[PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Wanpeng Li]

Changelog:
 v7 -> v8:
  * remove references to it in Documentation/sysctl/kernel.txt 

commit 887c290e (sched/numa: Decide whether to favour task or group weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 Documentation/sysctl/kernel.txt |    5 -----
 include/linux/sched/sysctl.h    |    1 -
 kernel/sched/fair.c             |    9 ---------
 kernel/sysctl.c                 |    7 -------
 4 files changed, 0 insertions(+), 22 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 26b7ee4..6d48640 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -428,11 +428,6 @@ rate for each task.
 numa_balancing_scan_size_mb is how many megabytes worth of pages are
 scanned for a given scan.
 
-numa_balancing_settle_count is how many scan periods must complete before
-the schedule balancer stops pushing the task towards a preferred node. This
-gives the scheduler a chance to place the task on an alternative node if the
-preferred node is overloaded.
-
 numa_balancing_migrate_deferred is how many page migrations get skipped
 unconditionally, after a page migration is skipped because a page is shared
 with other tasks. This reduces page migration overhead, and determines
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 41467f8..31e0193 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -48,7 +48,6 @@ extern unsigned int sysctl_numa_balancing_scan_delay;
 extern unsigned int sysctl_numa_balancing_scan_period_min;
 extern unsigned int sysctl_numa_balancing_scan_period_max;
 extern unsigned int sysctl_numa_balancing_scan_size;
-extern unsigned int sysctl_numa_balancing_settle_count;
 
 #ifdef CONFIG_SCHED_DEBUG
 extern unsigned int sysctl_sched_migration_cost;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fd773ad..acdef27 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -886,15 +886,6 @@ static unsigned int task_scan_max(struct task_struct *p)
 	return max(smin, smax);
 }
 
-/*
- * Once a preferred node is selected the scheduler balancer will prefer moving
- * a task to that node for sysctl_numa_balancing_settle_count number of PTE
- * scans. This will give the process the chance to accumulate more faults on
- * the preferred node but still allow the scheduler to move the task again if
- * the nodes CPUs are overloaded.
- */
-unsigned int sysctl_numa_balancing_settle_count __read_mostly = 4;
-
 static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
 {
 	rq->nr_numa_running += (p->numa_preferred_nid != -1);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 34a6047..c8da99f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -385,13 +385,6 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 	{
-		.procname       = "numa_balancing_settle_count",
-		.data           = &sysctl_numa_balancing_settle_count,
-		.maxlen         = sizeof(unsigned int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
-	},
-	{
 		.procname       = "numa_balancing_migrate_deferred",
 		.data           = &sysctl_numa_balancing_migrate_deferred,
 		.maxlen         = sizeof(unsigned int),
-- 
1.7.7.6

[PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Wanpeng Li]

Changelog:
 v7 -> v8:
  * remove references to it in Documentation/sysctl/kernel.txt 

commit 887c290e (sched/numa: Decide whether to favour task or group weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 Documentation/sysctl/kernel.txt |    5 -----
 include/linux/sched/sysctl.h    |    1 -
 kernel/sched/fair.c             |    9 ---------
 kernel/sysctl.c                 |    7 -------
 4 files changed, 0 insertions(+), 22 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 26b7ee4..6d48640 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -428,11 +428,6 @@ rate for each task.
 numa_balancing_scan_size_mb is how many megabytes worth of pages are
 scanned for a given scan.
 
-numa_balancing_settle_count is how many scan periods must complete before
-the schedule balancer stops pushing the task towards a preferred node. This
-gives the scheduler a chance to place the task on an alternative node if the
-preferred node is overloaded.
-
 numa_balancing_migrate_deferred is how many page migrations get skipped
 unconditionally, after a page migration is skipped because a page is shared
 with other tasks. This reduces page migration overhead, and determines
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 41467f8..31e0193 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -48,7 +48,6 @@ extern unsigned int sysctl_numa_balancing_scan_delay;
 extern unsigned int sysctl_numa_balancing_scan_period_min;
 extern unsigned int sysctl_numa_balancing_scan_period_max;
 extern unsigned int sysctl_numa_balancing_scan_size;
-extern unsigned int sysctl_numa_balancing_settle_count;
 
 #ifdef CONFIG_SCHED_DEBUG
 extern unsigned int sysctl_sched_migration_cost;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fd773ad..acdef27 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -886,15 +886,6 @@ static unsigned int task_scan_max(struct task_struct *p)
 	return max(smin, smax);
 }
 
