From: Vlastimil Babka <vbabka@suse.cz>
To: Zi Yan <ziy@nvidia.com>, David Hildenbrand <david@redhat.com>
Cc: linux-mm@kvack.org, Alexander Potapenko <glider@google.com>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Miaohe Lin <linmiaohe@huawei.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
John Hubbard <jhubbard@nvidia.com>,
"Huang, Ying" <ying.huang@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] mm: avoid clearing user movable page twice with init_on_alloc=1
Date: Tue, 8 Oct 2024 14:57:48 +0200 [thread overview]
Message-ID: <be1a1c1b-4630-41e2-a79a-57447851017d@suse.cz> (raw)
In-Reply-To: <84D24C40-AC10-4FF7-B5F6-63FADD523297@nvidia.com>
On 10/8/24 13:52, Zi Yan wrote:
> On 8 Oct 2024, at 4:26, David Hildenbrand wrote:
>
>>
>> I remember we discussed that in the past and that we do *not* want to sprinkle these CONFIG_INIT_ON_ALLOC_DEFAULT_ON checks all over the kernel.
>>
>> Ideally, we'd use GFP_ZERO and have the buddy just do that for us? There is the slight chance that we zero-out when we're not going to use the allocated folio, but ... that can happen either way even with the current code?
>
> I agree that putting CONFIG_INIT_ON_ALLOC_DEFAULT_ON here is not ideal, but
Create some nice inline wrapper for the test and it will look less ugly? :)
> folio_zero_user() uses vmf->address to improve cache performance by changing
> subpage clearing order. See commit c79b57e462b5 ("mm: hugetlb: clear target
> sub-page last when clearing huge page”). If we use GFP_ZERO, we lose this
> optimization. To keep it, vmf->address will need to be passed to allocation
> code. Maybe that is acceptable?
I'd rather not change the page allocation code for this...
> Best Regards,
> Yan, Zi
next prev parent reply other threads:[~2024-10-08 12:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-07 18:23 Zi Yan
2024-10-08 8:26 ` David Hildenbrand
2024-10-08 11:52 ` Zi Yan
2024-10-08 12:57 ` Vlastimil Babka [this message]
2024-10-08 13:06 ` David Hildenbrand
2024-10-08 13:46 ` Zi Yan
2024-10-11 6:55 ` Huang, Ying
2024-10-11 6:57 ` Huang, Ying
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