From: Miaohe Lin <linmiaohe@huawei.com>
To: David Hildenbrand <david@redhat.com>, <akpm@linux-foundation.org>
Cc: <vbabka@suse.cz>, <iamjoonsoo.kim@lge.com>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/page_isolation: don't putback unisolated page
Date: Mon, 6 Sep 2021 19:32:30 +0800 [thread overview]
Message-ID: <b533742e-e82a-a721-9a24-4087688dd812@huawei.com> (raw)
In-Reply-To: <e060283a-6295-9191-9b92-a3c183e9de02@redhat.com>
On 2021/9/6 17:40, David Hildenbrand wrote:
> On 04.09.21 11:18, Miaohe Lin wrote:
>> If __isolate_free_page() failed, due to zone watermark check, the page is
>> still on the free list. But this page will be put back to free list again
>> via __putback_isolated_page() now. This may trigger page->flags checks in
>> __free_one_page() if PageReported is set. Or we will corrupt the free list
>> because list_add() will be called for pages already on another list.
>>
>> Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>> mm/page_isolation.c | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
>> index 9bb562d5d194..7d70d772525c 100644
>> --- a/mm/page_isolation.c
>> +++ b/mm/page_isolation.c
>> @@ -93,10 +93,8 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
>> buddy_pfn = __find_buddy_pfn(pfn, order);
>> buddy = page + (buddy_pfn - pfn);
>> - if (!is_migrate_isolate_page(buddy)) {
>> - __isolate_free_page(page, order);
>> - isolated_page = true;
>> - }
>> + if (!is_migrate_isolate_page(buddy))
>> + isolated_page = !!__isolate_free_page(page, order);
>> }
>> }
>>
>
> Shouldn't we much rather force to ignore watermarks here and make sure __isolate_free_page() never fails?
It seems it is not easy to force to ignore watermarks here. And it's not a problem
if __isolate_free_page() fails because we can do move_freepages_block() anyway.
What do you think? Many thanks.
>
next prev parent reply other threads:[~2021-09-06 11:32 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-04 9:18 [PATCH] mm/page_isolation: don't putback unisolated page Miaohe Lin
2021-09-06 9:40 ` David Hildenbrand
2021-09-06 11:32 ` Miaohe Lin [this message]
2021-09-06 11:50 ` David Hildenbrand
2021-09-06 12:01 ` David Hildenbrand
2021-09-06 12:08 ` Miaohe Lin
2021-09-06 12:02 ` David Hildenbrand
2021-09-06 12:11 ` David Hildenbrand
2021-09-06 12:45 ` Miaohe Lin
2021-09-06 12:49 ` David Hildenbrand
2021-09-07 1:46 ` Miaohe Lin
2021-09-07 9:52 ` David Hildenbrand
2021-09-07 8:08 ` Vlastimil Babka
2021-09-07 9:56 ` David Hildenbrand
2021-09-08 22:42 ` John Hubbard
2021-09-09 8:56 ` David Hildenbrand
2021-09-09 9:07 ` Vlastimil Babka
2021-09-09 9:37 ` David Hildenbrand
2021-09-09 16:50 ` John Hubbard
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