-/*
- * Once a preferred node is selected the scheduler balancer will prefer moving
- * a task to that node for sysctl_numa_balancing_settle_count number of PTE
- * scans. This will give the process the chance to accumulate more faults on
- * the preferred node but still allow the scheduler to move the task again if
- * the nodes CPUs are overloaded.
- */
-unsigned int sysctl_numa_balancing_settle_count __read_mostly = 4;
-
 static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
 {
 	rq->nr_numa_running += (p->numa_preferred_nid != -1);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 34a6047..c8da99f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -385,13 +385,6 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 	{
-		.procname       = "numa_balancing_settle_count",
-		.data           = &sysctl_numa_balancing_settle_count,
-		.maxlen         = sizeof(unsigned int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
-	},
-	{
 		.procname       = "numa_balancing_migrate_deferred",
 		.data           = &sysctl_numa_balancing_migrate_deferred,
 		.maxlen         = sizeof(unsigned int),
-- 
1.7.7.6

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[PATCH v8 2/4] sched/numa: use wrapper function task_node to get node which task is on

[Wanpeng Li]

Changelog:
 v2 -> v3:
  * tranlate cpu_to_node(task_cpu(p)) to task_node(p) in sched/debug.c

Use wrapper function task_node to get node which task is on.

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/debug.c |    2 +-
 kernel/sched/fair.c  |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 5c34d18..374fe04 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -139,7 +139,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 		0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
 #endif
 #ifdef CONFIG_NUMA_BALANCING
-	SEQ_printf(m, " %d", cpu_to_node(task_cpu(p)));
+	SEQ_printf(m, " %d", task_node(p));
 #endif
 #ifdef CONFIG_CGROUP_SCHED
 	SEQ_printf(m, " %s", task_group_path(task_group(p)));
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index acdef27..c3f6ff9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1216,7 +1216,7 @@ static int task_numa_migrate(struct task_struct *p)
 	 * elsewhere, so there is no point in (re)trying.
 	 */
 	if (unlikely(!sd)) {
-		p->numa_preferred_nid = cpu_to_node(task_cpu(p));
+		p->numa_preferred_nid = task_node(p);
 		return -EINVAL;
 	}
 
@@ -1283,7 +1283,7 @@ static void numa_migrate_preferred(struct task_struct *p)
 	p->numa_migrate_retry = jiffies + HZ;
 
 	/* Success if task is already running on preferred CPU */
-	if (cpu_to_node(task_cpu(p)) == p->numa_preferred_nid)
+	if (task_node(p) == p->numa_preferred_nid)
 		return;
 
 	/* Otherwise, try migrate to a CPU on the preferred node */
-- 
1.7.7.6

[PATCH v8 2/4] sched/numa: use wrapper function task_node to get node which task is on

[Wanpeng Li]

Changelog:
 v2 -> v3:
  * tranlate cpu_to_node(task_cpu(p)) to task_node(p) in sched/debug.c

Use wrapper function task_node to get node which task is on.

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/debug.c |    2 +-
 kernel/sched/fair.c  |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 5c34d18..374fe04 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -139,7 +139,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 		0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
 #endif
 #ifdef CONFIG_NUMA_BALANCING
-	SEQ_printf(m, " %d", cpu_to_node(task_cpu(p)));
+	SEQ_printf(m, " %d", task_node(p));
 #endif
 #ifdef CONFIG_CGROUP_SCHED
 	SEQ_printf(m, " %s", task_group_path(task_group(p)));
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index acdef27..c3f6ff9 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1216,7 +1216,7 @@ static int task_numa_migrate(struct task_struct *p)
 	 * elsewhere, so there is no point in (re)trying.
 	 */
 	if (unlikely(!sd)) {
-		p->numa_preferred_nid = cpu_to_node(task_cpu(p));
+		p->numa_preferred_nid = task_node(p);
 		return -EINVAL;
 	}
 
@@ -1283,7 +1283,7 @@ static void numa_migrate_preferred(struct task_struct *p)
 	p->numa_migrate_retry = jiffies + HZ;
 
 	/* Success if task is already running on preferred CPU */
-	if (cpu_to_node(task_cpu(p)) == p->numa_preferred_nid)
+	if (task_node(p) == p->numa_preferred_nid)
 		return;
 
