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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 /mm
parent2c95523c0f0ca7c2f157a07f0c03b6bbba13fee6 (diff)
downloadop-kernel-dev-29eb77825cc7da8d45b642de2de3d423dc8a363f.zip
op-kernel-dev-29eb77825cc7da8d45b642de2de3d423dc8a363f.tar.gz
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 'mm')
-rw-r--r--mm/memory.c9
1 files changed, 0 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 6dc1882..61a262b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -220,7 +220,6 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
tlb->start = -1UL;
tlb->end = 0;
tlb->need_flush = 0;
- tlb->fast_mode = (num_possible_cpus() == 1);
tlb->local.next = NULL;
tlb->local.nr = 0;
tlb->local.max = ARRAY_SIZE(tlb->__pages);
@@ -244,9 +243,6 @@ void tlb_flush_mmu(struct mmu_gather *tlb)
tlb_table_flush(tlb);
#endif
- if (tlb_fast_mode(tlb))
- return;
-
for (batch = &tlb->local; batch; batch = batch->next) {
free_pages_and_swap_cache(batch->pages, batch->nr);
batch->nr = 0;
@@ -288,11 +284,6 @@ int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
VM_BUG_ON(!tlb->need_flush);
- if (tlb_fast_mode(tlb)) {
- free_page_and_swap_cache(page);
- return 1; /* avoid calling tlb_flush_mmu() */
- }
-
batch = tlb->active;
batch->pages[batch->nr++] = page;
if (batch->nr == batch->max) {
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