diff options
| -rw-r--r-- | mm/percpu-km.c | 2 | ||||
| -rw-r--r-- | mm/percpu.c | 122 |
2 files changed, 114 insertions, 10 deletions
diff --git a/mm/percpu-km.c b/mm/percpu-km.c index e662b49..10e3d0b 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); - bitmap_fill(chunk->populated, nr_pages); + pcpu_chunk_populated(chunk, 0, nr_pages); spin_unlock_irq(&pcpu_lock); return chunk; diff --git a/mm/percpu.c b/mm/percpu.c index 546ced0..4f2d587 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -113,6 +113,7 @@ struct pcpu_chunk { void *data; /* chunk data */ int first_free; /* no free below this */ bool immutable; /* no [de]population allowed */ + int nr_populated; /* # of populated pages */ unsigned long populated[]; /* populated bitmap */ }; @@ -161,6 +162,12 @@ static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */ static struct list_head *pcpu_slot __read_mostly; /* chunk list slots */ +/* + * The number of empty populated pages, protected by pcpu_lock. The + * reserved chunk doesn't contribute to the count. + */ +static int pcpu_nr_empty_pop_pages; + /* reclaim work to release fully free chunks, scheduled from free path */ static void pcpu_reclaim(struct work_struct *work); static DECLARE_WORK(pcpu_reclaim_work, pcpu_reclaim); @@ -296,6 +303,38 @@ static void pcpu_mem_free(void *ptr, size_t size) } /** + * 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 @@ -483,6 +522,7 @@ static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size, * @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 @@ -498,7 +538,7 @@ static int pcpu_fit_in_area(struct pcpu_chunk *chunk, int off, int this_size, * found. */ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align, - bool pop_only) + bool pop_only, int *occ_pages_p) { int oslot = pcpu_chunk_slot(chunk); int max_contig = 0; @@ -587,6 +627,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align, chunk->free_size -= size; *p |= 1; + *occ_pages_p = pcpu_count_occupied_pages(chunk, i); pcpu_chunk_relocate(chunk, oslot); return off; } @@ -602,6 +643,7 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align, * pcpu_free_area - free area to a pcpu_chunk * @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 @@ -610,7 +652,8 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int size, int align, * CONTEXT: * pcpu_lock. */ -static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) +static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme, + int *occ_pages_p) { int oslot = pcpu_chunk_slot(chunk); int off = 0; @@ -641,6 +684,8 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int freeme) *p = off &= ~1; chunk->free_size += (p[1] & ~1) - off; + *occ_pages_p = pcpu_count_occupied_pages(chunk, i); + /* merge with next? */ if (!(p[1] & 1)) to_free++; @@ -696,6 +741,50 @@ static void pcpu_free_chunk(struct pcpu_chunk *chunk) pcpu_mem_free(chunk, pcpu_chunk_struct_size); } +/** + * pcpu_chunk_populated - post-population bookkeeping + * @chunk: pcpu_chunk which got populated + * @page_start: the start page + * @page_end: the end page + * + * Pages in [@page_start,@page_end) have been populated to @chunk. Update + * the bookkeeping information accordingly. Must be called after each + * successful population. + */ +static void pcpu_chunk_populated(struct pcpu_chunk *chunk, + int page_start, int page_end) +{ + int nr = page_end - page_start; + + lockdep_assert_held(&pcpu_lock); + + bitmap_set(chunk->populated, page_start, nr); + chunk->nr_populated += nr; + pcpu_nr_empty_pop_pages += nr; +} + +/** + * pcpu_chunk_depopulated - post-depopulation bookkeeping + * @chunk: pcpu_chunk which got depopulated + * @page_start: the start page + * @page_end: the end page + * + * Pages in [@page_start,@page_end) have been depopulated from @chunk. + * Update the bookkeeping information accordingly. Must be called after + * each successful depopulation. + */ +static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk, + int page_start, int page_end) +{ + int nr = page_end - page_start; + + lockdep_assert_held(&pcpu_lock); + + bitmap_clear(chunk->populated, page_start, nr); + chunk->nr_populated -= nr; + pcpu_nr_empty_pop_pages -= nr; +} + /* * Chunk management implementation. * @@ -772,6 +861,7 @@ 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); + int occ_pages = 0; int slot, off, new_alloc, cpu, ret; unsigned long flags; void __percpu *ptr; @@ -812,7 +902,8 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, spin_lock_irqsave(&pcpu_lock, flags); } - off = pcpu_alloc_area(chunk, size, align, is_atomic); + off = pcpu_alloc_area(chunk, size, align, is_atomic, + &occ_pages); if (off >= 0) goto area_found; @@ -845,7 +936,8 @@ restart: goto restart; } - off = pcpu_alloc_area(chunk, size, align, is_atomic); + off = pcpu_alloc_area(chunk, size, align, is_atomic, + &occ_pages); if (off >= 0) goto area_found; } @@ -899,17 +991,20 @@ area_found: spin_lock_irqsave(&pcpu_lock, flags); if (ret) { mutex_unlock(&pcpu_alloc_mutex); - pcpu_free_area(chunk, off); + pcpu_free_area(chunk, off, &occ_pages); err = "failed to populate"; goto fail_unlock; } - bitmap_set(chunk->populated, rs, re - rs); + pcpu_chunk_populated(chunk, rs, re); spin_unlock_irqrestore(&pcpu_lock, flags); } mutex_unlock(&pcpu_alloc_mutex); } + if (chunk != pcpu_reserved_chunk) + pcpu_nr_empty_pop_pages -= occ_pages; + /* clear the areas and return address relative to base address */ for_each_possible_cpu(cpu) memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size); @@ -1019,7 +1114,9 @@ static void pcpu_reclaim(struct work_struct *work) pcpu_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) { pcpu_depopulate_chunk(chunk, rs, re); - bitmap_clear(chunk->populated, rs, re - rs); + spin_lock_irq(&pcpu_lock); + pcpu_chunk_depopulated(chunk, rs, re); + spin_unlock_irq(&pcpu_lock); } pcpu_destroy_chunk(chunk); } @@ -1041,7 +1138,7 @@ void free_percpu(void __percpu *ptr) void *addr; struct pcpu_chunk *chunk; unsigned long flags; - int off; + int off, occ_pages; if (!ptr) return; @@ -1055,7 +1152,10 @@ void free_percpu(void __percpu *ptr) chunk = pcpu_chunk_addr_search(addr); off = addr - chunk->base_addr; - pcpu_free_area(chunk, off); + pcpu_free_area(chunk, off, &occ_pages); + + if (chunk != pcpu_reserved_chunk) + pcpu_nr_empty_pop_pages += occ_pages; /* if there are more than one fully free chunks, wake up grim reaper */ if (chunk->free_size == pcpu_unit_size) { @@ -1459,6 +1559,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, schunk->map_alloc = ARRAY_SIZE(smap); schunk->immutable = true; bitmap_fill(schunk->populated, pcpu_unit_pages); + schunk->nr_populated = pcpu_unit_pages; if (ai->reserved_size) { schunk->free_size = ai->reserved_size; @@ -1488,6 +1589,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, dchunk->map_alloc = ARRAY_SIZE(dmap); dchunk->immutable = true; bitmap_fill(dchunk->populated, pcpu_unit_pages); + dchunk->nr_populated = pcpu_unit_pages; dchunk->contig_hint = dchunk->free_size = dyn_size; dchunk->map[0] = 1; @@ -1498,6 +1600,8 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, /* link the first chunk in */ pcpu_first_chunk = dchunk ?: schunk; + pcpu_nr_empty_pop_pages += + pcpu_count_occupied_pages(pcpu_first_chunk, 1); pcpu_chunk_relocate(pcpu_first_chunk, -1); /* we're done */ |
