path: root/mm
diff options
authorPeter Zijlstra <peterz@infradead.org>2018-08-22 17:30:14 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-23 11:55:58 -0700
commita6f572084fbee8b30f91465f4a085d7a90901c57 (patch)
treeedfe14d7b24d0c54599e90ee493542be8a0411e9 /mm
parentdb7ddef301128dad394f1c0f77027f86ee9a4edb (diff)
mm/tlb: Remove tlb_remove_table() non-concurrent condition
Will noted that only checking mm_users is incorrect; we should also check mm_count in order to cover CPUs that have a lazy reference to this mm (and could do speculative TLB operations). If removing this turns out to be a performance issue, we can re-instate a more complete check, but in tlb_table_flush() eliding the call_rcu_sched(). Fixes: 267239116987 ("mm, powerpc: move the RCU page-table freeing into generic code") Reported-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@surriel.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
1 files changed, 0 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 9b135a35f99c..1893751cf6c0 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -375,15 +375,6 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
struct mmu_table_batch **batch = &tlb->batch;
- /*
- * When there's less then two users of this mm there cannot be a
- * concurrent page-table walk.
- */
- if (atomic_read(&tlb->mm->mm_users) < 2) {
- __tlb_remove_table(table);
- return;
- }
if (*batch == NULL) {
*batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
if (*batch == NULL) {