From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: akpm@linux-foundation.org, npiggin@gmail.com, mpe@ellerman.id.au,
peterz@infradead.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush
Date: Tue, 17 Dec 2019 12:47:13 +0530 [thread overview]
Message-ID: <20191217071713.93399-2-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20191217071713.93399-1-aneesh.kumar@linux.ibm.com>
On tlb_finish_mmu() kernel does a tlb flush before mmu gather table invalidate.
The mmu gather table invalidate depending on kernel config also does another
TLBI. Avoid the later on tlb_finish_mmu().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
mm/mmu_gather.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 7c1b8f67af7b..7e2bd43b9084 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -143,17 +143,23 @@ static void tlb_remove_table_rcu(struct rcu_head *head)
free_page((unsigned long)batch);
}
-static void tlb_table_flush(struct mmu_gather *tlb)
+static void __tlb_table_flush(struct mmu_gather *tlb, bool table_inval)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch) {
- tlb_table_invalidate(tlb);
+ if (table_inval)
+ tlb_table_invalidate(tlb);
call_rcu(&(*batch)->rcu, tlb_remove_table_rcu);
*batch = NULL;
}
}
+static void tlb_table_flush(struct mmu_gather *tlb)
+{
+ __tlb_table_flush(tlb, true);
+}
+
void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
@@ -178,7 +184,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
static void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
- tlb_table_flush(tlb);
+ __tlb_table_flush(tlb, false);
#endif
#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
tlb_batch_pages_flush(tlb);
--
2.23.0
WARNING: multiple messages have this Message-ID (diff)
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: akpm@linux-foundation.org, npiggin@gmail.com, mpe@ellerman.id.au,
peterz@infradead.org
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush
Date: Tue, 17 Dec 2019 12:47:13 +0530 [thread overview]
Message-ID: <20191217071713.93399-2-aneesh.kumar@linux.ibm.com> (raw)
In-Reply-To: <20191217071713.93399-1-aneesh.kumar@linux.ibm.com>
On tlb_finish_mmu() kernel does a tlb flush before mmu gather table invalidate.
The mmu gather table invalidate depending on kernel config also does another
TLBI. Avoid the later on tlb_finish_mmu().
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
mm/mmu_gather.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 7c1b8f67af7b..7e2bd43b9084 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -143,17 +143,23 @@ static void tlb_remove_table_rcu(struct rcu_head *head)
free_page((unsigned long)batch);
}
-static void tlb_table_flush(struct mmu_gather *tlb)
+static void __tlb_table_flush(struct mmu_gather *tlb, bool table_inval)
{
struct mmu_table_batch **batch = &tlb->batch;
if (*batch) {
- tlb_table_invalidate(tlb);
+ if (table_inval)
+ tlb_table_invalidate(tlb);
call_rcu(&(*batch)->rcu, tlb_remove_table_rcu);
*batch = NULL;
}
}
+static void tlb_table_flush(struct mmu_gather *tlb)
+{
+ __tlb_table_flush(tlb, true);
+}
+
void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
struct mmu_table_batch **batch = &tlb->batch;
@@ -178,7 +184,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
static void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
- tlb_table_flush(tlb);
+ __tlb_table_flush(tlb, false);
#endif
#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
tlb_batch_pages_flush(tlb);
--
2.23.0
next prev parent reply other threads:[~2019-12-17 7:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 7:17 [RFC PATCH 1/2] mm/mmu_gather: Invalidate TLB correctly on batch allocation failure and flush Aneesh Kumar K.V
2019-12-17 7:17 ` Aneesh Kumar K.V
2019-12-17 7:17 ` Aneesh Kumar K.V [this message]
2019-12-17 7:17 ` [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush Aneesh Kumar K.V
2019-12-17 8:58 ` Peter Zijlstra
2019-12-17 8:58 ` Peter Zijlstra
2019-12-17 10:15 ` Aneesh Kumar K.V
2019-12-17 10:15 ` Aneesh Kumar K.V
2019-12-17 12:34 ` Peter Zijlstra
2019-12-17 12:34 ` Peter Zijlstra
2019-12-17 20:12 ` [PATCH] asm-generic/tlb: Avoid potential double flush Peter Zijlstra
2019-12-17 20:12 ` Peter Zijlstra
2019-12-17 9:09 ` [RFC PATCH 1/2] mm/mmu_gather: Invalidate TLB correctly on batch allocation failure and flush Peter Zijlstra
2019-12-17 9:09 ` Peter Zijlstra
2019-12-17 10:48 ` Aneesh Kumar K.V
2019-12-17 10:48 ` Aneesh Kumar K.V
2019-12-17 12:35 ` Peter Zijlstra
2019-12-17 12:35 ` Peter Zijlstra
2019-12-18 5:22 ` Aneesh Kumar K.V
2019-12-18 5:22 ` Aneesh Kumar K.V
2019-12-18 9:01 ` Peter Zijlstra
2019-12-18 9:01 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2019-12-17 7:16 Aneesh Kumar K.V
2019-12-17 7:16 ` [RFC PATCH 2/2] mm/mmu_gather: Avoid multiple page walk cache flush Aneesh Kumar K.V
2019-12-17 7:16 ` Aneesh Kumar K.V
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