Patchwork [067/106] sparc: tsb must be flushed before tlb

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Submitter Luis Henriques
Date July 30, 2013, 9:31 a.m.
Message ID <1375176725-5825-68-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/263345/
State New
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Luis Henriques - July 30, 2013, 9:31 a.m.
3.5.7.18 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Kleikamp <dave.kleikamp@oracle.com>

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
significantly.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: Bob Picco <bob.picco@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ luis: backported to 3.5: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 arch/sparc/mm/tlb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index afd021e..072f553 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -115,8 +115,8 @@  no_cache_flush:
 	}
 
 	if (!tb->active) {
-		global_flush_tlb_page(mm, vaddr);
 		flush_tsb_user_page(mm, vaddr);
+		global_flush_tlb_page(mm, vaddr);
 		goto out;
 	}