[PATCH] memory-hotplug: add build zonelists when offline pages

[PATCH] memory-hotplug: add build zonelists when offline pages

[qiuxishi]

From: Xishi Qiu <qiuxishi@huawei.com>

online_pages() does build_all_zonelists() and zone_pcp_update(),
I think offline_pages() should do it too. The node has no memory
to allocate, so remove this node's zones form other nodes' zonelists.


Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
---
 mm/memory_hotplug.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index bc7e7a2..5172bd4 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -979,7 +979,11 @@ repeat:
 	if (!node_present_pages(node)) {
 		node_clear_state(node, N_HIGH_MEMORY);
 		kswapd_stop(node);
-	}
+		mutex_lock(&zonelists_mutex);
+		build_all_zonelists(NODE_DATA(node), NULL);
+		mutex_unlock(&zonelists_mutex);
+	} else
+		zone_pcp_update(zone);

 	vm_total_pages = nr_free_pagecache_pages();
 	writeback_set_ratelimit();
-- 
1.7.6.1

Re: [PATCH] memory-hotplug: add build zonelists when offline pages

[Wen Congyang]

At 08/21/2012 08:51 PM, qiuxishi Wrote:
> From: Xishi Qiu <qiuxishi@huawei.com>
> 
> online_pages() does build_all_zonelists() and zone_pcp_update(),
> I think offline_pages() should do it too. The node has no memory
> to allocate, so remove this node's zones form other nodes' zonelists.
> 
> 
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
> ---
>  mm/memory_hotplug.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index bc7e7a2..5172bd4 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -979,7 +979,11 @@ repeat:
>  	if (!node_present_pages(node)) {
>  		node_clear_state(node, N_HIGH_MEMORY);
>  		kswapd_stop(node);
> -	}
> +		mutex_lock(&zonelists_mutex);
> +		build_all_zonelists(NODE_DATA(node), NULL);

The node is still onlined now, so there is no need to pass
this node's pgdat to build_all_zonelists().

I think we should build all zonelists when the zone has no
pages.

> +		mutex_unlock(&zonelists_mutex);
> +	} else
> +		zone_pcp_update(zone);

There is more than one zone in a node. So the zone can have
no pages when the node has some pages.

And we have called drain_all_pages(), I think there is no need
to call zone_pcp_update() here.

Thanks
Wen Congyang

> 
>  	vm_total_pages = nr_free_pagecache_pages();
>  	writeback_set_ratelimit();

Re: [PATCH] memory-hotplug: add build zonelists when offline pages

[qiuxishi]

On 2012-8-22 14:15, Wen Congyang wrote:
> At 08/21/2012 08:51 PM, qiuxishi Wrote:
>> From: Xishi Qiu <qiuxishi@huawei.com>
>>
>> online_pages() does build_all_zonelists() and zone_pcp_update(),
>> I think offline_pages() should do it too. The node has no memory
>> to allocate, so remove this node's zones form other nodes' zonelists.
>>
>>
>> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
>> ---
>>  mm/memory_hotplug.c |    6 +++++-
>>  1 files changed, 5 insertions(+), 1 deletions(-)
>>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index bc7e7a2..5172bd4 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -979,7 +979,11 @@ repeat:
>>  	if (!node_present_pages(node)) {
>>  		node_clear_state(node, N_HIGH_MEMORY);
>>  		kswapd_stop(node);
>> -	}
>> +		mutex_lock(&zonelists_mutex);
>> +		build_all_zonelists(NODE_DATA(node), NULL);
> 
> The node is still onlined now, so there is no need to pass
> this node's pgdat to build_all_zonelists().
> 
> I think we should build all zonelists when the zone has no
> pages.
> 
>> +		mutex_unlock(&zonelists_mutex);
>> +	} else
>> +		zone_pcp_update(zone);
> 
> There is more than one zone in a node. So the zone can have
> no pages when the node has some pages.
> 

Yes, you are right. Here is the new patch,

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
---
 mm/memory_hotplug.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index bc7e7a2..5f6997f 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -973,8 +973,13 @@ repeat:

 	init_per_zone_wmark_min();

