diff options
| -rw-r--r-- | drivers/base/cpu.c | 2 | ||||
| -rw-r--r-- | include/linux/percpu.h | 6 | ||||
| -rw-r--r-- | kernel/sched.c | 22 | ||||
| -rw-r--r-- | mm/percpu.c | 162 |
4 files changed, 132 insertions, 60 deletions
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index e62a4ccea54d..69ee5b7517ec 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -97,7 +97,7 @@ static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute * boot up and this data does not change there after. Hence this * operation should be safe. No locking required. */ - addr = __pa(per_cpu_ptr(crash_notes, cpunum)); + addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum)); rc = sprintf(buf, "%Lx\n", addr); return rc; } diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 522f421ec213..cf5efbcf716c 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -130,6 +130,7 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size, extern void *__alloc_reserved_percpu(size_t size, size_t align); extern void *__alloc_percpu(size_t size, size_t align); extern void free_percpu(void *__pdata); +extern phys_addr_t per_cpu_ptr_to_phys(void *addr); #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA extern void __init setup_per_cpu_areas(void); @@ -155,6 +156,11 @@ static inline void free_percpu(void *p) kfree(p); } +static inline phys_addr_t per_cpu_ptr_to_phys(void *addr) +{ + return __pa(addr); +} + static inline void __init setup_per_cpu_areas(void) { } static inline void *pcpu_lpage_remapped(void *kaddr) diff --git a/kernel/sched.c b/kernel/sched.c index 854ab418fd42..eecf070ffd1a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1563,11 +1563,7 @@ static unsigned long cpu_avg_load_per_task(int cpu) #ifdef CONFIG_FAIR_GROUP_SCHED -struct update_shares_data { - unsigned long rq_weight[NR_CPUS]; -}; - -static DEFINE_PER_CPU(struct update_shares_data, update_shares_data); +static __read_mostly unsigned long *update_shares_data; static void __set_se_shares(struct sched_entity *se, unsigned long shares); @@ -1577,12 +1573,12 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares); static void update_group_shares_cpu(struct task_group *tg, int cpu, unsigned long sd_shares, unsigned long sd_rq_weight, - struct update_shares_data *usd) + unsigned long *usd_rq_weight) { unsigned long shares, rq_weight; int boost = 0; - rq_weight = usd->rq_weight[cpu]; + rq_weight = usd_rq_weight[cpu]; if (!rq_weight) { boost = 1; rq_weight = NICE_0_LOAD; @@ -1617,7 +1613,7 @@ static void update_group_shares_cpu(struct task_group *tg, int cpu, static int tg_shares_up(struct task_group *tg, void *data) { unsigned long weight, rq_weight = 0, shares = 0; - struct update_shares_data *usd; + unsigned long *usd_rq_weight; struct sched_domain *sd = data; unsigned long flags; int i; @@ -1626,11 +1622,11 @@ static int tg_shares_up(struct task_group *tg, void *data) return 0; local_irq_save(flags); - usd = &__get_cpu_var(update_shares_data); + usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id()); for_each_cpu(i, sched_domain_span(sd)) { weight = tg->cfs_rq[i]->load.weight; - usd->rq_weight[i] = weight; + usd_rq_weight[i] = weight; /* * If there are currently no tasks on the cpu pretend there @@ -1651,7 +1647,7 @@ static int tg_shares_up(struct task_group *tg, void *data) shares = tg->shares; for_each_cpu(i, sched_domain_span(sd)) - update_group_shares_cpu(tg, i, shares, rq_weight, usd); + update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight); local_irq_restore(flags); @@ -9406,6 +9402,10 @@ void __init sched_init(void) #endif /* CONFIG_USER_SCHED */ #endif /* CONFIG_GROUP_SCHED */ +#if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP + update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long), + __alignof__(unsigned long)); +#endif for_each_possible_cpu(i) { struct rq *rq; diff --git a/mm/percpu.c b/mm/percpu.c index e2e80fc78601..442010cc91c6 