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authorPeter Zijlstra <peterz@infradead.org>2013-06-05 12:26:50 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2013-06-06 10:07:26 +0900
commit29eb77825cc7da8d45b642de2de3d423dc8a363f (patch)
tree689c3c9f8b34f8023899ba8c230ea04c4dc21e54 /arch/arm
parent2c95523c0f0ca7c2f157a07f0c03b6bbba13fee6 (diff)
arch, mm: Remove tlb_fast_mode()
Since the introduction of preemptible mmu_gather TLB fast mode has been broken. TLB fast mode relies on there being absolutely no concurrency; it frees pages first and invalidates TLBs later. However now we can get concurrency and stuff goes *bang*. This patch removes all tlb_fast_mode() code; it was found the better option vs trying to patch the hole by entangling tlb invalidation with the scheduler. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Tony Luck <tony.luck@intel.com> Reported-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/include/asm/tlb.h27
1 files changed, 4 insertions, 23 deletions
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h
index 99a19512ee2..bdf2b8458ec 100644
--- a/arch/arm/include/asm/tlb.h
+++ b/arch/arm/include/asm/tlb.h
@@ -33,18 +33,6 @@
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
-/*
- * We need to delay page freeing for SMP as other CPUs can access pages
- * which have been removed but not yet had their TLB entries invalidated.
- * Also, as ARMv7 speculative prefetch can drag new entries into the TLB,
- * we need to apply this same delaying tactic to ensure correct operation.
- */
-#if defined(CONFIG_SMP) || defined(CONFIG_CPU_32v7)
-#define tlb_fast_mode(tlb) 0
-#else
-#define tlb_fast_mode(tlb) 1
-#endif
-
#define MMU_GATHER_BUNDLE 8
/*
@@ -112,12 +100,10 @@ static inline void __tlb_alloc_page(struct mmu_gather *tlb)
static inline void tlb_flush_mmu(struct mmu_gather *tlb)
{
tlb_flush(tlb);
- if (!tlb_fast_mode(tlb)) {
- free_pages_and_swap_cache(tlb->pages, tlb->nr);
- tlb->nr = 0;
- if (tlb->pages == tlb->local)
- __tlb_alloc_page(tlb);
- }
+ free_pages_and_swap_cache(tlb->pages, tlb->nr);
+ tlb->nr = 0;
+ if (tlb->pages == tlb->local)
+ __tlb_alloc_page(tlb);
}
static inline void
@@ -178,11 +164,6 @@ tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
- if (tlb_fast_mode(tlb)) {
- free_page_and_swap_cache(page);
- return 1; /* avoid calling tlb_flush_mmu */
- }
-
tlb->pages[tlb->nr++] = page;
VM_BUG_ON(tlb->nr > tlb->max);
return tlb->max - tlb->nr;