 	/* Otherwise, try migrate to a CPU on the preferred node */
-- 
1.7.7.6

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[PATCH v8 3/4] sched/numa: use wrapper function task_faults_idx to calculate index in group_faults

[Wanpeng Li]

Use wrapper function task_faults_idx to calculate index in group_faults.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/fair.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c3f6ff9..8a00879 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -935,7 +935,8 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
 	if (!p->numa_group)
 		return 0;
 
-	return p->numa_group->faults[2*nid] + p->numa_group->faults[2*nid+1];
+	return p->numa_group->faults[task_faults_idx(nid, 0)] +
+		p->numa_group->faults[task_faults_idx(nid, 1)];
 }
 
 /*
-- 
1.7.7.6

[PATCH v8 3/4] sched/numa: use wrapper function task_faults_idx to calculate index in group_faults

[Wanpeng Li]

Use wrapper function task_faults_idx to calculate index in group_faults.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/fair.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c3f6ff9..8a00879 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -935,7 +935,8 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
 	if (!p->numa_group)
 		return 0;
 
-	return p->numa_group->faults[2*nid] + p->numa_group->faults[2*nid+1];
+	return p->numa_group->faults[task_faults_idx(nid, 0)] +
+		p->numa_group->faults[task_faults_idx(nid, 1)];
 }
 
 /*
-- 
1.7.7.6

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[PATCH v8 4/4] sched/numa: fix period_slot recalculation

[Wanpeng Li]

Changelog:
 v3 -> v4:
  * remove period_slot recalculation

The original code is as intended and was meant to scale the difference
between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting
the scan period. The period_slot recalculation can be dropped.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/fair.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8a00879..e7ca79a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1356,7 +1356,6 @@ static void update_task_scan_period(struct task_struct *p,
 		 * scanning faster if shared accesses dominate as it may
 		 * simply bounce migrations uselessly
 		 */
-		period_slot = DIV_ROUND_UP(diff, NUMA_PERIOD_SLOTS);
 		ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared));
 		diff = (diff * ratio) / NUMA_PERIOD_SLOTS;
 	}
-- 
1.7.7.6

[PATCH v8 4/4] sched/numa: fix period_slot recalculation

[Wanpeng Li]

Changelog:
 v3 -> v4:
  * remove period_slot recalculation

The original code is as intended and was meant to scale the difference
between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting
the scan period. The period_slot recalculation can be dropped.

Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
 kernel/sched/fair.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8a00879..e7ca79a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1356,7 +1356,6 @@ static void update_task_scan_period(struct task_struct *p,
 		 * scanning faster if shared accesses dominate as it may
 		 * simply bounce migrations uselessly
 		 */
-		period_slot = DIV_ROUND_UP(diff, NUMA_PERIOD_SLOTS);
 		ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared));
 		diff = (diff * ratio) / NUMA_PERIOD_SLOTS;
 	}
-- 
1.7.7.6

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Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Peter Zijlstra]

On Thu, Dec 12, 2013 at 03:23:23PM +0800, Wanpeng Li wrote:
> Changelog:
>  v7 -> v8:
>   * remove references to it in Documentation/sysctl/kernel.txt 

Please do not put such bits in the changelog proper, but put them below
the --- line, that way they disappear automagically.

Applied all 4, thanks!

Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Peter Zijlstra]

On Thu, Dec 12, 2013 at 03:23:23PM +0800, Wanpeng Li wrote:
> Changelog:
>  v7 -> v8:
>   * remove references to it in Documentation/sysctl/kernel.txt 

Please do not put such bits in the changelog proper, but put them below
the --- line, that way they disappear automagically.

Applied all 4, thanks!

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Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Wanpeng Li]

Hi Peter,
On Fri, Dec 13, 2013 at 07:09:33PM +0100, Peter Zijlstra wrote:
>On Thu, Dec 12, 2013 at 03:23:23PM +0800, Wanpeng Li wrote:
>> Changelog:
>>  v7 -> v8:
>>   * remove references to it in Documentation/sysctl/kernel.txt 
>
>Please do not put such bits in the changelog proper, but put them below
>the --- line, that way they disappear automagically.
>

Do you mean something like: 

commit 887c290e (sched/numa: Decide whether to favour task or group
weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.

Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
---
Changelog:
 v7 -> v8:
   * remove references to it in Documentation/sysctl/kernel.txt
---
Documentation/sysctl/kernel.txt |    5 -----
include/linux/sched/sysctl.h    |    1 -
kernel/sched/fair.c             |    9 ---------
kernel/sysctl.c                 |    7 -------
4 files changed, 0 insertions(+), 22 deletions(-)

>Applied all 4, thanks!

Thanks. ;-)

Regards,
Wanpeng Li 


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Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Peter Zijlstra]

On Sun, Dec 15, 2013 at 04:41:10PM +0800, Wanpeng Li wrote:
> Do you mean something like: 
> 
> commit 887c290e (sched/numa: Decide whether to favour task or group
> weights
> based on swap candidate relationships) drop the check against
> sysctl_numa_balancing_settle_count, this patch remove the sysctl.
> 
> Acked-by: Mel Gorman <mgorman@suse.de>
> Reviewed-by: Rik van Riel <riel@redhat.com>
> Acked-by: David Rientjes <rientjes@google.com>
> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
> ---
> Changelog:
>  v7 -> v8:
>    * remove references to it in Documentation/sysctl/kernel.txt
> ---

No need to insert another --- line, just the one below the SoB,

> Documentation/sysctl/kernel.txt |    5 -----
> include/linux/sched/sysctl.h    |    1 -
> kernel/sched/fair.c             |    9 ---------
> kernel/sysctl.c                 |    7 -------
> 4 files changed, 0 insertions(+), 22 deletions(-)

Everything between --- and the patch proper (usually started with an
Index line or other diff syntax thingy), including this diffstat you
have, will be made to disappear.

But yes indeed. The Changelog should describe the patch as is, and the
differences between this and the previous version are relevant only to
the reviewer who saw the previous version too. But once we commit the
patch, the previous version ceases to exist (in the commit history) and
therefore such comments loose their intrinsic meaning and should go away
too.

Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Peter Zijlstra]

On Sun, Dec 15, 2013 at 04:41:10PM +0800, Wanpeng Li wrote:
> Do you mean something like: 
> 
> commit 887c290e (sched/numa: Decide whether to favour task or group
> weights
> based on swap candidate relationships) drop the check against
> sysctl_numa_balancing_settle_count, this patch remove the sysctl.
> 
> Acked-by: Mel Gorman <mgorman@suse.de>
> Reviewed-by: Rik van Riel <riel@redhat.com>
> Acked-by: David Rientjes <rientjes@google.com>
> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
> ---
> Changelog:
>  v7 -> v8:
>    * remove references to it in Documentation/sysctl/kernel.txt
> ---

No need to insert another --- line, just the one below the SoB,

> Documentation/sysctl/kernel.txt |    5 -----
> include/linux/sched/sysctl.h    |    1 -
> kernel/sched/fair.c             |    9 ---------
> kernel/sysctl.c                 |    7 -------
> 4 files changed, 0 insertions(+), 22 deletions(-)

Everything between --- and the patch proper (usually started with an
Index line or other diff syntax thingy), including this diffstat you
have, will be made to disappear.

But yes indeed. The Changelog should describe the patch as is, and the
differences between this and the previous version are relevant only to
the reviewer who saw the previous version too. But once we commit the
patch, the previous version ceases to exist (in the commit history) and
therefore such comments loose their intrinsic meaning and should go away
too.

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Re: [PATCH v8 1/4] sched/numa: drop sysctl_numa_balancing_settle_count sysctl

[Wanpeng Li]

On Sun, Dec 15, 2013 at 05:56:43PM +0100, Peter Zijlstra wrote:
>On Sun, Dec 15, 2013 at 04:41:10PM +0800, Wanpeng Li wrote:
>> Do you mean something like: 
>> 
>> commit 887c290e (sched/numa: Decide whether to favour task or group
>> weights
>> based on swap candidate relationships) drop the check against
>> sysctl_numa_balancing_settle_count, this patch remove the sysctl.
>> 
>> Acked-by: Mel Gorman <mgorman@suse.de>
>> Reviewed-by: Rik van Riel <riel@redhat.com>
>> Acked-by: David Rientjes <rientjes@google.com>
>> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> ---
>> Changelog:
>>  v7 -> v8:
>>    * remove references to it in Documentation/sysctl/kernel.txt
>> ---
>
>No need to insert another --- line, just the one below the SoB,
>
>> Documentation/sysctl/kernel.txt |    5 -----
>> include/linux/sched/sysctl.h    |    1 -
>> kernel/sched/fair.c             |    9 ---------
>> kernel/sysctl.c                 |    7 -------
>> 4 files changed, 0 insertions(+), 22 deletions(-)
>
>Everything between --- and the patch proper (usually started with an
>Index line or other diff syntax thingy), including this diffstat you
>have, will be made to disappear.
>
>But yes indeed. The Changelog should describe the patch as is, and the
>differences between this and the previous version are relevant only to
>the reviewer who saw the previous version too. But once we commit the
>patch, the previous version ceases to exist (in the commit history) and
>therefore such comments loose their intrinsic meaning and should go away
>too.

