @@ -317,38 +316,6 @@ static void pcpu_mem_free(void *ptr) } /** - * pcpu_count_occupied_pages - count the number of pages an area occupies - * @chunk: chunk of interest - * @i: index of the area in question - * - * Count the number of pages chunk's @i'th area occupies. When the area's - * start and/or end address isn't aligned to page boundary, the straddled - * page is included in the count iff the rest of the page is free. - */ -static int pcpu_count_occupied_pages(struct pcpu_chunk *chunk, int i) -{ - int off = chunk->map[i] & ~1; - int end = chunk->map[i + 1] & ~1; - - if (!PAGE_ALIGNED(off) && i > 0) { - int prev = chunk->map[i - 1]; - - if (!(prev & 1) && prev <= round_down(off, PAGE_SIZE)) - off = round_down(off, PAGE_SIZE); - } - - if (!PAGE_ALIGNED(end) && i + 1 < chunk->map_used) { - int next = chunk->map[i + 1]; - int nend = chunk->map[i + 2] & ~1; - - if (!(next & 1) && nend >= round_up(end, PAGE_SIZE)) - end = round_up(end, PAGE_SIZE); - } - - return max_t(int, PFN_DOWN(end) - PFN_UP(off), 0); -} - -/** * pcpu_chunk_relocate - put chunk in the appropriate chunk slot * @chunk: chunk of interest * @oslot: the previous slot it was on @@ -374,358 +341,270 @@ static void pcpu_chunk_relocate(struct pcpu_chunk *chunk, int oslot) } /** - * pcpu_need_to_extend - determine whether chunk area map needs to be extended + * pcpu_cnt_pop_pages- counts populated backing pages in range * @chunk: chunk of interest - * @is_atomic: the allocation context + * @bit_off: start offset + * @bits: size of area to check * - * Determine whether area map of @chunk needs to be extended. If - * @is_atomic, only the amount necessary for a new allocation is - * considered; however, async extension is scheduled if the left amount is - * low. If !@is_atomic, it aims for more empty space. Combined, this - * ensures that the map is likely to have enough available space to - * accomodate atomic allocations which can't extend maps directly. - * - * CONTEXT: - * pcpu_lock. + * Calculates the number of populated pages in the region + * [page_start, page_end). This keeps track of how many empty populated + * pages are available and decide if async work should be scheduled. * * RETURNS: - * New target map allocation length if extension is necessary, 0 - * otherwise. + * The nr of populated pages. */ -static int pcpu_need_to_extend(struct pcpu_chunk *chunk, bool is_atomic) +static inline int pcpu_cnt_pop_pages(struct pcpu_chunk *chunk, int bit_off, + int bits) { - int margin, new_alloc; - - lockdep_assert_held(&pcpu_lock); + int page_start = PFN_UP(bit_off * PCPU_MIN_ALLOC_SIZE); + int page_end = PFN_DOWN((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); - if (is_atomic) { - margin = 3; - - if (chunk->map_alloc < - chunk->map_used + PCPU_ATOMIC_MAP_MARGIN_LOW) { - if (list_empty(&chunk->map_extend_list)) { - list_add_tail(&chunk->map_extend_list, - &pcpu_map_extend_chunks); - pcpu_schedule_balance_work(); - } - } - } else { - margin = PCPU_ATOMIC_MAP_MARGIN_HIGH; - } - - if (chunk->map_alloc >= chunk->map_used + margin) + if (page_start >= page_end) return 0; - new_alloc = PCPU_DFL_MAP_ALLOC; - while (new_alloc < chunk->map_used + margin) - new_alloc *= 2; - - return new_alloc; + /* + * bitmap_weight counts the number of bits set in a bitmap up to + * the specified number of bits. This is counting the populated + * pages up to page_end and then subtracting the populated pages + * up to page_start to count the populated pages in + * [page_start, page_end). + */ + return bitmap_weight(chunk->populated, page_end) - + bitmap_weight(chunk->populated, page_start); } /** - * pcpu_extend_area_map - extend area map of a chunk + * pcpu_chunk_update - updates the chunk metadata given a free area * @chunk: chunk of interest - * @new_alloc: new target allocation length of the area map + * @bit_off: chunk offset + * @bits: size of free area * - * Extend area map of @chunk to have @new_alloc entries. + * This updates the chunk's contig hint given a free area. + */ +static void pcpu_chunk_update(struct pcpu_chunk *chunk, int bit_off, int bits) +{ + if (bits > chunk->contig_bits) + chunk->contig_bits = bits; +} + +/** + * pcpu_chunk_refresh_hint - updates metadata about a chunk + * @chunk: chunk of interest * - * CONTEXT: - * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock. + * Iterates over the chunk to find the largest free area. * - * RETURNS: - * 0 on success, -errno on failure. + * Updates: + * chunk->contig_bits + * nr_empty_pop_pages */ -static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc) +static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) { - int *old = NULL, *new = NULL; - size_t old_size = 0, new_size = new_alloc * sizeof(new[0]); - unsigned long flags; + int bits, nr_empty_pop_pages; + int rs, re; /* region start, region end */ - lockdep_assert_held(&pcpu_alloc_mutex); + /* clear metadata */ + chunk->contig_bits = 0; - new = pcpu_mem_zalloc(new_size); - if (!new) - return -ENOMEM; + bits = nr_empty_pop_pages = 0; + pcpu_for_each_unpop_region(chunk->alloc_map, rs, re, 0, + pcpu_chunk_map_bits(chunk)) { + bits = re - rs; - /* acquire pcpu_lock and switch to new area map */ - spin_lock_irqsave(&pcpu_lock, flags); + pcpu_chunk_update(chunk, rs, bits); - if (new_alloc <= chunk->map_alloc) - goto out_unlock; + nr_empty_pop_pages += pcpu_cnt_pop_pages(chunk, rs, bits); + } - old_size = chunk->map_alloc * sizeof(chunk->map[0]); - old = chunk->map; + /* + * Keep track of nr_empty_pop_pages. + * + * The chunk maintains the previous number of free pages it held, + * so the delta is used to update the global counter. The reserved + * chunk is not part of the free page count as they are populated + * at init and are special to serving reserved allocations. + */ + if (chunk != pcpu_reserved_chunk) + pcpu_nr_empty_pop_pages += + (nr_empty_pop_pages - chunk->nr_empty_pop_pages); - memcpy(new, old, old_size); + chunk->nr_empty_pop_pages = nr_empty_pop_pages; +} - chunk->map_alloc = new_alloc; - chunk->map = new; - new = NULL; +/** + * pcpu_is_populated - determines if the region is populated + * @chunk: chunk of interest + * @bit_off: chunk offset + * @bits: size of area + * @next_off: return value for the next offset to start searching + * + * For atomic allocations, check if the backing pages are populated. + * + * RETURNS: + * Bool if the backing pages are populated. + * next_index is to skip over unpopulated blocks in pcpu_find_block_fit. + */ +static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, + int *next_off) +{ + int page_start, page_end, rs, re; -out_unlock: - spin_unlock_irqrestore(&pcpu_lock, flags); + page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); + page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); - /* - * pcpu_mem_free() might end up calling vfree() which uses - * IRQ-unsafe lock and thus can't be called under pcpu_lock. - */ - pcpu_mem_free(old); - pcpu_mem_free(new); + rs = page_start; + pcpu_next_unpop(chunk->populated, &rs, &re, page_end); + if (rs >= page_end) + return true; - return 0; + *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; + return false; } /** - * pcpu_fit_in_area - try to fit the requested allocation