diff options
Diffstat (limited to 'mm/percpu.c')
| -rw-r--r-- | mm/percpu.c | 401 |
1 files changed, 233 insertions, 168 deletions
diff --git a/mm/percpu.c b/mm/percpu.c index c76ef3891e0d..6fc9015534f8 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -76,6 +76,7 @@ #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ +#ifdef CONFIG_SMP /* default addr <-> pcpu_ptr mapping, override in asm/percpu.h if necessary */ #ifndef __addr_to_pcpu_ptr #define __addr_to_pcpu_ptr(addr) \ @@ -89,6 +90,11 @@ (unsigned long)pcpu_base_addr - \ (unsigned long)__per_cpu_start) #endif +#else /* CONFIG_SMP */ +/* on UP, it's always identity mapped */ +#define __addr_to_pcpu_ptr(addr) (void __percpu *)(addr) +#define __pcpu_ptr_to_addr(ptr) (void __force *)(ptr) +#endif /* CONFIG_SMP */ struct pcpu_chunk { struct list_head list; /* linked to pcpu_slot lists */ @@ -820,8 +826,8 @@ fail_unlock_mutex: * @size: size of area to allocate in bytes * @align: alignment of area (max PAGE_SIZE) * - * Allocate percpu area of @size bytes aligned at @align. Might - * sleep. Might trigger writeouts. + * Allocate zero-filled percpu area of @size bytes aligned at @align. + * Might sleep. Might trigger writeouts. * * CONTEXT: * Does GFP_KERNEL allocation. @@ -840,9 +846,10 @@ EXPORT_SYMBOL_GPL(__alloc_percpu); * @size: size of area to allocate in bytes * @align: alignment of area (max PAGE_SIZE) * - * Allocate percpu area of @size bytes aligned at @align from reserved - * percpu area if arch has set it up; otherwise, allocation is served - * from the same dynamic area. Might sleep. Might trigger writeouts. + * Allocate zero-filled percpu area of @size bytes aligned at @align + * from reserved percpu area if arch has set it up; otherwise, + * allocation is served from the same dynamic area. Might sleep. + * Might trigger writeouts. * * CONTEXT: * Does GFP_KERNEL allocation. @@ -949,6 +956,7 @@ EXPORT_SYMBOL_GPL(free_percpu); */ bool is_kernel_percpu_address(unsigned long addr) { +#ifdef CONFIG_SMP const size_t static_size = __per_cpu_end - __per_cpu_start; void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); unsigned int cpu; @@ -959,6 +967,8 @@ bool is_kernel_percpu_address(unsigned long addr) if ((void *)addr >= start && (void *)addr < start + static_size) return true; } +#endif + /* on UP, can't distinguish from other static vars, always false */ return false; } @@ -1067,161 +1077,6 @@ void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai) } /** - * pcpu_build_alloc_info - build alloc_info considering distances between CPUs - * @reserved_size: the size of reserved percpu area in bytes - * @dyn_size: minimum free size for dynamic allocation in bytes - * @atom_size: allocation atom size - * @cpu_distance_fn: callback to determine distance between cpus, optional - * - * This function determines grouping of units, their mappings to cpus - * and other parameters considering needed percpu size, allocation - * atom size and distances between CPUs. - * - * Groups are always mutliples of atom size and CPUs which are of - * LOCAL_DISTANCE both ways are grouped together and share space for - * units in the same group. The returned configuration is guaranteed - * to have CPUs on different nodes on different groups and >=75% usage - * of allocated virtual address space. - * - * RETURNS: - * On success, pointer to the new allocation_info is returned. On - * failure, ERR_PTR value is returned. - */ -static struct pcpu_alloc_info * __init pcpu_build_alloc_info( - size_t reserved_size, size_t dyn_size, - size_t atom_size, - pcpu_fc_cpu_distance_fn_t cpu_distance_fn) -{ - static int group_map[NR_CPUS] __initdata; - static int group_cnt[NR_CPUS] __initdata; - const size_t static_size = __per_cpu_end - __per_cpu_start; - int nr_groups = 1, nr_units = 0; - size_t size_sum, min_unit_size, alloc_size; - int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ - int last_allocs, group, unit; - unsigned int cpu, tcpu; - struct pcpu_alloc_info *ai; - unsigned int *cpu_map; - - /* this function may be called multiple times */ - memset(group_map, 0, sizeof(group_map)); - memset(group_cnt, 0, sizeof(group_cnt)); - - /* calculate size_sum and ensure dyn_size is enough for early alloc */ - size_sum = PFN_ALIGN(static_size + reserved_size + - max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE)); - dyn_size = size_sum - static_size - reserved_size; - - /* - * Determine min_unit_size, alloc_size and max_upa such that - * alloc_size is multiple of atom_size and is the smallest - * which can accomodate 4k aligned segments which are equal to - * or larger than min_unit_size. - */ - min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); - - alloc_size = roundup(min_unit_size, atom_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_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || - cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { - group++; - nr_groups = max(nr_groups, group + 1); - goto next_group; - } - } - group_map[cpu] = group; - 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 < nr_groups; 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 1/3. 