diff options
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 209 |
1 files changed, 205 insertions, 4 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index f3fe7bc7378f..17db527ee2e2 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1190,6 +1190,19 @@ size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, return pcpu_unit_size; } +static size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep) +{ + size_t size_sum; + + size_sum = PFN_ALIGN(static_size + reserved_size + + (*dyn_sizep >= 0 ? *dyn_sizep : 0)); + if (*dyn_sizep != 0) + *dyn_sizep = size_sum - static_size - reserved_size; + + return size_sum; +} + /* * Embedding first chunk setup helper. */ @@ -1241,10 +1254,7 @@ ssize_t __init pcpu_embed_first_chunk(size_t static_size, size_t reserved_size, unsigned int cpu; /* determine parameters and allocate */ - pcpue_size = PFN_ALIGN(static_size + reserved_size + - (dyn_size >= 0 ? dyn_size : 0)); - if (dyn_size != 0) - dyn_size = pcpue_size - static_size - reserved_size; + pcpue_size = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size); pcpue_unit_size = max_t(size_t, pcpue_size, PCPU_MIN_UNIT_SIZE); chunk_size = pcpue_unit_size * num_possible_cpus(); @@ -1391,6 +1401,197 @@ out_free_ar: } /* + * Large page remapping first chunk setup helper + */ +#ifdef CONFIG_NEED_MULTIPLE_NODES +struct pcpul_ent { + unsigned int cpu; + void *ptr; +}; + +static size_t pcpul_size; +static size_t pcpul_unit_size; +static struct pcpul_ent *pcpul_map; +static struct vm_struct pcpul_vm; + +static struct page * __init pcpul_get_page(unsigned int cpu, int pageno) +{ + size_t off = (size_t)pageno << PAGE_SHIFT; + + if (off >= pcpul_size) + return NULL; + + return virt_to_page(pcpul_map[cpu].ptr + off); +} + +/** + * pcpu_lpage_first_chunk - remap the first percpu chunk using large page + * @static_size: the size of static percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes + * @dyn_size: free size for dynamic allocation in bytes, -1 for auto + * @lpage_size: the size of a large page + * @alloc_fn: function to allocate percpu lpage, always called with lpage_size + * @free_fn: function to free percpu memory, @size <= lpage_size + * @map_fn: function to map percpu lpage, always called with lpage_size + * + * This allocator uses large page as unit. A large page is allocated + * for each cpu and each is remapped into vmalloc area using large + * page mapping. As large page can be quite large, only part of it is + * used for the first chunk. Unused part is returned to the bootmem + * allocator. + * + * So, the large pages are mapped twice - once to the physical mapping + * and to the vmalloc area for the first percpu chunk. The double + * mapping does add one more large TLB entry pressure but still is + * much better than only using 4k mappings while still being NUMA + * friendly. + * + * RETURNS: + * The determined pcpu_unit_size which can be used to initialize + * percpu access on success, -errno on failure. + */ +ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size, + ssize_t dyn_size, size_t lpage_size, + pcpu_fc_alloc_fn_t alloc_fn, + pcpu_fc_free_fn_t free_fn, + pcpu_fc_map_fn_t map_fn) +{ + size_t size_sum; + size_t map_size; + unsigned int cpu; + int i, j; + ssize_t ret; + + /* + * Currently supports only single page. Supporting multiple + * pages won't be too difficult if it ever becomes necessary. + */ + size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, &dyn_size); + + pcpul_unit_size = lpage_size; + pcpul_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); + if (pcpul_size > pcpul_unit_size) { + pr_warning("PERCPU: static data is larger than large page, " + "can't use large page\n"); + return -EINVAL; + } + + /* allocate pointer array and alloc large pages */ + map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0])); + pcpul_map = alloc_bootmem(map_size); + + for_each_possible_cpu(cpu) { + void *ptr; + + ptr = alloc_fn(cpu, lpage_size); + if (!ptr) { + pr_warning("PERCPU: failed to allocate large page " + "for cpu%u\n", cpu); + goto enomem; + } + + /* + * Only use pcpul_size bytes and give back the rest. + * + * Ingo: The lpage_size up-rounding bootmem is needed + * to make sure the partial lpage is still fully RAM - + * it's not well-specified to have a incompatible area + * (unmapped RAM, device memory, etc.) in that hole. + */ + free_fn(ptr + pcpul_size, lpage_size - pcpul_size); + + pcpul_map[cpu].cpu = cpu; + pcpul_map[cpu].ptr = ptr; + + memcpy(ptr, __per_cpu_load, static_size); + } + + /* allocate address and map */ + pcpul_vm.flags = VM_ALLOC; + pcpul_vm.size = num_possible_cpus() * pcpul_unit_size; + vm_area_register_early(&pcpul_vm, pcpul_unit_size); + + for_each_possible_cpu(cpu) + map_fn(pcpul_map[cpu].ptr, pcpul_unit_size, + pcpul_vm.addr + cpu * pcpul_unit_size); + + /* we're ready, commit */ + pr_info("PERCPU: Remapped at %p with large pages, static data " + "%zu bytes\n", pcpul_vm.addr, static_size); + + ret = pcpu_setup_first_chunk(pcpul_get_page, static_size, + reserved_size, dyn_size, pcpul_unit_size, + pcpul_vm.addr, NULL); + + /* sort pcpul_map array for pcpu_lpage_remapped() */ + for (i = 0; i < num_possible_cpus() - 1; i++) + for (j = i + 1; j < num_possible_cpus(); j++) + if (pcpul_map[i].ptr > pcpul_map[j].ptr) { + struct pcpul_ent tmp = pcpul_map[i]; + pcpul_map[i] = pcpul_map[j]; + pcpul_map[j] = tmp; + } + + return ret; + +enomem: + for_each_possible_cpu(cpu) + if (pcpul_map[cpu].ptr) + free_fn(pcpul_map[cpu].ptr, pcpul_size); + free_bootmem(__pa(pcpul_map), map_size); + return -ENOMEM; +} + +/** + * pcpu_lpage_remapped - determine whether a kaddr is in pcpul recycled area + * @kaddr: the kernel address in question + * + * Determine whether @kaddr falls in the pcpul recycled area. This is + * used by pageattr to detect VM aliases and break up the pcpu large + * page mapping such that the same physical page is not mapped under + * different attributes. + * + * The recycled area is always at the tail of a partially used large + * page. + * + * RETURNS: + * Address of corresponding remapped pcpu address if match is found; + * otherwise, NULL. + */ +void *pcpu_lpage_remapped(void *kaddr) +{ + unsigned long unit_mask = pcpul_unit_size - 1; + void *lpage_addr = (void *)((unsigned long)kaddr & ~unit_mask); + unsigned long offset = (unsigned long)kaddr & unit_mask; + int left = 0, right = num_possible_cpus() - 1; + int pos; + + /* pcpul in use at all? */ + if (!pcpul_map) + return NULL; + + /* okay, perform binary search */ + while (left <= right) { + pos = (left + right) / 2; + + if (pcpul_map[pos].ptr < lpage_addr) + left = pos + 1; + else if (pcpul_map[pos].ptr > lpage_addr) + right = pos - 1; + else { + /* it shouldn't be in the area for the first chunk */ + WARN_ON(offset < pcpul_size); + + return pcpul_vm.addr + + pcpul_map[pos].cpu * pcpul_unit_size + offset; + } + } + + return NULL; +} +#endif + +/* * Generic percpu area setup. * * The embedding helper is used because its behavior closely resembles |