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| author | Peter Zijlstra <peterz@infradead.org> | 2018-08-22 17:30:14 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-12-16 22:08:52 +0000 |
| commit | 52c01119020ede1f4f935ed1f81f7f418eca69b1 (patch) | |
| tree | 8a3dd2980ca8710ffc42c996d76afcfa080ce389 /mm | |
| parent | 32e0dc1b86fad6e0da8691c90af2e0d2a1160329 (diff) | |
| download | linux-stable-52c01119020ede1f4f935ed1f81f7f418eca69b1.tar.gz linux-stable-52c01119020ede1f4f935ed1f81f7f418eca69b1.tar.bz2 linux-stable-52c01119020ede1f4f935ed1f81f7f418eca69b1.zip | |
mm/tlb: Remove tlb_remove_table() non-concurrent condition
commit a6f572084fbee8b30f91465f4a085d7a90901c57 upstream.
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 9 |
1 files changed, 0 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c index 582d689c12b6..62c2c8a148b0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -359,15 +359,6 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table) tlb->need_flush = 1; - /* - * 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) { |