Re: Re: [External] Re: vmscan: Reclaim unevictable pages

From: Pankaj Suryawanshi
Date: Thu Mar 14 2019 - 09:44:52 EST



Hello ,

Please ignore the curly braces, they are just for debugging.

Below is the updated patch.


diff --git a/mm/vmscan.c b/mm/vmscan.c
index be56e2e..12ac353 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -998,7 +998,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
sc->nr_scanned++;

if (unlikely(!page_evictable(page)))
- goto activate_locked;
+ goto cull_mlocked;

if (!sc->may_unmap && page_mapped(page))
goto keep_locked;
@@ -1331,7 +1331,12 @@ static unsigned long shrink_page_list(struct list_head *page_list,
} else
list_add(&page->lru, &free_pages);
continue;
-
+cull_mlocked:
+ if (PageSwapCache(page))
+ try_to_free_swap(page);
+ unlock_page(page);
+ list_add(&page->lru, &ret_pages);
+ continue;
activate_locked:
/* Not a candidate for swapping, so reclaim swap space. */
if (PageSwapCache(page) && (mem_cgroup_swap_full(page) ||



Regards,
Pankaj


From: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Sent: 14 March 2019 14:55:34
To: Pankaj Suryawanshi; Michal Hocko
Cc: linux-kernel@xxxxxxxxxxxxxxx; minchan@xxxxxxxxxx
Subject: Re: Re: [External] Re: vmscan: Reclaim unevictable pages


On 14.03.2019 11:52, Pankaj Suryawanshi wrote:
>
> I am using kernel version 4.14.65 (on Android pie [ARM]).
>
> No additional patches applied on top of vanilla.(Core MM).
>
> If I change in the vmscan.c as below patch, it will work.

Sorry, but 4.14.65 does not have braces around trylock_page(),
like in your patch below.

See https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/mm/vmscan.c?h=v4.14.65

[...]

>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index be56e2e..2e51edc 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -990,15 +990,17 @@ static unsigned long shrink_page_list(struct list_head *page_list,
>> page = lru_to_page(page_list);
>> list_del(&page->lru);
>>
>> if (!trylock_page(page)) {
>> goto keep;
>> }

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