in a candidate area - * @chunk: chunk the candidate area belongs to - * @off: the offset to the start of the candidate area - * @this_size: the size of the candidate area - * @size: the size of the target allocation - * @align: the alignment of the target allocation - * @pop_only: only allocate from already populated region - * - * We're trying to allocate @size bytes aligned at @align. @chunk's area - * at @off sized @this_size is a candidate. This function determines - * whether the target allocation fits in the candidate area and returns the - * number of bytes to pad after @off. If the target area doesn't fit, -1 - * is returned. - * - * If @pop_only is %true, this function only considers the already - * populated part of the candidate area. + * pcpu_find_block_fit - finds the block index to start searching + * @chunk: chunk of interest + * @alloc_bits: size of request in allocation units + * @align: alignment of area (max PAGE_SIZE bytes) + * @pop_only: use populated regions only + * + * RETURNS: + * The offset in the bitmap to begin searching. + * -1 if no offset is found. */ -static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size, - int size, int align, bool pop_only) +static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, + size_t align, bool pop_only) { - int cand_off = off; + int bit_off, bits; + int re; /* region end */ - while (true) { - int head = ALIGN(cand_off, align) - off; - int page_start, page_end, rs, re; + pcpu_for_each_unpop_region(chunk->alloc_map, bit_off, re, 0, + pcpu_chunk_map_bits(chunk)) { + bits = re - bit_off; - if (this_size < head + size) - return -1; + /* check alignment */ + bits -= ALIGN(bit_off, align) - bit_off; + bit_off = ALIGN(bit_off, align); + if (bits < alloc_bits) + continue; - if (!pop_only) - return head; + bits = alloc_bits; + if (!pop_only || pcpu_is_populated(chunk, bit_off, bits, + &bit_off)) + break; - /* - * If the first unpopulated page is beyond the end of the - * allocation, the whole allocation is populated; - * otherwise, retry from the end of the unpopulated area. - */ - page_start = PFN_DOWN(head + off); - page_end = PFN_UP(head + off + size); - - rs = page_start; - pcpu_next_unpop(chunk->populated, &rs, &re, - PFN_UP(off + this_size)); - if (rs >= page_end) - return head; - cand_off = re * PAGE_SIZE; + bits = 0; } + + if (bit_off == pcpu_chunk_map_bits(chunk)) + return -1; + + return bit_off; } /** - * pcpu_alloc_area - allocate area from a pcpu_chunk + * pcpu_alloc_area - allocates an area from a pcpu_chunk * @chunk: chunk of interest - * @size: wanted size in bytes - * @align: wanted align - * @pop_only: allocate only from the populated area - * @occ_pages_p: out param for the number of pages the area occupies - * - * Try to allocate @size bytes area aligned at @align from @chunk. - * Note that this function only allocates the offset. It doesn't - * populate or map the area. - * - * @chunk->map must have at least two free slots. + * @alloc_bits: size of request in allocation units + * @align: alignment of area (max PAGE_SIZE) + * @start: bit_off to start searching * - * CONTEXT: - * pcpu_lock. + * This function takes in a @start offset to begin searching to fit an + * allocation of @alloc_bits with alignment @align. If it confirms a + * valid free area, it then updates the allocation and boundary maps + * accordingly. * * RETURNS: - * Allocated offset in @chunk on success, -1 if no matching area is - * found. + * Allocated addr offset in @chunk on success. + * -1 if no matching area is found. */ -static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align, - bool