^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * mm/percpu-km.c - kernel memory based chunk allocation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2010 SUSE Linux Products GmbH
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Copyright (C) 2010 Tejun Heo <tj@kernel.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Chunks are allocated as a contiguous kernel memory using gfp
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * allocation. This is to be used on nommu architectures.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * To use percpu-km,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * - define CONFIG_NEED_PER_CPU_KM from the arch Kconfig.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * - CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK must not be defined. It's
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * not compatible with PER_CPU_KM. EMBED_FIRST_CHUNK should work
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * fine.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * - NUMA is not supported. When setting up the first chunk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * @cpu_distance_fn should be NULL or report all CPUs to be nearer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * than or at LOCAL_DISTANCE.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) * - It's best if the chunk size is power of two multiple of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * PAGE_SIZE. Because each chunk is allocated as a contiguous
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * kernel memory block using alloc_pages(), memory will be wasted if
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * chunk size is not aligned. percpu-km code will whine about it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #if defined(CONFIG_SMP) && defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) #error "contiguous percpu allocation is incompatible with paged first chunk"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #include <linux/log2.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) int page_start, int page_end, gfp_t gfp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) int page_start, int page_end)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) /* nada */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) static struct pcpu_chunk *pcpu_create_chunk(enum pcpu_chunk_type type,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) gfp_t gfp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) struct pcpu_chunk *chunk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) struct page *pages;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) unsigned long flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) int i;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) chunk = pcpu_alloc_chunk(type, gfp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) if (!chunk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) pages = alloc_pages(gfp, order_base_2(nr_pages));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) if (!pages) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) pcpu_free_chunk(chunk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) for (i = 0; i < nr_pages; i++)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) pcpu_set_page_chunk(nth_page(pages, i), chunk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) chunk->data = pages;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) chunk->base_addr = page_address(pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) spin_lock_irqsave(&pcpu_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) pcpu_chunk_populated(chunk, 0, nr_pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) spin_unlock_irqrestore(&pcpu_lock, flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) pcpu_stats_chunk_alloc();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) trace_percpu_create_chunk(chunk->base_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) return chunk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) static void pcpu_destroy_chunk(struct pcpu_chunk *chunk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) const int nr_pages = pcpu_group_sizes[0] >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) if (!chunk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) pcpu_stats_chunk_dealloc();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) trace_percpu_destroy_chunk(chunk->base_addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) if (chunk->data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) __free_pages(chunk->data, order_base_2(nr_pages));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) pcpu_free_chunk(chunk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) static struct page *pcpu_addr_to_page(void *addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) return virt_to_page(addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) size_t nr_pages, alloc_pages;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) /* all units must be in a single group */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) if (ai->nr_groups != 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) pr_crit("can't handle more than one group\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) nr_pages = (ai->groups[0].nr_units * ai->unit_size) >> PAGE_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) alloc_pages = roundup_pow_of_two(nr_pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) if (alloc_pages > nr_pages)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) pr_warn("wasting %zu pages per chunk\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) alloc_pages - nr_pages);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) }
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
3 Commits
0 Branches
0 Tags