diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Makefile | 6 | ||||
| -rw-r--r-- | mm/memory.c | 249 | ||||
| -rw-r--r-- | mm/mmu_gather.c | 261 |
3 files changed, 264 insertions, 252 deletions
diff --git a/mm/Makefile b/mm/Makefile index 8716bdabe1e6..7c48e0d3d8ab 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -23,9 +23,9 @@ KCOV_INSTRUMENT_vmstat.o := n mmu-y := nommu.o mmu-$(CONFIG_MMU) := gup.o highmem.o memory.o mincore.o \ - mlock.o mmap.o mprotect.o mremap.o msync.o \ - page_vma_mapped.o pagewalk.o pgtable-generic.o \ - rmap.o vmalloc.o + mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \ + msync.o page_vma_mapped.o pagewalk.o \ + pgtable-generic.o rmap.o vmalloc.o ifdef CONFIG_CROSS_MEMORY_ATTACH diff --git a/mm/memory.c b/mm/memory.c index 9135f48e8d84..21a5e6e4758b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -186,255 +186,6 @@ static void check_sync_rss_stat(struct task_struct *task) #endif /* SPLIT_RSS_COUNTING */ -#ifdef HAVE_GENERIC_MMU_GATHER - -static bool tlb_next_batch(struct mmu_gather *tlb) -{ - struct mmu_gather_batch *batch; - - batch = tlb->active; - if (batch->next) { - tlb->active = batch->next; - return true; - } - - if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) - return false; - - batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); - if (!batch) - return false; - - tlb->batch_count++; - batch->next = NULL; - batch->nr = 0; - batch->max = MAX_GATHER_BATCH; - - tlb->active->next = batch; - tlb->active = batch; - - return true; -} - -void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, - unsigned long start, unsigned long end) -{ - tlb->mm = mm; - - /* Is it from 0 to ~0? */ - tlb->fullmm = !(start | (end+1)); - tlb->need_flush_all = 0; - tlb->local.next = NULL; - tlb->local.nr = 0; - tlb->local.max = ARRAY_SIZE(tlb->__pages); - tlb->active = &tlb->local; - tlb->batch_count = 0; - -#ifdef CONFIG_HAVE_RCU_TABLE_FREE - tlb->batch = NULL; -#endif - tlb->page_size = 0; - - __tlb_reset_range(tlb); -} - -static void tlb_flush_mmu_free(struct mmu_gather *tlb) -{ - struct mmu_gather_batch *batch; - -#ifdef CONFIG_HAVE_RCU_TABLE_FREE - tlb_table_flush(tlb); -#endif - for (batch = &tlb->local; batch && batch->nr; batch = batch->next) { - free_pages_and_swap_cache(batch->pages, batch->nr); - batch->nr = 0; - } - tlb->active = &tlb->local; -} - -void tlb_flush_mmu(struct mmu_gather *tlb) -{ - tlb_flush_mmu_tlbonly(tlb); - tlb_flush_mmu_free(tlb); -} - -/* tlb_finish_mmu - * Called at the end of the shootdown operation to free up any resources - * that were required. - */ -void arch_tlb_finish_mmu(struct mmu_gather *tlb, - unsigned long start, unsigned long end, bool force) -{ - struct mmu_gather_batch *batch, *next; - - if (force) { - __tlb_reset_range(tlb); - __tlb_adjust_range(tlb, start, end - start); - } - - tlb_flush_mmu(tlb); - - /* keep the page table cache within bounds */ - check_pgt_cache(); - - for (batch = tlb->local.next; batch; batch = next) { - next = batch->next; - free_pages((unsigned long)batch, 0); - } - tlb->local.next = NULL; -} - -/* __tlb_remove_page - * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while - * handling the additional races in SMP caused by other CPUs caching valid - * mappings in their TLBs. Returns the number of free page slots left. - * When out of page slots we must call tlb_flush_mmu(). - *returns true if the caller should flush. - */ -bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size) -{ - struct mmu_gather_batch *batch; - - VM_BUG_ON(!tlb->end); - VM_WARN_ON(tlb->page_size != page_size); - - batch = tlb->active; - /* - * Add the page and check if we are full. If so - * force a flush. - */ - batch->pages[batch->nr++] = page; - if (batch->nr == batch->max) { - if (!tlb_next_batch(tlb)) - return true; - batch = tlb->active; - } - VM_BUG_ON_PAGE(batch->nr > batch->max, page); - - return false; -} - -#endif /* HAVE_GENERIC_MMU_GATHER */ - -#ifdef CONFIG_HAVE_RCU_TABLE_FREE - -/* - * See the comment near struct mmu_table_batch. - */ - -/* - * If we want tlb_remove_table() to imply TLB invalidates. - */ -static inline void tlb_table_invalidate(struct mmu_gather *tlb) -{ -#ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE - /* - * Invalidate page-table caches used by hardware walkers. Then we still - * need to RCU-sched wait while freeing the pages because software - * walkers can still be in-flight. - */ - tlb_flush_mmu_tlbonly(tlb); -#endif -} - -static void tlb_remove_table_smp_sync(void *arg) -{ - /* Simply deliver the interrupt */ -} - -static void tlb_remove_table_one(void *table) -{ - /* - * This isn't an RCU grace period and hence the page-tables cannot be - * assumed to be actually RCU-freed. - * - * It is however