From: Dave Kleikamp <dave.kleikamp@oracle.com>
Date: Tue, 18 Jun 2013 14:05:36 +0000 (-0500)
Subject: sparc: tsb must be flushed before tlb
X-Git-Tag: v6.6-pxa1908~25283^2
X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=23a01138efe216f8084cfaa74b0b90dd4b097441;p=linux.git

sparc: tsb must be flushed before tlb

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>
---

diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 83d89bcb44af..37e7bc4c95b3 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;
 	}