From: "Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
To: benh@kernel•crashing.org, paulus@samba•org, mpe@ellerman•id.au
Cc: linuxppc-dev@lists•ozlabs.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux•vnet.ibm.com>
Subject: [PATCH 2/3] powerpc/mm/radix: Use ptep_get_and_clear_full when clearing pte for full mm
Date: Thu, 9 Feb 2017 08:28:20 +0530 [thread overview]
Message-ID: <1486609101-5231-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1486609101-5231-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
This helps us to do some optimization for application exit case, where we can
skip the DD1 style pte update sequence.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux•vnet.ibm.com>
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 17 +++++++++++++++++
arch/powerpc/include/asm/book3s/64/radix.h | 23 ++++++++++++++++++++++-
2 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 6f15bde94da2..e91ada786d48 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -373,6 +373,23 @@ static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
return __pte(old);
}
+#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
+static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep, int full)
+{
+ if (full && radix_enabled()) {
+ /*
+ * Let's skip the DD1 style pte update here. We know that
+ * this is a full mm pte clear and hence can be sure there is
+ * no parallel set_pte.
+ */
+ return radix__ptep_get_and_clear_full(mm, addr, ptep, full);
+ }
+ return ptep_get_and_clear(mm, addr, ptep);
+}
+
+
static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t * ptep)
{
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 70a3cdcdbe47..fcf822d6c204 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -139,7 +139,7 @@ static inline unsigned long radix__pte_update(struct mm_struct *mm,
unsigned long new_pte;
- old_pte = __radix_pte_update(ptep, ~0, 0);
+ old_pte = __radix_pte_update(ptep, ~0ul, 0);
/*
* new value of pte
*/
@@ -157,6 +157,27 @@ static inline unsigned long radix__pte_update(struct mm_struct *mm,
return old_pte;
}
+static inline pte_t radix__ptep_get_and_clear_full(struct mm_struct *mm,
+ unsigned long addr,
+ pte_t *ptep, int full)
+{
+ unsigned long old_pte;
+
+ if (full) {
+ /*
+ * If we are trying to clear the pte, we can skip
+ * the DD1 pte update sequence and batch the tlb flush. The
+ * tlb flush batching is done by mmu gather code. We
+ * still keep the cmp_xchg update to make sure we get
+ * correct R/C bit which might be updated via Nest MMU.
+ */
+ old_pte = __radix_pte_update(ptep, ~0ul, 0);
+ } else
+ old_pte = radix__pte_update(mm, addr, ptep, ~0ul, 0, 0);
+
+ return __pte(old_pte);
+}
+
/*
* Set the dirty and/or accessed bits atomically in a linux PTE, this
* function doesn't need to invalidate tlb.
--
2.7.4
next prev parent reply other threads:[~2017-02-09 2:58 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-09 2:58 [PATCH 1/3] powerpc/mm/radix: Update pte update sequence for pte clear case Aneesh Kumar K.V
2017-02-09 2:58 ` Aneesh Kumar K.V [this message]
2017-02-14 4:17 ` [PATCH 2/3] powerpc/mm/radix: Use ptep_get_and_clear_full when clearing pte for full mm Michael Neuling
2017-02-09 2:58 ` [PATCH 3/3] powerpc/mm/radix: Skip ptesync in pte update helpers Aneesh Kumar K.V
2017-02-14 4:17 ` Michael Neuling
2017-02-09 3:49 ` [PATCH 1/3] powerpc/mm/radix: Update pte update sequence for pte clear case Benjamin Herrenschmidt
2017-02-09 4:15 ` Benjamin Herrenschmidt
2017-02-09 4:34 ` Aneesh Kumar K.V
2017-02-14 4:17 ` Michael Neuling
2017-02-16 5:59 ` [1/3] " Michael Ellerman
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