From: Mike Kravetz <mike.kravetz@oracle.com>
To: Baolin Wang <baolin.wang@linux.alibaba.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Muchun Song <songmuchun@bytedance.com>,
Michal Hocko <mhocko@suse.com>, Peter Xu <peterx@redhat.com>,
Naoya Horiguchi <naoya.horiguchi@linux.dev>,
James Houghton <jthoughton@google.com>,
Mina Almasry <almasrymina@google.com>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH 1/3] hugetlb: skip to end of PT page mapping when pte not present
Date: Tue, 31 May 2022 09:56:52 -0700 [thread overview]
Message-ID: <3029924e-0857-3684-52ea-f37e924ceb4a@oracle.com> (raw)
In-Reply-To: <437e45c5-c46a-46f4-f9cf-d8c2397c988d@linux.alibaba.com>
On 5/30/22 03:10, Baolin Wang wrote:
> On 5/28/2022 6:58 AM, Mike Kravetz wrote:
>
> I tested on my ARM64 machine with implementing arm64 specific hugetlb_mask_last_hp() as below, and it works well.
>
> Just a few nits inline, otherwise looks good to me.
> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
>
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index d93ba128a2b0..e04a097ffcc4 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -376,6 +376,28 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
> return NULL;
> }
>
> +unsigned long hugetlb_mask_last_hp(struct hstate *h)
> +{
> + unsigned long hp_size = huge_page_size(h);
> +
> + switch (hp_size) {
> + case P4D_SIZE:
> + return PGDIR_SIZE - P4D_SIZE;
> + case PUD_SIZE:
> + return P4D_SIZE - PUD_SIZE;
> + case CONT_PMD_SIZE:
> + return PUD_SIZE - CONT_PMD_SIZE;
> + case PMD_SIZE:
> + return PUD_SIZE - PMD_SIZE;
> + case CONT_PTE_SIZE:
> + return PMD_SIZE - CONT_PTE_SIZE;
> + default:
> + break;
> + }
> +
> + return ~(0UL);
> +}
>
Thanks! I was hesitant to put something together for those CONT_* sizes.
>> +/*
>> + * Return a mask that can be used to update an address to the last huge
>> + * page in a page table page mapping size. Used to skip non-present
>> + * page table entries when linearly scanning address ranges. Architectures
>> + * with unique huge page to page table relationships can define their own
>> + * version of this routine.
>> + */
>> +unsigned long hugetlb_mask_last_hp(struct hstate *h)
>> +{
>> + unsigned long hp_size = huge_page_size(h);
>> +
>> + if (hp_size == P4D_SIZE)
>> + return PGDIR_SIZE - P4D_SIZE;
>> + else if (hp_size == PUD_SIZE)
>> + return P4D_SIZE - PUD_SIZE;
>> + else if (hp_size == PMD_SIZE)
>> + return PUD_SIZE - PMD_SIZE;
>
> Changing to use 'switch' looks more readable?
Agree. Or, I might just go with Peter's simplification.
>
>> +
>> + return ~(0);
>
> Better to return '~(0UL)' to keep function type consistent.
Yes, thanks!
--
Mike Kravetz
next prev parent reply other threads:[~2022-05-31 16:57 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-27 22:58 [RFC PATCH 0/3] hugetlb: speed up linear address scanning Mike Kravetz
2022-05-27 22:58 ` [RFC PATCH 1/3] hugetlb: skip to end of PT page mapping when pte not present Mike Kravetz
2022-05-30 10:10 ` Baolin Wang
2022-05-31 16:56 ` Mike Kravetz [this message]
2022-06-15 21:22 ` Mike Kravetz
2022-06-16 3:48 ` Baolin Wang
2022-05-30 19:56 ` Peter Xu
2022-05-31 2:04 ` Muchun Song
2022-05-31 17:05 ` Mike Kravetz
2022-06-01 6:58 ` Anshuman Khandual
2022-05-31 17:00 ` Mike Kravetz
2022-06-15 17:27 ` Mike Kravetz
2022-06-15 17:51 ` Peter Xu
2022-05-27 22:58 ` [RFC PATCH 2/3] hugetlb: do not update address in huge_pmd_unshare Mike Kravetz
2022-05-30 10:14 ` Baolin Wang
2022-05-30 15:36 ` Muchun Song
2022-05-31 17:06 ` Mike Kravetz
2022-05-27 22:58 ` [RFC PATCH 3/3] hugetlb: Lazy page table copies in fork() Mike Kravetz
2022-05-31 17:25 ` David Hildenbrand
2022-06-01 5:20 ` Muchun Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3029924e-0857-3684-52ea-f37e924ceb4a@oracle.com \
--to=mike.kravetz@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=almasrymina@google.com \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=anshuman.khandual@arm.com \
--cc=baolin.wang@linux.alibaba.com \
--cc=borntraeger@linux.ibm.com \
--cc=jthoughton@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=naoya.horiguchi@linux.dev \
--cc=paul.walmsley@sifive.com \
--cc=peterx@redhat.com \
--cc=songmuchun@bytedance.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).