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* [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning
@ 2013-09-06  5:16 Weijie Yang
  2013-09-06  6:31 ` Bob Liu
  2013-09-09 16:29 ` Seth Jennings
  0 siblings, 2 replies; 5+ messages in thread
From: Weijie Yang @ 2013-09-06  5:16 UTC (permalink / raw)
  To: sjenning; +Cc: minchan, bob.liu, weijie.yang.kh, linux-mm, linux-kernel

add SetPageReclaim before __swap_writepage so that page can be moved to the
tail of the inactive list, which can avoid unnecessary page scanning as this
page was reclaimed by swap subsystem before.

Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
---
 mm/zswap.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/zswap.c b/mm/zswap.c
index 1be7b90..cc40e6a 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -556,6 +556,9 @@ static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
 		SetPageUptodate(page);
 	}
 
+	/* move it to the tail of the inactive list after end_writeback */
+	SetPageReclaim(page);
+
 	/* start writeback */
 	__swap_writepage(page, &wbc, end_swap_bio_write);
 	page_cache_release(page);
-- 
1.7.10.4


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^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning
  2013-09-06  5:16 [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning Weijie Yang
@ 2013-09-06  6:31 ` Bob Liu
  2013-09-09 16:29 ` Seth Jennings
  1 sibling, 0 replies; 5+ messages in thread
From: Bob Liu @ 2013-09-06  6:31 UTC (permalink / raw)
  To: Weijie Yang; +Cc: sjenning, minchan, weijie.yang.kh, linux-mm, linux-kernel


On 09/06/2013 01:16 PM, Weijie Yang wrote:
> add SetPageReclaim before __swap_writepage so that page can be moved to the
> tail of the inactive list, which can avoid unnecessary page scanning as this
> page was reclaimed by swap subsystem before.
> 
> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>

Reviewed-by: Bob Liu <bob.liu@oracle.com>

> ---
>  mm/zswap.c |    3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/zswap.c b/mm/zswap.c
> index 1be7b90..cc40e6a 100644
> --- a/mm/zswap.c
> +++ b/mm/zswap.c
> @@ -556,6 +556,9 @@ static int zswap_writeback_entry(struct zbud_pool *pool, unsigned long handle)
>  		SetPageUptodate(page);
>  	}
>  
> +	/* move it to the tail of the inactive list after end_writeback */
> +	SetPageReclaim(page);
> +
>  	/* start writeback */
>  	__swap_writepage(page, &wbc, end_swap_bio_write);
>  	page_cache_release(page);
> 

-- 
Regards,
-Bob

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning
  2013-09-06  5:16 [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning Weijie Yang
  2013-09-06  6:31 ` Bob Liu
@ 2013-09-09 16:29 ` Seth Jennings
  2013-09-23  2:06   ` Bob Liu
  1 sibling, 1 reply; 5+ messages in thread
From: Seth Jennings @ 2013-09-09 16:29 UTC (permalink / raw)
  To: Weijie Yang; +Cc: minchan, bob.liu, weijie.yang.kh, linux-mm, linux-kernel

On Fri, Sep 06, 2013 at 01:16:45PM +0800, Weijie Yang wrote:
> add SetPageReclaim before __swap_writepage so that page can be moved to the
> tail of the inactive list, which can avoid unnecessary page scanning as this
> page was reclaimed by swap subsystem before.
> 
> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>

Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning
  2013-09-09 16:29 ` Seth Jennings
@ 2013-09-23  2:06   ` Bob Liu
  2013-09-23  6:07     ` Weijie Yang
  0 siblings, 1 reply; 5+ messages in thread
From: Bob Liu @ 2013-09-23  2:06 UTC (permalink / raw)
  To: Seth Jennings
  Cc: Weijie Yang, minchan, weijie.yang.kh, linux-mm, linux-kernel


On 09/10/2013 12:29 AM, Seth Jennings wrote:
> On Fri, Sep 06, 2013 at 01:16:45PM +0800, Weijie Yang wrote:
>> add SetPageReclaim before __swap_writepage so that page can be moved to the
>> tail of the inactive list, which can avoid unnecessary page scanning as this
>> page was reclaimed by swap subsystem before.
>>
>> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
> 
> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
> 

Below is a reply from Mel in original thread "[PATCHv11 3/4] zswap: add
to mm/"
------------------
> +     /* start writeback */
> +     SetPageReclaim(page);
> +     __swap_writepage(page, &wbc, end_swap_bio_write);
> +     page_cache_release(page);
> +     zswap_written_back_pages++;
> +

SetPageReclaim? Why?. If the page is under writeback then why do you not
mark it as that? Do not free pages that are currently under writeback
obviously. It's likely that it was PageWriteback you wanted in zbud.c too.
--------------------

-- 
Regards,
-Bob

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^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning
  2013-09-23  2:06   ` Bob Liu
@ 2013-09-23  6:07     ` Weijie Yang
  0 siblings, 0 replies; 5+ messages in thread
From: Weijie Yang @ 2013-09-23  6:07 UTC (permalink / raw)
  To: Bob Liu; +Cc: Seth Jennings, Weijie Yang, minchan, linux-mm, linux-kernel

On Mon, Sep 23, 2013 at 10:06 AM, Bob Liu <bob.liu@oracle.com> wrote:
>
> On 09/10/2013 12:29 AM, Seth Jennings wrote:
>> On Fri, Sep 06, 2013 at 01:16:45PM +0800, Weijie Yang wrote:
>>> add SetPageReclaim before __swap_writepage so that page can be moved to the
>>> tail of the inactive list, which can avoid unnecessary page scanning as this
>>> page was reclaimed by swap subsystem before.
>>>
>>> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
>>
>> Acked-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
>>
>
> Below is a reply from Mel in original thread "[PATCHv11 3/4] zswap: add
> to mm/"
> ------------------
>> +     /* start writeback */
>> +     SetPageReclaim(page);
>> +     __swap_writepage(page, &wbc, end_swap_bio_write);
>> +     page_cache_release(page);
>> +     zswap_written_back_pages++;
>> +
>
> SetPageReclaim? Why?. If the page is under writeback then why do you not
> mark it as that? Do not free pages that are currently under writeback
> obviously. It's likely that it was PageWriteback you wanted in zbud.c too.
> --------------------

Thanks for reminding this.

The purpose of using this flag in PATCHv11 and this patch is different.

In PATCHv11, it was repurposed to protect zbud page against free,
and now it is replaced with zhdr->under_reclaim.

In this patch, this flag is for its original purpose(to be reclaimed asap)

> --
> Regards,
> -Bob

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^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2013-09-23  6:08 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2013-09-06  5:16 [PATCH v2 3/4] mm/zswap: avoid unnecessary page scanning Weijie Yang
2013-09-06  6:31 ` Bob Liu
2013-09-09 16:29 ` Seth Jennings
2013-09-23  2:06   ` Bob Liu
2013-09-23  6:07     ` Weijie Yang

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