-	if (!populated_zone(zone))
+	if (!populated_zone(zone)) {
 		zone_pcp_reset(zone);
+		mutex_lock(&zonelists_mutex);
+		build_all_zonelists(NULL, NULL);
+		mutex_unlock(&zonelists_mutex);
+	} else
+		zone_pcp_update(zone);

 	if (!node_present_pages(node)) {
 		node_clear_state(node, N_HIGH_MEMORY);
-- 
1.7.6.1

> And we have called drain_all_pages(), I think there is no need
> to call zone_pcp_update() here.
> 
> Thanks
> Wen Congyang
> 

In zone_pcp_update(), it calculates zone_batchsize() which does
not calculated in drain_all_pages().

Thanks
Xishi Qiu

>>
>>  	vm_total_pages = nr_free_pagecache_pages();
>>  	writeback_set_ratelimit();
> 
> 

Re: [PATCH] memory-hotplug: add build zonelists when offline pages

[Wen Congyang]

At 08/22/2012 03:59 PM, qiuxishi Wrote:
> On 2012-8-22 14:15, Wen Congyang wrote:
>> > At 08/21/2012 08:51 PM, qiuxishi Wrote:
>>> >> From: Xishi Qiu <qiuxishi@huawei.com>
>>> >>
>>> >> online_pages() does build_all_zonelists() and zone_pcp_update(),
>>> >> I think offline_pages() should do it too. The node has no memory
>>> >> to allocate, so remove this node's zones form other nodes' zonelists.
>>> >>
>>> >>
>>> >> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
>>> >> ---
>>> >>  mm/memory_hotplug.c |    6 +++++-
>>> >>  1 files changed, 5 insertions(+), 1 deletions(-)
>>> >>
>>> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>> >> index bc7e7a2..5172bd4 100644
>>> >> --- a/mm/memory_hotplug.c
>>> >> +++ b/mm/memory_hotplug.c
>>> >> @@ -979,7 +979,11 @@ repeat:
>>> >>  	if (!node_present_pages(node)) {
>>> >>  		node_clear_state(node, N_HIGH_MEMORY);
>>> >>  		kswapd_stop(node);
>>> >> -	}
>>> >> +		mutex_lock(&zonelists_mutex);
>>> >> +		build_all_zonelists(NODE_DATA(node), NULL);
>> > 
>> > The node is still onlined now, so there is no need to pass
>> > this node's pgdat to build_all_zonelists().
>> > 
>> > I think we should build all zonelists when the zone has no
>> > pages.
>> > 
>>> >> +		mutex_unlock(&zonelists_mutex);
>>> >> +	} else
>>> >> +		zone_pcp_update(zone);
>> > 
>> > There is more than one zone in a node. So the zone can have
>> > no pages when the node has some pages.
>> > 
> Yes, you are right. Here is the new patch,

This version looks fine to me.

> 
> Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
> ---
>  mm/memory_hotplug.c |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index bc7e7a2..5f6997f 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -973,8 +973,13 @@ repeat:
> 
>  	init_per_zone_wmark_min();
> 
> -	if (!populated_zone(zone))
> +	if (!populated_zone(zone)) {
>  		zone_pcp_reset(zone);
> +		mutex_lock(&zonelists_mutex);
> +		build_all_zonelists(NULL, NULL);
> +		mutex_unlock(&zonelists_mutex);
> +	} else
> +		zone_pcp_update(zone);
> 
>  	if (!node_present_pages(node)) {
>  		node_clear_state(node, N_HIGH_MEMORY);
> -- 1.7.6.1
>> > And we have called drain_all_pages(), I think there is no need
>> > to call zone_pcp_update() here.
>> > 
>> > Thanks
>> > Wen Congyang
>> > 
> In zone_pcp_update(), it calculates zone_batchsize() which does
> not calculated in drain_all_pages().

Yes, zone_batchsize() depends on zone's present pages.
If zone's present pages are changed, zone's pcp should be updated.

Thanks
Wen Congyang

> 
> Thanks
> Xishi Qiu
> 
>>> >>
>>> >>  	vm_total_pages = nr_free_pagecache_pages();
>>> >>  	writeback_set_ratelimit();
>> > 
>> > 
> --
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