sufficient for software page-table walkers that rely on - * IRQ disabling. See the comment near struct mmu_table_batch. - */ - smp_call_function(tlb_remove_table_smp_sync, NULL, 1); - __tlb_remove_table(table); -} - -static void tlb_remove_table_rcu(struct rcu_head *head) -{ - struct mmu_table_batch *batch; - int i; - - batch = container_of(head, struct mmu_table_batch, rcu); - - for (i = 0; i < batch->nr; i++) - __tlb_remove_table(batch->tables[i]); - - free_page((unsigned long)batch); -} - -void tlb_table_flush(struct mmu_gather *tlb) -{ - struct mmu_table_batch **batch = &tlb->batch; - - if (*batch) { - tlb_table_invalidate(tlb); - call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); - *batch = NULL; - } -} - -void tlb_remove_table(struct mmu_gather *tlb, void *table) -{ - struct mmu_table_batch **batch = &tlb->batch; - - if (*batch == NULL) { - *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); - if (*batch == NULL) { - tlb_table_invalidate(tlb); - tlb_remove_table_one(table); - return; - } - (*batch)->nr = 0; - } - - (*batch)->tables[(*batch)->nr++] = table; - if ((*batch)->nr == MAX_TABLE_BATCH) - tlb_table_flush(tlb); -} - -#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ - -/** - * tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down - * @tlb: the mmu_gather structure to initialize - * @mm: the mm_struct of the target address space - * @start: start of the region that will be removed from the page-table - * @end: end of the region that will be removed from the page-table - * - * Called to initialize an (on-stack) mmu_gather structure for page-table - * tear-down from @mm. The @start and @end are set to 0 and -1 - * respectively when @mm is without users and we're going to destroy - * the full address space (exit/execve). - */ -void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, - unsigned long start, unsigned long end) -{ - arch_tlb_gather_mmu(tlb, mm, start, end); - inc_tlb_flush_pending(tlb->mm); -} - -void tlb_finish_mmu(struct mmu_gather *tlb, - unsigned long start, unsigned long end) -{ - /* - * If there are parallel threads are doing PTE changes on same range - * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB - * flush by batching, a thread has stable TLB entry can fail to flush - * the TLB by observing pte_none|!pte_dirty, for example so flush TLB - * forcefully if we detect parallel PTE batching threads. - */ - bool force = mm_tlb_flush_nested(tlb->mm); - - arch_tlb_finish_mmu(tlb, start, end, force); - dec_tlb_flush_pending(tlb->mm); -} - /* * Note: this doesn't free the actual pages themselves. That * has been handled earlier when unmapping all the memory regions. diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c new file mode 100644 index 000000000000..2a9fbc4a37d5 --- /dev/null +++ b/mm/mmu_gather.c @@ -0,0 +1,261 @@ +#include <linux/gfp.h> +#include <linux/highmem.h> +#include <linux/kernel.h> +#include <linux/mmdebug.h> +#include <linux/mm_types.h> +#include <linux/pagemap.h> +#include <linux/rcupdate.h> +#include <linux/smp.h> +#include <linux/swap.h> + +#include <asm/pgalloc.h> +#include <asm/tlb.h> + +#ifdef HAVE_GENERIC_MMU_GATHER + +static bool tlb_next_batch(struct mmu_gather *tlb) +{ + struct mmu_gather_batch *batch; + + batch = tlb->active; + if (batch->next) { + tlb->active = batch->next; + return true; + } + + if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) + return false; + + batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); + if (!batch) + return false; + + tlb->batch_count++; + batch->next = NULL; + batch->nr = 0; + batch->max = MAX_GATHER_BATCH; + + tlb->active->next = batch; + tlb->active = batch; + + return true; +} + +void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, + unsigned long start, unsigned long end) +{ + tlb->mm = mm; + + /* Is it from 0 to ~0? */ + tlb->fullmm = !(start | (end+1)); + tlb->need_flush_all = 0; + tlb->local.next = NULL; + tlb->local.nr = 0; + tlb->local.max = ARRAY_SIZE(tlb->__pages); + tlb->active = &tlb->local; + tlb->batch_count = 0; + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + tlb->batch = NULL; +#endif + tlb->page_size = 0; + + __tlb_reset_range(tlb); +} + +void tlb_flush_mmu_free(struct mmu_gather *tlb) +{ + struct mmu_gather_batch *batch; + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + tlb_table_flush(tlb); +#endif + for (batch = &tlb->local; batch && batch->nr; batch = batch->next) { + free_pages_and_swap_cache(batch->pages, batch->nr); + batch->nr = 0; + } + tlb->active = &tlb->local; +} + +void tlb_flush_mmu(struct mmu_gather *tlb) +{ + tlb_flush_mmu_tlbonly(tlb); + tlb_flush_mmu_free(tlb); +} + +/* tlb_finish_mmu + * Called at the end of the shootdown operation to free up any resources + * that were required. + */ +void arch_tlb_finish_mmu(struct mmu_gather *tlb, + unsigned long start, unsigned long end, bool force) +{ + struct mmu_gather_batch *batch, *next; + + if (force) { + __tlb_reset_range(tlb); + __tlb_adjust_range(tlb, start, end - start); + } + + tlb_flush_mmu(tlb); + + /* keep the page table cache within bounds */ + check_pgt_cache(); + + for (batch = tlb->local.next; batch; batch = next) { + next = batch->next; + free_pages((unsigned long)batch, 0); + } + tlb->local.next = NULL; +} + +/* __tlb_remove_page + * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while + * handling the additional races in SMP caused by other CPUs caching valid + * mappings in their TLBs. Returns the number of free page slots left. + * When out of page slots we must call tlb_flush_mmu(). + *returns true if the caller should flush. + */ +bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size) +{ + struct mmu_gather_batch *batch; + + VM_BUG_ON(!tlb->end); + VM_WARN_ON(tlb->page_size != page_size); + + batch = tlb->active; + /* + * Add the page and check if we are full. If so + * force a flush. + */ + batch->pages[batch->nr++] = page; + if (batch->nr == batch->max) { + if (!tlb_next_batch(tlb)) + return true; + batch = tlb->active; + } + VM_BUG_ON_PAGE(batch->nr > batch->max, page); + + return false; +} + +#endif /* HAVE_GENERIC_MMU_GATHER */ + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + +/* + * See the comment near struct mmu_table_batch. + */ + +/* + * If we want tlb_remove_table() to imply TLB invalidates. + */ +static inline void tlb_table_invalidate(struct mmu_gather *tlb) +{ +#ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE + /* + * Invalidate page-table caches used by hardware walkers. Then we still + * need to RCU-sched wait while freeing the pages because software + * walkers can still be in-flight. + */ + tlb_flush_mmu_tlbonly(tlb); +#endif +} + +static void tlb_remove_table_smp_sync(void *arg) +{ + /* Simply deliver the interrupt */ +} + +static void tlb_remove_table_one(void *table) +{ + /* + * This isn't an RCU grace period and hence the page-tables cannot be + * assumed to be actually RCU-freed. + * + * It is however sufficient for software page-table walkers that rely on + * IRQ disabling. See the comment near struct mmu_table_batch. + */ + smp_call_function(tlb_remove_table_smp_sync, NULL, 1); + __tlb_remove_table(table); +} + +static void tlb_remove_table_rcu(struct rcu_head *head) +{ + struct mmu_table_batch *batch; + int i; + + batch = container_of(head, struct mmu_table_batch, rcu); + + for (i = 0; i < batch->nr; i++) + __tlb_remove_table(batch->tables[i]); + + free_page((unsigned long)batch); +} + +void tlb_table_flush(struct mmu_gather *tlb) +{ + struct mmu_table_batch **batch = &tlb->batch; + + if (*batch) { + tlb_table_invalidate(tlb); + call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); + *batch = NULL; + } +} + +void tlb_remove_table(struct mmu_gather *tlb, void *table) +{ + struct mmu_table_batch **batch = &tlb->batch; + + if (*batch == NULL) { + *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); + if (*batch == NULL) { + tlb_table_invalidate(tlb); + tlb_remove_table_one(table); + return; + } + (*batch)->nr = 0; + } + + (*batch)->tables[(*batch)->nr++] = table; + if ((*batch)->nr == MAX_TABLE_BATCH) + tlb_table_flush(tlb); +} + +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ + +/** + * tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down + * @tlb: the mmu_gather structure to initialize + * @mm: the mm_struct of the target address space + * @start: start of the region that will be removed from the page-table + * @end: end of the region that will be removed from the page-table + * + * Called to initialize an (on-stack) mmu_gather structure for page-table + * tear-down from @mm. The @start and @end are set to 0 and -1 + * respectively when @mm is without users and we're going to destroy + * the full address space (exit/execve). + */ +void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, + unsigned long start, unsigned long end) +{ + arch_tlb_gather_mmu(tlb, mm, start, end); + inc_tlb_flush_pending(tlb->mm); +} + +void tlb_finish_mmu(struct mmu_gather *tlb, + unsigned long start, unsigned long end) +{ + /* + * If there are parallel threads are doing PTE changes on same range + * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB + * flush by batching, a thread has stable TLB entry can fail to flush + * the TLB by observing pte_none|!pte_dirty, for example so flush TLB + * forcefully if we detect parallel PTE batching threads. + */ + bool force = mm_tlb_flush_nested(tlb->mm); + + arch_tlb_finish_mmu(tlb, start, end, force); + dec_tlb_flush_pending(tlb->mm); +} |