From: Oscar Salvador <osalvador@suse.de>
To: Muchun Song <songmuchun@bytedance.com>
Cc: akpm@linux-foundation.org, vbabka@suse.cz, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm/page_alloc: speeding up the iteration of max_order
Date: Mon, 7 Dec 2020 14:37:42 +0100 [thread overview]
Message-ID: <20201207133735.GA12191@linux> (raw)
In-Reply-To: <20201204155109.55451-1-songmuchun@bytedance.com>
On Fri, Dec 04, 2020 at 11:51:09PM +0800, Muchun Song wrote:
> When we free a page whose order is very close to MAX_ORDER and greater
> than pageblock_order, it wastes some CPU cycles to increase max_order
> to MAX_ORDER one by one and check the pageblock migratetype of that page
> repeatedly especially when MAX_ORDER is much larger than pageblock_order.
>
> We also should not be checking migratetype of buddy when "order ==
> MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition.
> With the new check, we don't need the max_order check anymore, so we
> replace it.
>
> Also adjust max_order initialization so that it's lower by one than
> previously, which makes the code hopefully more clear.
>
> Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
--
Oscar Salvador
SUSE L3
prev parent reply other threads:[~2020-12-07 13:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 15:51 [PATCH v3] mm/page_alloc: speeding up the iteration of max_order Muchun Song
2020-12-07 9:44 ` David Hildenbrand
2020-12-07 13:37 ` Oscar Salvador [this message]
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