From 952a31c9e6fa963eabf3692f31a769e59f4c8303 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Tue, 18 Sep 2018 14:51:50 +0200 Subject: asm-generic/tlb: Introduce CONFIG_HAVE_MMU_GATHER_NO_GATHER=y Add the Kconfig option HAVE_MMU_GATHER_NO_GATHER to the generic mmu_gather code. If the option is set the mmu_gather will not track individual pages for delayed page free anymore. A platform that enables the option needs to provide its own implementation of the __tlb_remove_page_size() function to free pages. No change in behavior intended. Signed-off-by: Martin Schwidefsky Signed-off-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: aneesh.kumar@linux.vnet.ibm.com Cc: heiko.carstens@de.ibm.com Cc: linux@armlinux.org.uk Cc: npiggin@gmail.com Link: http://lkml.kernel.org/r/20180918125151.31744-2-schwidefsky@de.ibm.com Signed-off-by: Ingo Molnar --- mm/mmu_gather.c | 107 +++++++++++++++++++++++++++++++------------------------- 1 file changed, 60 insertions(+), 47 deletions(-) (limited to 'mm/mmu_gather.c') diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 2a5322d52b0a..ab220edcd7ef 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -13,6 +13,8 @@ #ifdef HAVE_GENERIC_MMU_GATHER +#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER + static bool tlb_next_batch(struct mmu_gather *tlb) { struct mmu_gather_batch *batch; @@ -41,6 +43,56 @@ static bool tlb_next_batch(struct mmu_gather *tlb) return true; } +static void tlb_batch_pages_flush(struct mmu_gather *tlb) +{ + struct mmu_gather_batch *batch; + + 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; +} + +static void tlb_batch_list_free(struct mmu_gather *tlb) +{ + struct mmu_gather_batch *batch, *next; + + for (batch = tlb->local.next; batch; batch = next) { + next = batch->next; + free_pages((unsigned long)batch, 0); + } + tlb->local.next = NULL; +} + +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); + +#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE + VM_WARN_ON(tlb->page_size != page_size); +#endif + + 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_MMU_GATHER_NO_GATHER */ + void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end) { @@ -48,12 +100,15 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, /* Is it from 0 to ~0? */ tlb->fullmm = !(start | (end+1)); + +#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER 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; +#endif #ifdef CONFIG_HAVE_RCU_TABLE_FREE tlb->batch = NULL; @@ -67,16 +122,12 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, 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; +#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER + tlb_batch_pages_flush(tlb); +#endif } void tlb_flush_mmu(struct mmu_gather *tlb) @@ -92,8 +143,6 @@ void tlb_flush_mmu(struct mmu_gather *tlb) 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); @@ -103,45 +152,9 @@ void arch_tlb_finish_mmu(struct mmu_gather *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); - -#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE - VM_WARN_ON(tlb->page_size != page_size); +#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER + tlb_batch_list_free(tlb); #endif - - 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 */ -- cgit v1.2.3-55-g7522