Thanks for your great explanation. ;-)

Regards,
Wanpeng Li 

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[tip:sched/core] sched/numa: Drop sysctl_numa_balancing_settle_count sysctl

[tip-bot for Wanpeng Li]

Commit-ID:  1bd53a7efdc988163ec4c25f656df38dbe500632
Gitweb:     http://git.kernel.org/tip/1bd53a7efdc988163ec4c25f656df38dbe500632
Author:     Wanpeng Li <liwanp@linux.vnet.ibm.com>
AuthorDate: Thu, 12 Dec 2013 15:23:23 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Dec 2013 15:24:38 +0100

sched/numa: Drop sysctl_numa_balancing_settle_count sysctl

commit 887c290e (sched/numa: Decide whether to favour task or group weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Link: http://lkml.kernel.org/r/1386833006-6600-1-git-send-email-liwanp@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 Documentation/sysctl/kernel.txt | 5 -----
 include/linux/sched/sysctl.h    | 1 -
 kernel/sched/fair.c             | 9 ---------
 kernel/sysctl.c                 | 7 -------
 4 files changed, 22 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 26b7ee4..6d48640 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -428,11 +428,6 @@ rate for each task.
 numa_balancing_scan_size_mb is how many megabytes worth of pages are
 scanned for a given scan.
 
-numa_balancing_settle_count is how many scan periods must complete before
-the schedule balancer stops pushing the task towards a preferred node. This
-gives the scheduler a chance to place the task on an alternative node if the
-preferred node is overloaded.
-
 numa_balancing_migrate_deferred is how many page migrations get skipped
 unconditionally, after a page migration is skipped because a page is shared
 with other tasks. This reduces page migration overhead, and determines
diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h
index 41467f8..31e0193 100644
--- a/include/linux/sched/sysctl.h
+++ b/include/linux/sched/sysctl.h
@@ -48,7 +48,6 @@ extern unsigned int sysctl_numa_balancing_scan_delay;
 extern unsigned int sysctl_numa_balancing_scan_period_min;
 extern unsigned int sysctl_numa_balancing_scan_period_max;
 extern unsigned int sysctl_numa_balancing_scan_size;
-extern unsigned int sysctl_numa_balancing_settle_count;
 
 #ifdef CONFIG_SCHED_DEBUG
 extern unsigned int sysctl_sched_migration_cost;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a9185f7..fcb6c17 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -872,15 +872,6 @@ static unsigned int task_scan_max(struct task_struct *p)
 	return max(smin, smax);
 }
 
-/*
- * Once a preferred node is selected the scheduler balancer will prefer moving
- * a task to that node for sysctl_numa_balancing_settle_count number of PTE
- * scans. This will give the process the chance to accumulate more faults on
- * the preferred node but still allow the scheduler to move the task again if
- * the nodes CPUs are overloaded.
- */
-unsigned int sysctl_numa_balancing_settle_count __read_mostly = 4;
-
 static void account_numa_enqueue(struct rq *rq, struct task_struct *p)
 {
 	rq->nr_numa_running += (p->numa_preferred_nid != -1);
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 34a6047..c8da99f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -385,13 +385,6 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 	{
-		.procname       = "numa_balancing_settle_count",
-		.data           = &sysctl_numa_balancing_settle_count,
-		.maxlen         = sizeof(unsigned int),
-		.mode           = 0644,
-		.proc_handler   = proc_dointvec,
-	},
-	{
 		.procname       = "numa_balancing_migrate_deferred",
 		.data           = &sysctl_numa_balancing_migrate_deferred,
 		.maxlen         = sizeof(unsigned int),

[tip:sched/core] sched/numa: Use wrapper function task_node to get node which task is on

[tip-bot for Wanpeng Li]

