linux-kernel - Re: [PATCH v4] arm64/mm: Optimize loop to reduce redundant operations of contpte_ptep

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Message-ID: <9ada79ec-f2b4-42bc-84f9-3f7b461ad829@redhat.com>
Date: Thu, 8 May 2025 10:30:14 +0200
From: David Hildenbrand <david@...hat.com>
To: Xavier Xia <xavier_qy@....com>, 21cnbao@...il.com, ryan.roberts@....com,
 dev.jain@....com, ioworker0@...il.com
Cc: akpm@...ux-foundation.org, catalin.marinas@....com, gshan@...hat.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 will@...nel.org, willy@...radead.org, ziy@...dia.com
Subject: Re: [PATCH v4] arm64/mm: Optimize loop to reduce redundant operations
 of contpte_ptep_get

On 08.05.25 09:03, Xavier Xia wrote:
> This commit optimizes the contpte_ptep_get and contpte_ptep_get_lockless
> function by adding early termination logic. It checks if the dirty and
> young bits of orig_pte are already set and skips redundant bit-setting
> operations during the loop. This reduces unnecessary iterations and
> improves performance.
> 
> In order to verify the optimization performance, a test function has been
> designed. The function's execution time and instruction statistics have
> been traced using perf, and the following are the operation results on a
> certain Qualcomm mobile phone chip:

For the future, please don't post vN+1 as reply to vN.

-- 
Cheers,

David / dhildenb