diff options
| -rw-r--r-- | arch/x86/kernel/setup_percpu.c | 72 | ||||
| -rw-r--r-- | include/linux/percpu.h | 24 | ||||
| -rw-r--r-- | mm/percpu.c | 358 |
3 files changed, 359 insertions, 95 deletions
diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c index 4f2e0ac..7501bb1 100644 --- a/arch/x86/kernel/setup_percpu.c +++ b/arch/x86/kernel/setup_percpu.c @@ -149,36 +149,73 @@ static void __init pcpul_map(void *ptr, size_t size, void *addr) set_pmd(pmd, pmd_v); } +static int pcpu_lpage_cpu_distance(unsigned int from, unsigned int to) +{ + if (early_cpu_to_node(from) == early_cpu_to_node(to)) + return LOCAL_DISTANCE; + else + return REMOTE_DISTANCE; +} + static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen) { size_t reserve = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE; + size_t dyn_size = reserve - PERCPU_FIRST_CHUNK_RESERVE; + size_t unit_map_size, unit_size; + int *unit_map; + int nr_units; + ssize_t ret; + + /* on non-NUMA, embedding is better */ + if (!chosen && !pcpu_need_numa()) + return -EINVAL; + + /* need PSE */ + if (!cpu_has_pse) { + pr_warning("PERCPU: lpage allocator requires PSE\n"); + return -EINVAL; + } + /* allocate and build unit_map */ + unit_map_size = num_possible_cpus() * sizeof(int); + unit_map = alloc_bootmem_nopanic(unit_map_size); + if (!unit_map) { + pr_warning("PERCPU: failed to allocate unit_map\n"); + return -ENOMEM; + } + + ret = pcpu_lpage_build_unit_map(static_size, + PERCPU_FIRST_CHUNK_RESERVE, + &dyn_size, &unit_size, PMD_SIZE, + unit_map, pcpu_lpage_cpu_distance); + if (ret < 0) { + pr_warning("PERCPU: failed to build unit_map\n"); + goto out_free; + } + nr_units = ret; + + /* do the parameters look okay? */ if (!chosen) { size_t vm_size = VMALLOC_END - VMALLOC_START; - size_t tot_size = num_possible_cpus() * PMD_SIZE; - - /* on non-NUMA, embedding is better */ - if (!pcpu_need_numa()) - return -EINVAL; + size_t tot_size = nr_units * unit_size; /* don't consume more than 20% of vmalloc area */ if (tot_size > vm_size / 5) { pr_info("PERCPU: too large chunk size %zuMB for " "large page remap\n", tot_size >> 20); - return -EINVAL; + ret = -EINVAL; + goto out_free; } } - /* need PSE */ - if (!cpu_has_pse) { - pr_warning("PERCPU: lpage allocator requires PSE\n"); - return -EINVAL; - } - - return pcpu_lpage_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE, - reserve - PERCPU_FIRST_CHUNK_RESERVE, - PMD_SIZE, - pcpu_fc_alloc, pcpu_fc_free, pcpul_map); + ret = pcpu_lpage_first_chunk(static_size, PERCPU_FIRST_CHUNK_RESERVE, + dyn_size, unit_size, PMD_SIZE, + unit_map, nr_units, + pcpu_fc_alloc, pcpu_fc_free, pcpul_map); +out_free: + if (ret < 0) + free_bootmem(__pa(unit_map), unit_map_size); + return ret; } #else static ssize_t __init setup_pcpu_lpage(size_t static_size, bool chosen) @@ -299,7 +336,8 @@ void __init setup_per_cpu_areas(void) /* alrighty, percpu areas up and running */ delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; for_each_possible_cpu(cpu) { - per_cpu_offset(cpu) = delta + cpu * pcpu_unit_size; + per_cpu_offset(cpu) = + delta + pcpu_unit_map[cpu] * pcpu_unit_size; per_cpu(this_cpu_off, cpu) = per_cpu_offset(cpu); per_cpu(cpu_number, cpu) = cpu; setup_percpu_segment(cpu); diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 1e0e887..8ce91af 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -62,6 +62,7 @@ extern const int *pcpu_unit_map; typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size); typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size); typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr); +typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to); typedef void (*pcpu_fc_map_fn_t)(void *ptr, size_t size, void *addr); extern size_t __init pcpu_setup_first_chunk( @@ -80,18 +81,37 @@ extern ssize_t __init pcpu_4k_first_chunk( pcpu_fc_populate_pte_fn_t populate_pte_fn); #ifdef CONFIG_NEED_MULTIPLE_NODES +extern int __init pcpu_lpage_build_unit_map( + size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep, size_t *unit_sizep, + size_t lpage_size, int *unit_map, + pcpu_fc_cpu_distance_fn_t