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Date:   Tue, 17 Oct 2023 11:26:36 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Alexandru Elisei <alexandru.elisei@arm.com>
Cc:     Hyesoo Yu <hyesoo.yu@samsung.com>, will@kernel.org,
        oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com,
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Subject: Re: [PATCH RFC 06/37] mm: page_alloc: Allocate from movable pcp
 lists only if ALLOC_FROM_METADATA
Message-ID: <ZS5hXFHs08zQOboi@arm.com>
References: <20230823131350.114942-1-alexandru.elisei@arm.com>
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 <CGME20231012013524epcas2p4b50f306e3e4d0b937b31f978022844e5@epcas2p4.samsung.com>
 <20231010074823.GA2536665@tiffany>
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On Mon, Oct 16, 2023 at 01:41:15PM +0100, Alexandru Elisei wrote:
> On Thu, Oct 12, 2023 at 10:25:11AM +0900, Hyesoo Yu wrote:
> > I don't think it would be effcient when the majority of movable pages
> > do not use GFP_TAGGED.
> > 
> > Metadata pages have a low probability of being in the pcp list
> > because metadata pages is bypassed when freeing pages.
> > 
> > The allocation performance of most movable pages is likely to decrease
> > if only the request with ALLOC_FROM_METADATA could be allocated.
> 
> You're right, I hadn't considered that.
> 
> > 
> > How about not including metadata pages in the pcp list at all ?
> 
> Sounds reasonable, I will keep it in mind for the next iteration of the
> series.

BTW, I suggest for the next iteration we drop MIGRATE_METADATA, only use
CMA and assume that the tag storage itself supports tagging. Hopefully
it makes the patches a bit simpler.

-- 
Catalin