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From: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
To: linuxppc-dev <linuxppc-dev@ozlabs.org>,
	Scott Wood <scottwood@freescale.com>, Willy Tarreau <w@1wt.eu>,
	Dan Malek <ppc6dev@digitaldans.com>
Subject: [PATCH 13/14] 8xx: Optimize TLB Miss handlers
Date: Mon, 10 Oct 2011 13:30:19 +0200	[thread overview]
Message-ID: <1318246220-4839-14-git-send-email-Joakim.Tjernlund@transmode.se> (raw)
In-Reply-To: <1318246220-4839-1-git-send-email-Joakim.Tjernlund@transmode.se>

Only update pte w.r.t ACCESSED if it isn't already set
Wrap ACCESSED with #ifndef NO_SWAP for too ease optimization.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
---
 arch/ppc/kernel/head_8xx.S |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/ppc/kernel/head_8xx.S b/arch/ppc/kernel/head_8xx.S
index 0f2101d..36089cc 100644
--- a/arch/ppc/kernel/head_8xx.S
+++ b/arch/ppc/kernel/head_8xx.S
@@ -377,10 +377,14 @@ InstructionTLBMiss:
 	mfspr	r21, MD_TWC	/* ....and get the pte address */
 	lwz	r20, 0(r21)	/* Get the pte */
 
-#if 1
+#ifndef NO_SWAP
 	/* if !swap, you can delete this */
+	andi.	r21, r20, _PAGE_ACCESSED	/* test ACCESSED bit */
+	bne+	4f		/* Branch if set */
+	mfspr	r21, MD_TWC	/* get the pte address */
 	rlwimi	r20, r20, 5, _PAGE_PRESENT<<5	/* Copy PRESENT to ACCESSED */
 	stw	r20, 0(r21)	/* Update pte */
+4:
 #endif
 	/* The Linux PTE won't go exactly into the MMU TLB.
 	 * Software indicator bits 21 and 28 must be clear.
@@ -450,11 +454,14 @@ DataStoreTLBMiss:
 	DO_8xx_CPU6(0x3b80, r3)
 	mtspr	MD_TWC, r21
 
-#if 1
+#ifndef NO_SWAP
 	/* if !swap, you can delete this */
+	andi.	r21, r20, _PAGE_ACCESSED	/* test ACCESSED bit */
+	bne+	4f		/* Branch if set */
 	mfspr	r21, MD_TWC	/* get the pte address */
 	rlwimi	r20, r20, 5, _PAGE_PRESENT<<5	/* Copy PRESENT to ACCESSED */
 	stw	r20, 0(r21)	/* Update pte */
+4:
 #endif
 
 	/* Honour kernel RO, User NA */
-- 
1.7.3.4

  parent reply	other threads:[~2011-10-10 11:30 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-10 11:30 [PATCH 00/14] Backport 8xx TLB to 2.4 Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 01/14] 8xx: Use a macro to simpliy CPU6 errata code Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 02/14] 8xx: Tag DAR with 0x00f0 to catch buggy instructions Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 03/14] 8xx: invalidate non present TLBs Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 04/14] 8xx: Fix CONFIG_PIN_TLB Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 05/14] 8xx: Update TLB asm so it behaves as linux mm expects Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 06/14] 8xx: Fixup DAR from buggy dcbX instructions Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 07/14] 8xx: CPU6 errata make DTLB error too big to fit Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 08/14] 8xx: Add missing Guarded setting in DTLB Error Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 09/14] 8xx: Restore _PAGE_WRITETHRU Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 10/14] 8xx: Set correct HW pte flags in DTLB Error too Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 11/14] 8xx: start using dcbX instructions in various copy routines Joakim Tjernlund
2011-10-10 11:30 ` [PATCH 12/14] 8xx: Use symbolic constants in TLB asm Joakim Tjernlund
2011-10-10 11:30 ` Joakim Tjernlund [this message]
2011-10-10 11:30 ` [PATCH 14/14] 8xx: The TLB miss handler manages ACCESSED correctly Joakim Tjernlund
2011-10-10 12:30 ` [PATCH 00/14] Backport 8xx TLB to 2.4 Willy Tarreau
2011-12-11 17:19 ` Joakim Tjernlund
2011-12-11 17:33   ` Willy Tarreau
2012-02-08  8:44     ` Joakim Tjernlund
2012-02-08  9:44       ` Willy Tarreau
2012-02-08 11:39         ` Joakim Tjernlund
2012-02-08 12:26           ` Willy Tarreau
2012-04-09 13:08           ` Willy Tarreau

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