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -72,6 +72,7 @@ #include <asm/cacheflush.h> #include <asm/sections.h> #include <asm/tlbflush.h> +#include <asm/io.h> #define PCPU_SLOT_BASE_SHIFT 5 /* 1-31 shares the same slot */ #define PCPU_DFL_MAP_ALLOC 16 /* start a map with 16 ents */ @@ -151,7 +152,10 @@ static int pcpu_reserved_chunk_limit; * * During allocation, pcpu_alloc_mutex is kept locked all the time and * pcpu_lock is grabbed and released as necessary. All actual memory - * allocations are done using GFP_KERNEL with pcpu_lock released. + * allocations are done using GFP_KERNEL with pcpu_lock released. In + * general, percpu memory can't be allocated with irq off but + * irqsave/restore are still used in alloc path so that it can be used + * from early init path - sched_init() specifically. * * Free path accesses and alters only the index data structures, so it * can be safely called from atomic context. When memory needs to be @@ -350,63 +354,86 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr) } /** - * pcpu_extend_area_map - extend area map for allocation - * @chunk: target chunk + * pcpu_need_to_extend - determine whether chunk area map needs to be extended + * @chunk: chunk of interest * - * Extend area map of @chunk so that it can accomodate an allocation. - * A single allocation can split an area into three areas, so this - * function makes sure that @chunk->map has at least two extra slots. + * Determine whether area map of @chunk needs to be extended to + * accomodate a new allocation. * * CONTEXT: - * pcpu_alloc_mutex, pcpu_lock. pcpu_lock is released and reacquired - * if area map is extended. + * pcpu_lock. * * RETURNS: - * 0 if noop, 1 if successfully extended, -errno on failure. + * New target map allocation length if extension is necessary, 0 + * otherwise. */ -static int pcpu_extend_area_map(struct pcpu_chunk *chunk) - __releases(lock) __acquires(lock) +static int pcpu_need_to_extend(struct pcpu_chunk *chunk) { int new_alloc; - int *new; - size_t size; - /* has enough? */ if (chunk->map_alloc >= chunk->map_used + 2) return 0; - spin_unlock_irq(&pcpu_lock); - new_alloc = PCPU_DFL_MAP_ALLOC; while (new_alloc < chunk->map_used + 2) new_alloc *= 2; - new = pcpu_mem_alloc(new_alloc * sizeof(new[0])); - if (!new) { - spin_lock_irq(&pcpu_lock); + return new_alloc; +} + +/** + * pcpu_extend_area_map - extend area map of a chunk + * @chunk: chunk of interest + * @new_alloc: new target allocation length of the area map + * + * Extend area map of @chunk to have @new_alloc entries. + * + * CONTEXT: + * Does GFP_KERNEL allocation. Grabs and releases pcpu_lock. + * + * RETURNS: + * 0 on success, -errno on failure. + */ +static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc) +{ + int *old = NULL, *new = NULL; + size_t old_size = 0, new_size = new_alloc * sizeof(new[0]); + unsigned long flags; + + new = pcpu_mem_alloc(new_size); + if (!new) return -ENOMEM; - } - /* - * Acquire pcpu_lock and switch to new area map. Only free - * could have happened inbetween, so map_used couldn't have - * grown. - */ - spin_lock_irq(&pcpu_lock); - BUG_ON(new_alloc < chunk->map_used + 2); + /* acquire pcpu_lock and switch to new area map */ + spin_lock_irqsave(&pcpu_lock, flags); - size = chunk->map_alloc * sizeof(chunk->map[0]); - memcpy(new, chunk->map, size); + if (new_alloc <= chunk->map_alloc) + goto out_unlock; + + old_size = chunk->map_alloc * sizeof(chunk->map[0]); + memcpy(new, chunk->map, old_size); /* * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is * one of the first chunks and still using static map. */ if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC) - pcpu_mem_free(chunk->map, size); + old = chunk->map; chunk->map_alloc = new_alloc; chunk->map = new; + new = NULL; + +out_unlock: + spin_unlock_irqrestore(&pcpu_lock, flags); + + /* + * pcpu_mem_free() might end up calling vfree() which