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Fri, 03 Oct 2025 06:21:19 -0700 (PDT) Date: Fri, 3 Oct 2025 13:21:18 +0000 From: Wei Yang To: Lance Yang Cc: akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, 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, richard.weiyang@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH mm-new 1/2] mm/khugepaged: optimize PTE scanning with if-else-if-else-if chain Message-ID: <20251003132118.qe2wipbrzwkbaatq@master> Reply-To: Wei Yang References: <20251002073255.14867-1-lance.yang@linux.dev> <20251002073255.14867-2-lance.yang@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251002073255.14867-2-lance.yang@linux.dev> User-Agent: NeoMutt/20170113 (1.7.2) On Thu, Oct 02, 2025 at 03:32:54PM +0800, Lance Yang wrote: >From: Lance Yang > >As pointed out by Dev, the PTE checks for disjoint conditions in the >scanning loops can be optimized. is_swap_pte, (pte_none && is_zero_pfn), >and pte_uffd_wp are mutually exclusive. > >This patch refactors the loops in both __collapse_huge_page_isolate() and >hpage_collapse_scan_pmd() to use a continuous if-else-if-else-if chain >instead of separate if blocks. > >Also, this is a preparatory step to make it easier to merge the >almost-duplicated scanning logic in these two functions, as suggested >by David. > >Suggested-by: Dev Jain >Suggested-by: David Hildenbrand >Signed-off-by: Lance Yang Reviewed-by: Wei Yang -- Wei Yang Help you, Help me