From: Mel Gorman <mgorman@suse.de>
To: Chen Gang <gang.chen@asianux.com>
Cc: hannes@cmpxchg.org, riel@redhat.com, mhocko@suse.cz,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/vmscan.c: 'lru' may be used without initialized after the patch "3abf380..." in next-20130607 tree
Date: Wed, 19 Jun 2013 09:53:16 +0100 [thread overview]
Message-ID: <20130619085315.GK1875@suse.de> (raw)
In-Reply-To: <51C155D1.3090304@asianux.com>
On Wed, Jun 19, 2013 at 02:55:13PM +0800, Chen Gang wrote:
>
> 'lru' may be used without initialized, so need regressing part of the
> related patch.
>
> The related patch:
> "3abf380 mm: remove lru parameter from __lru_cache_add and lru_cache_add_lru"
>
>
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
> mm/vmscan.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index fe73724..e92b1858 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -595,6 +595,7 @@ redo:
> * unevictable page on [in]active list.
> * We know how to handle that.
> */
> + lru = !!TestClearPageActive(page) + page_lru_base_type(page);
> lru_cache_add(page);
Thanks for catching this but I have one question. Why are you clearing
the active bit?
Before 3abf380 we did
active = TestClearPageActive(page);
lru = active + page_lru_base_type(page);
lru_cache_add_lru(page, lru);
so if the page was active before then it gets added to the active list. When
3abf380 is applied. it becomes.
Leave PageActive alone
lru_cache_add(page);
..... until __pagevec_lru_add -> __pagevec_lru_add_fn
int file = page_is_file_cache(page);
int active = PageActive(page);
enum lru_list lru = page_lru(page);
After your patch it's
Clear PageActive
lru_cache_add(page)
.......
always add to inactive list
I do not think you intended to do this and if you did, it deserves far
more comment than being a compile warning fix. In putback_lru_page we only
care about whether the lru was unevictable or not. Hence I think what you
meant to do was simply
lru = page_lru_base_type(page);
If you agree then can you resend a revised version to Andrew please?
--
Mel Gorman
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Chen Gang <gang.chen@asianux.com>
Cc: hannes@cmpxchg.org, riel@redhat.com, mhocko@suse.cz,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/vmscan.c: 'lru' may be used without initialized after the patch "3abf380..." in next-20130607 tree
Date: Wed, 19 Jun 2013 09:53:16 +0100 [thread overview]
Message-ID: <20130619085315.GK1875@suse.de> (raw)
In-Reply-To: <51C155D1.3090304@asianux.com>
On Wed, Jun 19, 2013 at 02:55:13PM +0800, Chen Gang wrote:
>
> 'lru' may be used without initialized, so need regressing part of the
> related patch.
>
> The related patch:
> "3abf380 mm: remove lru parameter from __lru_cache_add and lru_cache_add_lru"
>
>
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
> mm/vmscan.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index fe73724..e92b1858 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -595,6 +595,7 @@ redo:
> * unevictable page on [in]active list.
> * We know how to handle that.
> */
> + lru = !!TestClearPageActive(page) + page_lru_base_type(page);
> lru_cache_add(page);
Thanks for catching this but I have one question. Why are you clearing
the active bit?
Before 3abf380 we did
active = TestClearPageActive(page);
lru = active + page_lru_base_type(page);
lru_cache_add_lru(page, lru);
so if the page was active before then it gets added to the active list. When
3abf380 is applied. it becomes.
Leave PageActive alone
lru_cache_add(page);
..... until __pagevec_lru_add -> __pagevec_lru_add_fn
int file = page_is_file_cache(page);
int active = PageActive(page);
enum lru_list lru = page_lru(page);
After your patch it's
Clear PageActive
lru_cache_add(page)
.......
always add to inactive list
I do not think you intended to do this and if you did, it deserves far
more comment than being a compile warning fix. In putback_lru_page we only
care about whether the lru was unevictable or not. Hence I think what you
meant to do was simply
lru = page_lru_base_type(page);
If you agree then can you resend a revised version to Andrew please?
--
Mel Gorman
SUSE Labs
--
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next prev parent reply other threads:[~2013-06-19 8:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 6:55 [PATCH] mm/vmscan.c: 'lru' may be used without initialized after the patch "3abf380..." in next-20130607 tree Chen Gang
2013-06-19 6:55 ` Chen Gang
2013-06-19 7:10 ` Andrew Morton
2013-06-19 7:10 ` Andrew Morton
2013-06-19 7:19 ` Chen Gang
2013-06-19 7:19 ` Chen Gang
2013-07-05 4:06 ` Chen Gang
2013-07-05 4:06 ` Chen Gang
2013-07-08 6:43 ` Chen Gang
2013-07-08 6:43 ` Chen Gang
2013-07-09 2:16 ` Chen Gang
2013-07-09 2:16 ` Chen Gang
2013-06-19 8:53 ` Mel Gorman [this message]
2013-06-19 8:53 ` Mel Gorman
2013-06-19 9:56 ` Chen Gang
2013-06-19 9:56 ` Chen Gang
2013-06-19 10:25 ` [PATCH v2] " Chen Gang
2013-06-19 10:25 ` Chen Gang
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