cpu_distance_fn); + extern ssize_t __init pcpu_lpage_first_chunk( size_t static_size, size_t reserved_size, - ssize_t dyn_size, size_t lpage_size, + size_t dyn_size, size_t unit_size, + size_t lpage_size, const int *unit_map, + int nr_units, pcpu_fc_alloc_fn_t alloc_fn, pcpu_fc_free_fn_t free_fn, pcpu_fc_map_fn_t map_fn); extern void *pcpu_lpage_remapped(void *kaddr); #else +static inline int pcpu_lpage_build_unit_map( + size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep, size_t *unit_sizep, + size_t lpage_size, int *unit_map, + pcpu_fc_cpu_distance_fn_t cpu_distance_fn) +{ + return -EINVAL; +} + static inline ssize_t __init pcpu_lpage_first_chunk( size_t static_size, size_t reserved_size, - ssize_t dyn_size, size_t lpage_size, + size_t dyn_size, size_t unit_size, + size_t lpage_size, const int *unit_map, + int nr_units, pcpu_fc_alloc_fn_t alloc_fn, pcpu_fc_free_fn_t free_fn, pcpu_fc_map_fn_t map_fn) diff --git a/mm/percpu.c b/mm/percpu.c index 2196fae..b3d0bcf 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -59,6 +59,7 @@ #include <linux/bitmap.h> #include <linux/bootmem.h> #include <linux/list.h> +#include <linux/log2.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/mutex.h> @@ -1594,75 +1595,259 @@ out_free_ar: * Large page remapping first chunk setup helper */ #ifdef CONFIG_NEED_MULTIPLE_NODES + +/** + * pcpu_lpage_build_unit_map - build unit_map for large page remapping + * @static_size: the size of static percpu area in bytes + * @reserved_size: the size of reserved percpu area in bytes + * @dyn_sizep: in/out parameter for dynamic size, -1 for auto + * @unit_sizep: out parameter for unit size + * @unit_map: unit_map to be filled + * @cpu_distance_fn: callback to determine distance between cpus + * + * This function builds cpu -> unit map and determine other parameters + * considering needed percpu size, large page size and distances + * between CPUs in NUMA. + * + * CPUs which are of LOCAL_DISTANCE both ways are grouped together and + * may share units in the same large page. The returned configuration + * is guaranteed to have CPUs on different nodes on different large + * pages and >=75% usage of allocated virtual address space. + * + * RETURNS: + * On success, fills in @unit_map, sets *@dyn_sizep, *@unit_sizep and + * returns the number of units to be allocated. -errno on failure. + */ +int __init pcpu_lpage_build_unit_map(size_t static_size, size_t reserved_size, + ssize_t *dyn_sizep, size_t *unit_sizep, + size_t lpage_size, int *unit_map, + pcpu_fc_cpu_distance_fn_t cpu_distance_fn) +{ + static int group_map[NR_CPUS] __initdata; + static int group_cnt[NR_CPUS] __initdata; + int group_cnt_max = 0; + size_t size_sum, min_unit_size, alloc_size; + int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ + int last_allocs; + unsigned int cpu, tcpu; + int group, unit; + + /* + * Determine min_unit_size, alloc_size and max_upa such that + * alloc_size is multiple of lpage_size and is the smallest + * which can accomodate 4k aligned segments which are equal to + * or larger than min_unit_size. + */ + size_sum = pcpu_calc_fc_sizes(static_size, reserved_size, dyn_sizep); + min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); + + alloc_size = roundup(min_unit_size, lpage_size); + upa = alloc_size / min_unit_size; + while (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) + upa--; + max_upa = upa; + + /* group cpus according to their proximity */ + for_each_possible_cpu(cpu) { + group = 0; + next_group: + for_each_possible_cpu(tcpu) { + if (cpu == tcpu) + break; + if (group_map[tcpu] == group && + (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || + cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { + group++; + goto next_group; + } + } + group_map[cpu] = group; + group_cnt[group]++; + group_cnt_max = max(group_cnt_max, group_cnt[group]); + } + + /* + * Expand unit size until address space usage goes over 75% + * and then as much as possible without using more address + * space. + */ + last_allocs = INT_MAX; + for (upa = max_upa; upa; upa--) { + int allocs = 