From: David Hildenbrand <david@redhat.com>
To: Lance Yang <lance.yang@linux.dev>,
akpm@linux-foundation.org, lorenzo.stoakes@oracle.com
Cc: ziy@nvidia.com, baolin.wang@linux.alibaba.com,
Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com,
dev.jain@arm.com, baohua@kernel.org, ioworker0@gmail.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Kairui Song <kasong@tencent.com>
Subject: Re: [PATCH mm-new 2/3] mm: clean up and expose is_guard_pte_marker()
Date: Wed, 17 Sep 2025 12:32:22 +0200 [thread overview]
Message-ID: <ee7e0841-e9b6-4a91-8b6c-43252432516c@redhat.com> (raw)
In-Reply-To: <20250914143547.27687-3-lance.yang@linux.dev>
On 14.09.25 16:35, Lance Yang wrote:
> From: Lance Yang <lance.yang@linux.dev>
>
> is_guard_pte_marker() performs a redundant check because it calls both
> is_pte_marker() and is_guard_swp_entry(), both of which internally check
> for a PTE marker.
>
> is_guard_pte_marker()
> |- is_pte_marker()
> | `- is_pte_marker_entry() // First check
> `- is_guard_swp_entry()
> `- is_pte_marker_entry() // Second, redundant check
>
> While a modern compiler could likely optimize this away, let's have clean
> code and not rely on it ;)
>
> Also, make it available for hugepage collapsing code.
>
> Cc: Kairui Song <kasong@tencent.com>
> Signed-off-by: Lance Yang <lance.yang@linux.dev>
> ---
Acked-by: David Hildenbrand <david@redhat.com>
--
Cheers
David / dhildenb
next prev parent reply other threads:[~2025-09-17 10:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-14 14:35 [PATCH mm-new 0/3] mm/khugepaged: optimize collapse candidate detection Lance Yang
2025-09-14 14:35 ` [PATCH mm-new 1/3] mm/khugepaged: skip unsuitable VMAs earlier in khugepaged_scan_mm_slot() Lance Yang
2025-09-14 16:16 ` Dev Jain
2025-09-15 3:02 ` Lance Yang
2025-09-16 5:32 ` Hugh Dickins
2025-09-16 6:21 ` Lance Yang
2025-09-16 6:42 ` Hugh Dickins
2025-09-16 7:05 ` Lance Yang
2025-09-16 9:29 ` Kiryl Shutsemau
2025-09-16 9:39 ` Lorenzo Stoakes
2025-09-16 9:48 ` Kiryl Shutsemau
2025-09-16 9:58 ` Lorenzo Stoakes
2025-09-16 10:00 ` Lance Yang
2025-09-16 9:59 ` Lance Yang
2025-09-14 14:35 ` [PATCH mm-new 2/3] mm: clean up and expose is_guard_pte_marker() Lance Yang
2025-09-14 16:38 ` Dev Jain
2025-09-15 4:24 ` Lance Yang
2025-09-15 13:54 ` Lorenzo Stoakes
2025-09-15 14:26 ` Lance Yang
2025-09-17 10:32 ` David Hildenbrand [this message]
2025-09-14 14:35 ` [PATCH mm-new 3/3] mm/khugepaged: abort collapse scan on guard PTEs Lance Yang
2025-09-14 17:03 ` Dev Jain
2025-09-15 3:36 ` Lance Yang
2025-09-15 14:08 ` Lorenzo Stoakes
2025-09-15 14:42 ` Lance Yang
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