[PATCH 45/75] sparc: tsb must be flushed before tlb

From: Kamal Mostafa
Date: Tue Jul 30 2013 - 14:57:34 EST -stable review patch. If anyone has any objections, please let me know.


From: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>

commit 23a01138efe216f8084cfaa74b0b90dd4b097441 upstream.

This fixes a race where a cpu may re-load a tlb from a stale tsb right
after it has been flushed by a remote function call.

I still see some instability when stressing the system with parallel
kernel builds while creating memory pressure by writing to
/proc/sys/vm/nr_hugepages, but this patch improves the stability

Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Acked-by: Bob Picco <bob.picco@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
arch/sparc/mm/tlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 83d89bc..37e7bc4 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -85,8 +85,8 @@ static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr,

if (!tb->active) {
- global_flush_tlb_page(mm, vaddr);
flush_tsb_user_page(mm, vaddr);
+ global_flush_tlb_page(mm, vaddr);
goto out;


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