pop_only, int *occ_pages_p) +static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, + size_t align, int start) { - int oslot = pcpu_chunk_slot(chunk); - int max_contig = 0; - int i, off; - bool seen_free = false; - int *p; - - for (i = chunk->first_free, p = chunk->map + i; i < chunk->map_used; i++, p++) { - int head, tail; - int this_size; - - off = *p; - if (off & 1) - continue; - - this_size = (p[1] & ~1) - off; + size_t align_mask = (align) ? (align - 1) : 0; + int bit_off, end, oslot; - head = pcpu_fit_in_area(chunk, off, this_size, size, align, - pop_only); - if (head < 0) { - if (!seen_free) { - chunk->first_free = i; - seen_free = true; - } - max_contig = max(this_size, max_contig); - continue; - } - - /* - * If head is small or the previous block is free, - * merge'em. Note that 'small' is defined as smaller - * than sizeof(int), which is very small but isn't too - * uncommon for percpu allocations. - */ - if (head && (head < sizeof(int) || !(p[-1] & 1))) { - *p = off += head; - if (p[-1] & 1) - chunk->free_size -= head; - else - max_contig = max(*p - p[-1], max_contig); - this_size -= head; - head = 0; - } + lockdep_assert_held(&pcpu_lock); - /* if tail is small, just keep it around */ - tail = this_size - head - size; - if (tail < sizeof(int)) { - tail = 0; - size = this_size - head; - } + oslot = pcpu_chunk_slot(chunk); - /* split if warranted */ - if (head || tail) { - int nr_extra = !!head + !!tail; - - /* insert new subblocks */ - memmove(p + nr_extra + 1, p + 1, - sizeof(chunk->map[0]) * (chunk->map_used - i)); - chunk->map_used += nr_extra; - - if (head) { - if (!seen_free) { - chunk->first_free = i; - seen_free = true; - } - *++p = off += head; - ++i; - max_contig = max(head, max_contig); - } - if (tail) { - p[1] = off + size; - max_contig = max(tail, max_contig); - } - } + /* + * Search to find a fit. + */ + end = start + alloc_bits; + bit_off = bitmap_find_next_zero_area(chunk->alloc_map, end, start, + alloc_bits, align_mask); + if (bit_off >= end) + return -1; - if (!seen_free) - chunk->first_free = i + 1; + /* update alloc map */ + bitmap_set(chunk->alloc_map, bit_off, alloc_bits); - /* update hint and mark allocated */ - if (i + 1 == chunk->map_used) - chunk->contig_hint = max_contig; /* fully scanned */ - else - chunk->contig_hint = max(chunk->contig_hint, - max_contig); + /* update boundary map */ + set_bit(bit_off, chunk->bound_map); + bitmap_clear(chunk->bound_map, bit_off + 1, alloc_bits - 1); + set_bit(bit_off + alloc_bits, chunk->bound_map); - chunk->free_size -= size; - *p |= 1; + chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE; - *occ_pages_p = pcpu_count_occupied_pages(chunk, i); - pcpu_chunk_relocate(chunk, oslot); - return off; - } + pcpu_chunk_refresh_hint(chunk); - chunk->contig_hint = max_contig; /* fully scanned */ pcpu_chunk_relocate(chunk, oslot); - /* tell the upper layer that this chunk has no matching area */ - return -1; + return bit_off * PCPU_MIN_ALLOC_SIZE; } /** - * pcpu_free_area - free area to a pcpu_chunk + * pcpu_free_area - frees the corresponding offset * @chunk: chunk of interest - * @freeme: offset of area to free - * @occ_pages_p: out param for the number of pages the area occupies - * - * Free area starting from @freeme to @chunk. Note that this function - * only modifies the allocation map. It doesn't depopulate or unmap - * the area. + * @off: addr offset into chunk * - * CONTEXT: - * pcpu_lock. + * This function determines the size of an allocation to free using + * the boundary bitmap and clears the allocation map. */ -static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme, - int *occ_pages_p) +static void pcpu_free_area(struct pcpu_chunk *chunk, int off) { - int oslot = pcpu_chunk_slot(chunk); - int off = 0; - unsigned i, j; - int to_free = 0; - int *p; + int bit_off, bits, end, oslot; lockdep_assert_held(&pcpu_lock); pcpu_stats_area_dealloc(chunk); - freeme |= 1; /* we are searching for <given offset, in use> pair */ - - i = 0; - j = chunk->map_used; - while (i != j) { - unsigned k = (i + j) / 2; - off = chunk->map[k]; - if (off < freeme) - i = k + 1; - else if (off > freeme) - j = k; - else - i = j = k; - } - BUG_ON(off != freeme); + oslot = pcpu_chunk_slot(chunk); - if (i < chunk->first_free) - chunk->first_free = i; + bit_off = off / PCPU_MIN_ALLOC_SIZE; - p = chunk->map + i; - *p = off &= ~1; - chunk->free_size += (p[1] & ~1) - off; + /* find end index */ + end = find_next_bit(chunk->bound_map, pcpu_chunk_map_bits(chunk), + bit_off + 1); + bits = end - bit_off; + bitmap_clear(chunk->alloc_map, bit_off, bits); - *occ_pages_p = pcpu_count_occupied_pages(chunk, i); + /* update metadata */ + chunk->free_bytes += bits * PCPU_MIN_ALLOC_SIZE; - /* merge with next? */ - if (!(p[1] & 1)) - to_free++; - /* merge with previous? */ - if (i > 0 && !(p[-1] & 1)) { - to_free++; - i--; - p--; - } - if (to_free) { - chunk->map_used -= to_free; - memmove(p + 1, p + 1 + to_free, - (chunk->map_used - i) * sizeof(chunk->map[0])); - } + pcpu_chunk_refresh_hint(chunk); - chunk->contig_hint = max(chunk->map[i + 1] - chunk->map[i] - 1, chunk->contig_hint); pcpu_chunk_relocate(chunk, oslot); } +/** + * pcpu_alloc_first_chunk - creates chunks that serve the first chunk + * @tmp_addr: the start of the region served + * @map_size: size of the region served + * + * This is responsible for creating the chunks that serve the first chunk. The + * base_addr is page aligned down of @tmp_addr while the region end is page + * aligned up. Offsets are kept track of to determine the region served. All + * this is done to appease the bitmap allocator in avoiding partial blocks. + * + * RETURNS: + * Chunk serving the region at @tmp_addr of @map_size. + */ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, - int map_size, - int *map, - int init_map_size) + int map_size) { struct pcpu_chunk *chunk; unsigned long aligned_addr; - int start_offset, region_size; + int start_offset, offset_bits, region_size, region_bits; /* region calculations */ aligned_addr = tmp_addr & PAGE_MASK; @@ -740,83 +619,99 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, 0); INIT_LIST_HEAD(&chunk->list); - INIT_LIST_HEAD(&chunk->map_extend_list); chunk->base_addr = (void *)aligned_addr; chunk->start_offset = start_offset; chunk->end_offset = region_size - chunk->start_offset - map_size; chunk->nr_pages = region_size >> PAGE_SHIFT; + region_bits = pcpu_chunk_map_bits(chunk); - chunk->map = map; - chunk->map_alloc = init_map_size; + chunk->alloc_map = memblock_virt_alloc( + BITS_TO_LONGS(region_bits) * + sizeof(chunk->alloc_map[0]), 0); + chunk->bound_map = memblock_virt_alloc( + BITS_TO_LONGS(region_bits + 1) * + sizeof(chunk->bound_map[0]), 0); /* manage populated page bitmap */ chunk->immutable = true; bitmap_fill(chunk->populated, chunk->nr_pages); chunk->nr_populated = chunk->nr_pages; - chunk->nr_empty_pop_pages = chunk->nr_pages; + chunk->nr_empty_pop_pages = + pcpu_cnt_pop_pages(chunk, start_offset / PCPU_MIN_ALLOC_SIZE, + map_size / PCPU_MIN_ALLOC_SIZE); - chunk->contig_hint = chunk->free_size = map_size; + chunk->contig_bits = map_size / PCPU_MIN_ALLOC_SIZE; + chunk->free_bytes = map_size; if (chunk->start_offset) { /* hide the beginning of the bitmap */ - chunk->nr_empty_pop_pages--; - - chunk->map[0] = 1; - chunk->map[1] = chunk->start_offset; - chunk->map_used = 1; + offset_bits = chunk->start_offset / PCPU_MIN_ALLOC_SIZE; + bitmap_set(chunk->alloc_map, 0, offset_bits); + set_bit(0, chunk->bound_map); + set_bit(offset_bits, chunk->bound_map); } - /* set chunk's free region */ - chunk->map[++chunk->map_used] = - (chunk->start_offset + chunk->free_size) | 1; - if (chunk->end_offset) { /* hide the end of the bitmap */ - chunk->nr_empty_pop_pages--; - - chunk->map[++chunk->map_used] = region_size | 1; + offset_bits = chunk->end_offset / PCPU_MIN_ALLOC_SIZE; + bitmap_set(chunk->alloc_map, + pcpu_chunk_map_bits(chunk) - offset_bits, + offset_bits); + set_bit((start_offset + map_size) / PCPU_MIN_ALLOC_SIZE, + chunk->bound_map); + set_bit(region_bits, chunk->bound_map); } + pcpu_chunk_refresh_hint(chunk); + return chunk; } static struct pcpu_chunk *pcpu_alloc_chunk(void) { struct pcpu_chunk *chunk; + int region_bits; chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size); if (!chunk) return NULL; - chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC * - sizeof(chunk->map[0])); - if (!chunk->map) { - pcpu_mem_free(chunk); - return NULL; - } + INIT_LIST_HEAD(&chunk->list); + chunk->nr_pages = pcpu_unit_pages; + region_bits = pcpu_chunk_map_bits(chunk); - chunk->map_alloc = PCPU_DFL_MAP_ALLOC; - chunk->map[0] = 0; - chunk->map[1] = pcpu_unit_size | 1; - chunk->map_used = 1; + chunk->alloc_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits) * + sizeof(chunk->alloc_map[0])); + if (!chunk->alloc_map) + goto alloc_map_fail; - INIT_LIST_HEAD(&chunk->list); - INIT_LIST_HEAD(&chunk->map_extend_list); - chunk->free_size = pcpu_unit_size; - chunk->contig_hint = pcpu_unit_size; + chunk->bound_map = pcpu_mem_zalloc(BITS_TO_LONGS(region_bits + 1) * + sizeof(chunk->bound_map[0])); + if (!chunk->bound_map) + goto bound_map_fail; - chunk->nr_pages = pcpu_unit_pages; + /* init metadata */ + chunk->contig_bits = region_bits; + chunk->free_bytes = chunk->nr_pages * PAGE_SIZE; return chunk; + +bound_map_fail: + pcpu_mem_free(chunk->alloc_map); +alloc_map_fail: + pcpu_mem_free(chunk); + + return NULL; } static void pcpu_free_chunk(struct pcpu_chunk *chunk) { if (!chunk) return; - pcpu_mem_free(chunk->map); + pcpu_mem_free(chunk->bound_map); + pcpu_mem_free(chunk->alloc_map); pcpu_mem_free(chunk); } @@ -825,13 +720,17 @@ static void pcpu_free_chunk(struct pcpu_chunk *chunk) * @chunk: pcpu_chunk which got populated * @page_start: the start page * @page_end: the end page + * @for_alloc: if this is to populate for allocation * * Pages in [@page_start,@page_end) have been populated to @chunk. Update * the bookkeeping information accordingly. Must be called after each * successful population. + * + * If this is @for_alloc, do not increment pcpu_nr_empty_pop_pages because it + * is to serve an allocation in that area. */ -static void pcpu_chunk_populated(struct pcpu_chunk *chunk, - int page_start, int page_end) +static void pcpu_chunk_populated(struct pcpu_chunk *chunk, int page_start, + int page_end, bool for_alloc) { int nr = page_end - page_start; @@ -839,8 +738,11 @@ static void pcpu_chunk_populated(struct pcpu_chunk *chunk, bitmap_set(chunk->populated, page_start, nr); chunk->nr_populated += nr; - chunk->nr_empty_pop_pages += nr; - pcpu_nr_empty_pop_pages += nr; + + if (!for_alloc) { + chunk->nr_empty_pop_pages += nr; + pcpu_nr_empty_pop_pages += nr; + } } /** @@ -945,19 +847,23 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, struct