[PATH V2 3/6] arm: mm: Enable HAVE_RCU_TABLE_FREE logic
From: catalin.marinas@arm.com (Catalin Marinas)
Date: 2014-08-27 11:50:50
Also in:
linux-arch, linux-mm
On Thu, Aug 21, 2014 at 04:43:29PM +0100, Steve Capper wrote:
quoted hunk ↗ jump to hunk
--- a/arch/arm/include/asm/tlb.h +++ b/arch/arm/include/asm/tlb.h@@ -35,12 +35,39 @@ #define MMU_GATHER_BUNDLE 8 +#ifdef CONFIG_HAVE_RCU_TABLE_FREE +static inline void __tlb_remove_table(void *_table) +{ + free_page_and_swap_cache((struct page *)_table); +} + +struct mmu_table_batch { + struct rcu_head rcu; + unsigned int nr; + void *tables[0]; +}; + +#define MAX_TABLE_BATCH \ + ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *)) + +extern void tlb_table_flush(struct mmu_gather *tlb); +extern void tlb_remove_table(struct mmu_gather *tlb, void *table); + +#define tlb_remove_entry(tlb, entry) tlb_remove_table(tlb, entry) +#else +#define tlb_remove_entry(tlb, entry) tlb_remove_page(tlb, entry) +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ + /* * TLB handling. This allows us to remove pages from the page * tables, and efficiently handle the TLB issues. */ struct mmu_gather { struct mm_struct *mm; +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + struct mmu_table_batch *batch; + unsigned int need_flush; +#endif
We add need_flush here just because it is set by tlb_remove_table() but it won't actually be checked by anything since arch/arm uses its own version of tlb_flush_mmu(). But I wouldn't go for #ifdefs in the core code either. We should (as a separate patchset) convert arch/arm to generic mmu_gather. I know Russell had objections in the past but mmu_gather has evolved since and it's not longer inefficient (I think the only case is shift_arg_pages but that's pretty much lost in the noise). For this patch: Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>