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; - } - upa = best_upa; - - /* allocate and fill alloc_info */ - for (group = 0; group < nr_groups; group++) - nr_units += roundup(group_cnt[group], upa); - - ai = pcpu_alloc_alloc_info(nr_groups, nr_units); - if (!ai) - return ERR_PTR(-ENOMEM); - cpu_map = ai->groups[0].cpu_map; - - for (group = 0; group < nr_groups; group++) { - ai->groups[group].cpu_map = cpu_map; - cpu_map += roundup(group_cnt[group], upa); - } - - ai->static_size = static_size; - ai->reserved_size = reserved_size; - ai->dyn_size = dyn_size; - ai->unit_size = alloc_size / upa; - ai->atom_size = atom_size; - ai->alloc_size = alloc_size; - - for (group = 0, unit = 0; group_cnt[group]; group++) { - struct pcpu_group_info *gi = &ai->groups[group]; - - /* - * Initialize base_offset as if all groups are located - * back-to-back. The caller should update this to - * reflect actual allocation. - */ - gi->base_offset = unit * ai->unit_size; - - for_each_possible_cpu(cpu) - if (group_map[cpu] == group) - gi->cpu_map[gi->nr_units++] = cpu; - gi->nr_units = roundup(gi->nr_units, upa); - unit += gi->nr_units; - } - BUG_ON(unit != nr_units); - - return ai; -} - -/** * pcpu_dump_alloc_info - print out information about pcpu_alloc_info * @lvl: loglevel * @ai: allocation info to dump @@ -1363,7 +1218,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, /* sanity checks */ PCPU_SETUP_BUG_ON(ai->nr_groups <= 0); +#ifdef CONFIG_SMP PCPU_SETUP_BUG_ON(!ai->static_size); +#endif PCPU_SETUP_BUG_ON(!base_addr); PCPU_SETUP_BUG_ON(ai->unit_size < size_sum); PCPU_SETUP_BUG_ON(ai->unit_size & ~PAGE_MASK); @@ -1488,6 +1345,8 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, return 0; } +#ifdef CONFIG_SMP + const char *pcpu_fc_names[PCPU_FC_NR] __initdata = { [PCPU_FC_AUTO] = "auto", [PCPU_FC_EMBED] = "embed", @@ -1515,8 +1374,180 @@ static int __init percpu_alloc_setup(char *str) } early_param("percpu_alloc", percpu_alloc_setup); +/* + * pcpu_embed_first_chunk() is used by the generic percpu setup. + * Build it if needed by the arch config or the generic setup is going + * to be used. + */ #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \ !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) +#define BUILD_EMBED_FIRST_CHUNK +#endif + +/* build pcpu_page_first_chunk() iff needed by the arch config */ +#if defined(CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK) +#define BUILD_PAGE_FIRST_CHUNK +#endif + +/* pcpu_build_alloc_info() is used by both embed and page first chunk */ +#if defined(BUILD_EMBED_FIRST_CHUNK) || defined(BUILD_PAGE_FIRST_CHUNK) +/** + * pcpu_build_alloc_info - build alloc_info considering distances between CPUs + * @reserved_size: the size of reserved percpu area in bytes + * @dyn_size: minimum free size for dynamic allocation in bytes + * @atom_size: allocation atom size + * @cpu_distance_fn: callback to determine distance between cpus, optional + * + * This function determines grouping of units, their mappings to cpus + * and other parameters considering needed percpu size, allocation + * atom size and distances between CPUs. + * + * Groups are always mutliples of atom size and CPUs which are of + * LOCAL_DISTANCE both ways are grouped together and share space for + * units in the same group. The returned configuration is guaranteed + * to have CPUs on different nodes on different groups and >=75% usage + * of allocated virtual address space. + * + * RETURNS: + * On success, pointer to the new allocation_info is returned. On + * failure, ERR_PTR value is returned. + */ +static struct pcpu_alloc_info * __init pcpu_build_alloc_info( + size_t reserved_size, size_t dyn_size, + size_t atom_size, + pcpu_fc_cpu_distance_fn_t cpu_distance_fn) +{ + static int group_map[NR_CPUS] __initdata; + static int group_cnt[NR_CPUS] __initdata; + const size_t static_size = __per_cpu_end - __per_cpu_start; + int nr_groups = 1, nr_units = 0; + size_t size_sum, min_unit_size, alloc_size; + int upa, max_upa, uninitialized_var(best_upa); /* units_per_alloc */ + int last_allocs, group, unit; + unsigned int cpu, tcpu; + struct pcpu_alloc_info *ai; + unsigned int *cpu_map; + + /* this function may be called multiple times */ + memset(group_map, 0, sizeof(group_map)); + memset(group_cnt, 0, sizeof(group_cnt)); + + /* calculate size_sum and ensure dyn_size is enough for early alloc */ + size_sum = PFN_ALIGN(static_size + reserved_size + + max_t(size_t, dyn_size, PERCPU_DYNAMIC_EARLY_SIZE)); + dyn_size = size_sum - static_size - reserved_size; + + /* + * Determine min_unit_size, alloc_size and max_upa such that + * alloc_size is multiple of atom_size and is the smallest + * which can accomodate 4k aligned segments which are equal to + * or larger than min_unit_size. + */ + min_unit_size = max_t(size_t, size_sum, PCPU_MIN_UNIT_SIZE); + + alloc_size = roundup(min_unit_size, atom_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_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || + cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { + group++; + nr_groups = max(nr_groups, group + 1); + goto next_group; + } + } + group_map[cpu] = group; + 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 < nr_groups; 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 1/3. 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; + } + upa = best_upa; + + /* allocate and fill alloc_info */ + for (group = 0; group < nr_groups; group++) + nr_units += roundup(group_cnt[group], upa); + + ai = pcpu_alloc_alloc_info(nr_groups, nr_units); + if (!ai) + return ERR_PTR(-ENOMEM); + cpu_map = ai->groups[0].cpu_map; + + for (group = 0; group < nr_groups; group++) { + ai->groups[group].cpu_map = cpu_map; + cpu_map += roundup(group_cnt[group], upa); + } + + ai->static_size = static_size; + ai->reserved_size = reserved_size; + ai->dyn_size = dyn_size; + ai->unit_size = alloc_size / upa; + ai->atom_size = atom_size; + ai->alloc_size = alloc_size; + + for (group = 0, unit = 0; group_cnt[group]; group++) { + struct pcpu_group_info *gi = &ai->groups[group]; + + /* + * Initialize base_offset as if all groups are located + * back-to-back. The caller should update this to + * reflect actual allocation. + */ + gi->base_offset = unit * ai->unit_size; + + for_each_possible_cpu(cpu) + if (group_map[cpu] == group) + gi->cpu_map[gi->nr_units++] = cpu; + gi->nr_units = roundup(gi->nr_units, upa); + unit += gi->nr_units; + } + BUG_ON(unit != nr_units); + + return ai; +} +#endif /* BUILD_EMBED_FIRST_CHUNK || BUILD_PAGE_FIRST_CHUNK */ + +#if defined(BUILD_EMBED_FIRST_CHUNK) /** * pcpu_embed_first_chunk - embed the first percpu chunk into bootmem * @reserved_size: the size of reserved percpu area in bytes @@ -1645,10 +1676,9 @@ out_free: free_bootmem(__pa(areas), areas_size); return rc; } -#endif /* CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK || - !CONFIG_HAVE_SETUP_PER_CPU_AREA */ +#endif /* BUILD_EMBED_FIRST_CHUNK */ -#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK +#ifdef BUILD_PAGE_FIRST_CHUNK /** * pcpu_page_first_chunk - map the first chunk using PAGE_SIZE pages * @reserved_size: the size of reserved percpu area in bytes @@ -1756,10 +1786,11 @@ out_free_ar: pcpu_free_alloc_info(ai); return rc; } -#endif /* CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK */ +#endif /* BUILD_PAGE_FIRST_CHUNK */ +#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA /* - * Generic percpu area setup. + * Generic SMP percpu area setup. * * The embedding helper is used because its behavior closely resembles * the original non-dynamic generic percpu area setup. This is @@ -1770,7 +1801,6 @@ out_free_ar: * on the physical linear memory mapping which uses large page * mappings on applicable archs. */ -#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; EXPORT_SYMBOL(__per_cpu_offset); @@ -1799,13 +1829,48 @@ void __init setup_per_cpu_areas(void) PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, NULL, pcpu_dfl_fc_alloc, pcpu_dfl_fc_free); if (rc < 0) - panic("Failed to initialized percpu areas."); + panic("Failed to initialize percpu areas."); delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; for_each_possible_cpu(cpu) __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu]; } -#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ +#endif /* CONFIG_HAVE_SETUP_PER_CPU_AREA */ + +#else /* CONFIG_SMP */ + +/* + * UP percpu area setup. + * + * UP always uses km-based percpu allocator with identity mapping. + * Static percpu variables are indistinguishable from the usual static + * variables and don't require any special preparation. + */ +void __init setup_per_cpu_areas(void) +{ + const size_t unit_size = + roundup_pow_of_two(max_t(size_t, PCPU_MIN_UNIT_SIZE, + PERCPU_DYNAMIC_RESERVE)); + struct pcpu_alloc_info *ai; + void *fc; + + ai = pcpu_alloc_alloc_info(1, 1); + fc = __alloc_bootmem(unit_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS)); + if (!ai || !fc) + panic("Failed to allocate memory for percpu areas."); + + ai->dyn_size = unit_size; + ai->unit_size = unit_size; + ai->atom_size = unit_size; + ai->alloc_size = unit_size; + ai->groups[0].nr_units = 1; + ai->groups[0].cpu_map[0] = 0; + + if (pcpu_setup_first_chunk(ai, fc) < 0) + panic("Failed to initialize percpu areas."); +} + +#endif /* CONFIG_SMP */ /* * First and reserved chunks are initialized with temporary allocation |