pcpu_chunk *chunk; const char *err; bool is_atomic = (gfp & GFP_KERNEL) != GFP_KERNEL; - int occ_pages = 0; - int slot, off, new_alloc, cpu, ret; + int slot, off, cpu, ret; unsigned long flags; void __percpu *ptr; + size_t bits, bit_align; /* - * We want the lowest bit of offset available for in-use/free - * indicator, so force >= 16bit alignment and make size even. + * There is now a minimum allocation size of PCPU_MIN_ALLOC_SIZE, + * therefore alignment must be a minimum of that many bytes. + * An allocation may have internal fragmentation from rounding up + * of up to PCPU_MIN_ALLOC_SIZE - 1 bytes. */ if (unlikely(align < PCPU_MIN_ALLOC_SIZE)) align = PCPU_MIN_ALLOC_SIZE; size = ALIGN(size, PCPU_MIN_ALLOC_SIZE); + bits = size >> PCPU_MIN_ALLOC_SHIFT; + bit_align = align >> PCPU_MIN_ALLOC_SHIFT; if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE || !is_power_of_2(align))) { @@ -975,23 +881,13 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, if (reserved && pcpu_reserved_chunk) { chunk = pcpu_reserved_chunk; - if (size > chunk->contig_hint) { + off = pcpu_find_block_fit(chunk, bits, bit_align, is_atomic); + if (off < 0) { err = "alloc from reserved chunk failed"; goto fail_unlock; } - while ((new_alloc = pcpu_need_to_extend(chunk, is_atomic))) { - spin_unlock_irqrestore(&pcpu_lock, flags); - if (is_atomic || - pcpu_extend_area_map(chunk, new_alloc) < 0) { - err = "failed to extend area map of reserved chunk"; - goto fail; - } - spin_lock_irqsave(&pcpu_lock, flags); - } - - off = pcpu_alloc_area(chunk, size, align, is_atomic, - &occ_pages); + off = pcpu_alloc_area(chunk, bits, bit_align, off); if (off >= 0) goto area_found; @@ -1003,31 +899,15 @@ restart: /* search through normal chunks */ for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) { list_for_each_entry(chunk, &pcpu_slot[slot], list) { - if (size > chunk->contig_hint) + off = pcpu_find_block_fit(chunk, bits, bit_align, + is_atomic); + if (off < 0) continue; - new_alloc = pcpu_need_to_extend(chunk, is_atomic); - if (new_alloc) { - if (is_atomic) - continue; - spin_unlock_irqrestore(&pcpu_lock, flags); - if (pcpu_extend_area_map(chunk, - new_alloc) < 0) { - err = "failed to extend area map"; - goto fail; - } - spin_lock_irqsave(&pcpu_lock, flags); - /* - * pcpu_lock has been dropped, need to - * restart cpu_slot list walking. - */ - goto restart; - } - - off = pcpu_alloc_area(chunk, size, align, is_atomic, - &occ_pages); + off = pcpu_alloc_area(chunk, bits, bit_align, off); if (off >= 0) goto area_found; + } } @@ -1077,23 +957,17 @@ area_found: spin_lock_irqsave(&pcpu_lock, flags); if (ret) { - pcpu_free_area(chunk, off, &occ_pages); + pcpu_free_area(chunk, off); err = "failed to populate"; goto fail_unlock; } - pcpu_chunk_populated(chunk, rs, re); + pcpu_chunk_populated(chunk, rs, re, true); spin_unlock_irqrestore(&pcpu_lock, flags); } mutex_unlock(&pcpu_alloc_mutex); } - if (chunk != pcpu_reserved_chunk) { - spin_lock_irqsave(&pcpu_lock, flags); - pcpu_nr_empty_pop_pages -= occ_pages; - spin_unlock_irqrestore(&pcpu_lock, flags); - } - if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW) pcpu_schedule_balance_work(); @@ -1211,7 +1085,6 @@ static void pcpu_balance_workfn(struct work_struct *work) if (chunk == list_first_entry(free_head, struct pcpu_chunk, list)) continue; - list_del_init(&chunk->map_extend_list); list_move(&chunk->list, &to_free); } @@ -1230,25 +1103,6 @@ static void pcpu_balance_workfn(struct work_struct *work) pcpu_destroy_chunk(chunk); } - /* service chunks which requested async area map extension */ - do { - int