Commit-ID:  de1b301a19754778ddd9f908d266ffe1c010b2cf
Gitweb:     http://git.kernel.org/tip/de1b301a19754778ddd9f908d266ffe1c010b2cf
Author:     Wanpeng Li <liwanp@linux.vnet.ibm.com>
AuthorDate: Thu, 12 Dec 2013 15:23:24 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Dec 2013 15:24:39 +0100

sched/numa: Use wrapper function task_node to get node which task is on

Use wrapper function task_node to get node which task is on.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386833006-6600-2-git-send-email-liwanp@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/debug.c | 2 +-
 kernel/sched/fair.c  | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 5c34d18..374fe04 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -139,7 +139,7 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p)
 		0LL, 0LL, 0LL, 0L, 0LL, 0L, 0LL, 0L);
 #endif
 #ifdef CONFIG_NUMA_BALANCING
-	SEQ_printf(m, " %d", cpu_to_node(task_cpu(p)));
+	SEQ_printf(m, " %d", task_node(p));
 #endif
 #ifdef CONFIG_CGROUP_SCHED
 	SEQ_printf(m, " %s", task_group_path(task_group(p)));
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fcb6c17..ebdb08b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1202,7 +1202,7 @@ static int task_numa_migrate(struct task_struct *p)
 	 * elsewhere, so there is no point in (re)trying.
 	 */
 	if (unlikely(!sd)) {
-		p->numa_preferred_nid = cpu_to_node(task_cpu(p));
+		p->numa_preferred_nid = task_node(p);
 		return -EINVAL;
 	}
 
@@ -1269,7 +1269,7 @@ static void numa_migrate_preferred(struct task_struct *p)
 	p->numa_migrate_retry = jiffies + HZ;
 
 	/* Success if task is already running on preferred CPU */
-	if (cpu_to_node(task_cpu(p)) == p->numa_preferred_nid)
+	if (task_node(p) == p->numa_preferred_nid)
 		return;
 
 	/* Otherwise, try migrate to a CPU on the preferred node */

[tip:sched/core] sched/numa: Use wrapper function task_faults_idx to calculate index in group_faults

[tip-bot for Wanpeng Li]

Commit-ID:  82897b4fd3920ffd2456731d4f2ae1406558ef4c
Gitweb:     http://git.kernel.org/tip/82897b4fd3920ffd2456731d4f2ae1406558ef4c
Author:     Wanpeng Li <liwanp@linux.vnet.ibm.com>
AuthorDate: Thu, 12 Dec 2013 15:23:25 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Dec 2013 15:24:40 +0100

sched/numa: Use wrapper function task_faults_idx to calculate index in group_faults

Use wrapper function task_faults_idx to calculate index in group_faults.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Link: http://lkml.kernel.org/r/1386833006-6600-3-git-send-email-liwanp@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/fair.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ebdb08b..37892d7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -921,7 +921,8 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
 	if (!p->numa_group)
 		return 0;
 
-	return p->numa_group->faults[2*nid] + p->numa_group->faults[2*nid+1];
+	return p->numa_group->faults[task_faults_idx(nid, 0)] +
+		p->numa_group->faults[task_faults_idx(nid, 1)];
 }
 
 /*

[tip:sched/core] sched/numa: Fix period_slot recalculation

[tip-bot for Wanpeng Li]

Commit-ID:  e777b63bbd589248eb151a3191ee92331a701385
Gitweb:     http://git.kernel.org/tip/e777b63bbd589248eb151a3191ee92331a701385
Author:     Wanpeng Li <liwanp@linux.vnet.ibm.com>
AuthorDate: Thu, 12 Dec 2013 15:23:26 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 17 Dec 2013 15:24:41 +0100

sched/numa: Fix period_slot recalculation

The original code is as intended and was meant to scale the difference
between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting
the scan period. The period_slot recalculation can be dropped.

Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Link: http://lkml.kernel.org/r/1386833006-6600-4-git-send-email-liwanp@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/fair.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 37892d7..4316af2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1342,7 +1342,6 @@ static void update_task_scan_period(struct task_struct *p,
 		 * scanning faster if shared accesses dominate as it may
 		 * simply bounce migrations uselessly
 		 */
-		period_slot = DIV_ROUND_UP(diff, NUMA_PERIOD_SLOTS);
 		ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared));
 		diff = (diff * ratio) / NUMA_PERIOD_SLOTS;
 	}