0, wasted = 0; + + if (alloc_size % upa || ((alloc_size / upa) & ~PAGE_MASK)) + continue; + + for (group = 0; group_cnt[group]; group++) { + int this_allocs = DIV_ROUND_UP(group_cnt[group], upa); + allocs += this_allocs; + wasted += this_allocs * upa - group_cnt[group]; + } + + /* + * Don't accept if wastage is over 25%. The + * greater-than comparison ensures upa==1 always + * passes the following check. + */ + if (wasted > num_possible_cpus() / 3) + continue; + + /* and then don't consume more memory */ + if (allocs > last_allocs) + break; + last_allocs = allocs; + best_upa = upa; + } + *unit_sizep = alloc_size / best_upa; + + /* assign units to cpus accordingly */ + unit = 0; + for (group = 0; group_cnt[group]; group++) { + for_each_possible_cpu(cpu) + if (group_map[cpu] == group) + unit_map[cpu] = unit++; + unit = roundup(unit, best_upa); + } + + return unit; /* unit contains aligned number of units */ +} + struct pcpul_ent { - unsigned int cpu; void *ptr; + void *map_addr; }; static size_t pcpul_size; -static size_t pcpul_unit_size; +static size_t pcpul_lpage_size; +static int pcpul_nr_lpages; static struct pcpul_ent *pcpul_map; -static struct vm_struct pcpul_vm; + +static bool __init pcpul_unit_to_cpu(int unit, const int *unit_map, + unsigned int *cpup) +{ + unsigned int cpu; + + for_each_possible_cpu(cpu) + if (unit_map[cpu] == unit) { + if (cpup) + *cpup = cpu; + return true; + } + + return false; +} + +static void __init pcpul_lpage_dump_cfg(const char *lvl, size_t static_size, + size_t reserved_size, size_t dyn_size, + size_t unit_size, size_t lpage_size, + const int *unit_map, int nr_units) +{ + int width = 1, v = nr_units; + char empty_str[] = "--------"; + int upl, lpl; /* units per lpage, lpage per line */ + unsigned int cpu; + int lpage, unit; + + while (v /= 10) + width++; + empty_str[min_t(int, width, sizeof(empty_str) - 1)] = '\0'; + + upl = max_t(int, lpage_size / unit_size, 1); + lpl = rounddown_pow_of_two(max_t(int, 60 / (upl * (width + 1) + 2), 1)); + + printk("%spcpu-lpage: sta/res/dyn=%zu/%zu/%zu unit=%zu lpage=%zu", lvl, + static_size, reserved_size, dyn_size, unit_size, lpage_size); + + for (lpage = 0, unit = 0; unit < nr_units; unit++) { + if (!(unit % upl)) { + if (!(lpage++ % lpl)) { + printk("\n"); + printk("%spcpu-lpage: ", lvl); + } else + printk("| "); + } + if (pcpul_unit_to_cpu(unit, unit_map, &cpu)) + printk("%0*d ", width, cpu); + else + printk("%s ", empty_str); + } + printk("\n"); +} /** * 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 + * @dyn_size: free size for dynamic allocation in bytes + * @unit_size: unit size in bytes * @lpage_size: the size of a large page + * @unit_map: cpu -> unit mapping + * @nr_units: the number of units * @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. + * This allocator uses large page to build and map the first chunk. + * Unlike other helpers, the caller should always specify @dyn_size + * and @unit_size. These parameters along with @unit_map and + * @nr_units can be determined using pcpu_lpage_build_unit_map(). + * This two stage initialization is to allow arch code to evaluate the + * parameters before committing to it. + * + * Large pages are allocated as directed by @unit_map and other + * parameters and mapped to vmalloc space. Unused holes are returned + * to the page allocator. Note that these holes end up being actively + * mapped twice - once to the physical mapping and to the vmalloc area + * for the first percpu chunk. Depending on architecture, this might + * cause problem when changing page attributes of the returned area. + * These double mapped areas can be detected using + * pcpu_lpage_remapped(). * * 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, + size_t dyn_size, size_t unit_size, + size_t lpage_size, const int *unit_map, + int nr_units, 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; + static struct vm_struct vm; + size_t chunk_size = unit_size * nr_units; size_t map_size; unsigned int cpu; - int i, j; ssize_t ret; + int i, j, unit; - /* - * 