uses + * IRQ-unsafe lock and thus can't be called under pcpu_lock. + */ + pcpu_mem_free(old, old_size); + pcpu_mem_free(new, new_size); + return 0; } @@ -1045,7 +1072,8 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved) static int warn_limit = 10; struct pcpu_chunk *chunk; const char *err; - int slot, off; + int slot, off, new_alloc; + unsigned long flags; if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { WARN(true, "illegal size (%zu) or align (%zu) for " @@ -1054,19 +1082,30 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved) } mutex_lock(&pcpu_alloc_mutex); - spin_lock_irq(&pcpu_lock); + spin_lock_irqsave(&pcpu_lock, flags); /* serve reserved allocations from the reserved chunk if available */ if (reserved && pcpu_reserved_chunk) { chunk = pcpu_reserved_chunk; - if (size > chunk->contig_hint || - pcpu_extend_area_map(chunk) < 0) { - err = "failed to extend area map of reserved chunk"; + + if (size > chunk->contig_hint) { + err = "alloc from reserved chunk failed"; goto fail_unlock; } + + while ((new_alloc = pcpu_need_to_extend(chunk))) { + spin_unlock_irqrestore(&pcpu_lock, flags); + if (pcpu_extend_area_map(chunk, new_alloc) < 0) { + err = "failed to extend area map of reserved chunk"; + goto fail_unlock_mutex; + } + spin_lock_irqsave(&pcpu_lock, flags); + } + off = pcpu_alloc_area(chunk, size, align); if (off >= 0) goto area_found; + err = "alloc from reserved chunk failed"; goto fail_unlock; } @@ -1078,14 +1117,20 @@ restart: if (size > chunk->contig_hint) continue; - switch (pcpu_extend_area_map(chunk)) { - case 0: - break; - case 1: - goto restart; /* pcpu_lock dropped, restart */ - default: - err = "failed to extend area map"; - goto fail_unlock; + new_alloc = pcpu_need_to_extend(chunk); + if (new_alloc) { + spin_unlock_irqrestore(&pcpu_lock, flags); + if (pcpu_extend_area_map(chunk, + new_alloc) < 0) { + err = "failed to extend area map"; + goto fail_unlock_mutex; + } + spin_lock_irqsave(&pcpu_lock, flags); + /* + * pcpu_lock has been dropped, need to + * restart cpu_slot list walking. + */ + goto restart; } off = pcpu_alloc_area(chunk, size, align); @@ -1095,7 +1140,7 @@ restart: } /* hmmm... no space left, create a new chunk */ - spin_unlock_irq(&pcpu_lock); + spin_unlock_irqrestore(&pcpu_lock, flags); chunk = alloc_pcpu_chunk(); if (!chunk) { @@ -1103,16 +1148,16 @@ restart: goto fail_unlock_mutex; } - spin_lock_irq(&pcpu_lock); + spin_lock_irqsave(&pcpu_lock, flags); pcpu_chunk_relocate(chunk, -1); goto restart; area_found: - spin_unlock_irq(&pcpu_lock); + spin_unlock_irqrestore(&pcpu_lock, flags); /* populate, map and clear the area */ if (pcpu_populate_chunk(chunk, off, size)) { - spin_lock_irq(&pcpu_lock); + spin_lock_irqsave(&pcpu_lock, flags); pcpu_free_area(chunk, off); err = "failed to populate"; goto fail_unlock; @@ -1124,7 +1169,7 @@ area_found: return __addr_to_pcpu_ptr(chunk->base_addr + off); fail_unlock: - spin_unlock_irq(&pcpu_lock); + spin_unlock_irqrestore(&pcpu_lock, flags); fail_unlock_mutex: mutex_unlock(&pcpu_alloc_mutex); if (warn_limit) { @@ -1256,6 +1301,27 @@ void free_percpu(void *ptr) } EXPORT_SYMBOL_GPL(free_percpu); +/** + * per_cpu_ptr_to_phys - convert translated percpu address to physical address + * @addr: the address to be converted to physical address + * + * Given @addr which is dereferenceable address obtained via one of + * percpu access macros, this function translates it into its physical + * address. The caller is responsible for ensuring @addr stays valid + * until this function finishes. + * + * RETURNS: + * The physical address for @addr. + */ +phys_addr_t per_cpu_ptr_to_phys(void *addr) +{ + if ((unsigned long)addr < VMALLOC_START || + (unsigned long)addr >= VMALLOC_END) + return __pa(addr); + else + return page_to_phys(vmalloc_to_page(addr)); +} + static inline size_t pcpu_calc_fc_sizes(size_t static_size, size_t reserved_size, ssize_t *dyn_sizep) |