new_alloc = 0; - - spin_lock_irq(&pcpu_lock); - - chunk = list_first_entry_or_null(&pcpu_map_extend_chunks, - struct pcpu_chunk, map_extend_list); - if (chunk) { - list_del_init(&chunk->map_extend_list); - new_alloc = pcpu_need_to_extend(chunk, false); - } - - spin_unlock_irq(&pcpu_lock); - - if (new_alloc) - pcpu_extend_area_map(chunk, new_alloc); - } while (chunk); - /* * Ensure there are certain number of free populated pages for * atomic allocs. Fill up from the most packed so that atomic @@ -1296,7 +1150,7 @@ retry_pop: if (!ret) { nr_to_pop -= nr; spin_lock_irq(&pcpu_lock); - pcpu_chunk_populated(chunk, rs, rs + nr); + pcpu_chunk_populated(chunk, rs, rs + nr, false); spin_unlock_irq(&pcpu_lock); } else { nr_to_pop = 0; @@ -1335,7 +1189,7 @@ void free_percpu(void __percpu *ptr) void *addr; struct pcpu_chunk *chunk; unsigned long flags; - int off, occ_pages; + int off; if (!ptr) return; @@ -1349,13 +1203,10 @@ void free_percpu(void __percpu *ptr) chunk = pcpu_chunk_addr_search(addr); off = addr - chunk->base_addr; - pcpu_free_area(chunk, off, &occ_pages); - - if (chunk != pcpu_reserved_chunk) - pcpu_nr_empty_pop_pages += occ_pages; + pcpu_free_area(chunk, off); /* if there are more than one fully free chunks, wake up grim reaper */ - if (chunk->free_size == pcpu_unit_size) { + if (chunk->free_bytes == pcpu_unit_size) { struct pcpu_chunk *pos; list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list) @@ -1651,8 +1502,6 @@ static void pcpu_dump_alloc_info(const char *lvl, int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, void *base_addr) { - static int smap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata; - static int dmap[PERCPU_DYNAMIC_EARLY_SLOTS] __initdata; size_t size_sum = ai->static_size + ai->reserved_size + ai->dyn_size; size_t static_size, dyn_size; struct pcpu_chunk *chunk; @@ -1787,8 +1636,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, */ tmp_addr = (unsigned long)base_addr + static_size; map_size = ai->reserved_size ?: dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size, smap, - ARRAY_SIZE(smap)); + chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); /* init dynamic chunk if necessary */ if (ai->reserved_size) { @@ -1797,8 +1645,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, tmp_addr = (unsigned long)base_addr + static_size + ai->reserved_size; map_size = dyn_size; - chunk = pcpu_alloc_first_chunk(tmp_addr, map_size, dmap, - ARRAY_SIZE(dmap)); + chunk = pcpu_alloc_first_chunk(tmp_addr, map_size); } /* link the first chunk in */ @@ -2375,36 +2222,6 @@ void __init setup_per_cpu_areas(void) #endif /* CONFIG_SMP */ /* - * First and reserved chunks are initialized with temporary allocation - * map in initdata so that they can be used before slab is online. - * This function is called after slab is brought up and replaces those - * with properly allocated maps. - */ -void __init percpu_init_late(void) -{ - struct pcpu_chunk *target_chunks[] = - { pcpu_first_chunk, pcpu_reserved_chunk, NULL }; - struct pcpu_chunk *chunk; - unsigned long flags; - int i; - - for (i = 0; (chunk = target_chunks[i]); i++) { - int *map; - const size_t size = PERCPU_DYNAMIC_EARLY_SLOTS * sizeof(map[0]); - - BUILD_BUG_ON(size > PAGE_SIZE); - - map = pcpu_mem_zalloc(size); - BUG_ON(!map); - - spin_lock_irqsave(&pcpu_lock, flags); - memcpy(map, chunk->map, size); - chunk->map = map; - spin_unlock_irqrestore(&pcpu_lock, flags); - } -} - -/* * Percpu allocator is initialized early during boot when neither slab or * workqueue is available. Plug async management until everything is up * and running. |