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_lpage_dump_cfg(KERN_DEBUG, static_size, reserved_size, dyn_size, + unit_size, lpage_size, unit_map, nr_units); - 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; - } + BUG_ON(chunk_size % lpage_size); + + pcpul_size = static_size + reserved_size + dyn_size; + pcpul_lpage_size = lpage_size; + pcpul_nr_lpages = chunk_size / lpage_size; /* allocate pointer array and alloc large pages */ - map_size = PFN_ALIGN(num_possible_cpus() * sizeof(pcpul_map[0])); + map_size = pcpul_nr_lpages * sizeof(pcpul_map[0]); pcpul_map = alloc_bootmem(map_size); - for_each_possible_cpu(cpu) { + /* allocate all pages */ + for (i = 0; i < pcpul_nr_lpages; i++) { + size_t offset = i * lpage_size; + int first_unit = offset / unit_size; + int last_unit = (offset + lpage_size - 1) / unit_size; void *ptr; + /* find out which cpu is mapped to this unit */ + for (unit = first_unit; unit <= last_unit; unit++) + if (pcpul_unit_to_cpu(unit, unit_map, &cpu)) + goto found; + continue; + found: ptr = alloc_fn(cpu, lpage_size); if (!ptr) { pr_warning("PERCPU: failed to allocate large page " @@ -1670,53 +1855,79 @@ ssize_t __init pcpu_lpage_first_chunk(size_t static_size, size_t reserved_size, 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; + pcpul_map[i].ptr = ptr; + } - memcpy(ptr, __per_cpu_load, static_size); + /* return unused holes */ + for (unit = 0; unit < nr_units; unit++) { + size_t start = unit * unit_size; + size_t end = start + unit_size; + size_t off, next; + + /* don't free used part of occupied unit */ + if (pcpul_unit_to_cpu(unit, unit_map, NULL)) + start += pcpul_size; + + /* unit can span more than one page, punch the holes */ + for (off = start; off < end; off = next) { + void *ptr = pcpul_map[off / lpage_size].ptr; + next = min(roundup(off + 1, lpage_size), end); + if (ptr) + free_fn(ptr + off % lpage_size, next - off); + } } - /* 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); + /* allocate address, map and copy */ + vm.flags = VM_ALLOC; + vm.size = chunk_size; + vm_area_register_early(&vm, unit_size); + + for (i = 0; i < pcpul_nr_lpages; i++) { + if (!pcpul_map[i].ptr) + continue; + pcpul_map[i].map_addr = vm.addr + i * lpage_size; + map_fn(pcpul_map[i].ptr, lpage_size, pcpul_map[i].map_addr); + } for_each_possible_cpu(cpu) - map_fn(pcpul_map[cpu].ptr, pcpul_unit_size, - pcpul_vm.addr + cpu * pcpul_unit_size); + memcpy(vm.addr + unit_map[cpu] * unit_size, __per_cpu_load, + static_size); /* we're ready, commit */ pr_info("PERCPU: Remapped at %p with large pages, static data " - "%zu bytes\n", pcpul_vm.addr, static_size); + "%zu bytes\n", vm.addr, static_size); ret = pcpu_setup_first_chunk(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; - } + unit_size, vm.addr, unit_map); + + /* + * Sort pcpul_map array for pcpu_lpage_remapped(). Unmapped + * lpages are pushed to the end and trimmed. + */ + for (i = 0; i < pcpul_nr_lpages - 1; i++) + for (j = i + 1; j < pcpul_nr_lpages; j++) { + struct pcpul_ent tmp; + + if (!pcpul_map[j].ptr) + continue; + if (pcpul_map[i].ptr && + pcpul_map[i].ptr < pcpul_map[j].ptr) + continue; + + tmp = pcpul_map[i]; + pcpul_map[i] = pcpul_map[j]; + pcpul_map[j] = tmp; + } + + while (pcpul_nr_lpages && !pcpul_map[pcpul_nr_lpages - 1].ptr) + pcpul_nr_lpages--; return ret; enomem: - for_each_possible_cpu(cpu) - if (pcpul_map[cpu].ptr) - free_fn(pcpul_map[cpu].ptr, pcpul_size); + for (i = 0; i < pcpul_nr_lpages; i++) + if (pcpul_map[i].ptr) + free_fn(pcpul_map[i].ptr, lpage_size); free_bootmem(__pa(pcpul_map), map_size); return -ENOMEM; } @@ -1739,10 +1950,10 @@ enomem: */ 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; + unsigned long lpage_mask = pcpul_lpage_size - 1; + void *lpage_addr = (void *)((unsigned long)kaddr & ~lpage_mask); + unsigned long offset = (unsigned long)kaddr & lpage_mask; + int left = 0, right = pcpul_nr_lpages - 1; int pos; /* pcpul in use at all? */ @@ -1757,13 +1968,8 @@ void *pcpu_lpage_remapped(void *kaddr) 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; - } + else + return pcpul_map[pos].map_addr + offset; } return NULL; |
