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From: David Hildenbrand <david@redhat.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	Barry Song <21cnbao@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
	Pedro Falcato <pfalcato@suse.de>, Dev Jain <dev.jain@arm.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH HOTFIX 6.17] mm/mremap: avoid expensive folio lookup on mremap folio pte batch
Date: Mon, 11 Aug 2025 17:19:26 +0200	[thread overview]
Message-ID: <dbd8c326-8848-486f-8789-3528dea2bb28@redhat.com> (raw)
In-Reply-To: <0babf2ec-040f-4f7b-aa76-f59e80274333@lucifer.local>


>>
>> Unless the previous contpte_try_unfold() was very costly and removing it yielded
>> a significant improvement, it’s difficult to see how the benefits would outweigh
>> the drawbacks of vm_normal_folio(). Does this imply that there was already a
>> regression in mremap() caused by contpte_try_unfold() before?
>> And that Dev’s patch is essentially a fix for this regression on arm64?

Fix/regression might be the wrong words here IMHO, but yes, this code 
was not playing nicely with automatic cont-pte folding/unfolding , and 
now it's optimized for that.

-- 
Cheers,

David / dhildenb


      reply	other threads:[~2025-08-11 15:19 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-08-07 18:58 Lorenzo Stoakes
2025-08-07 19:10 ` David Hildenbrand
2025-08-07 19:20   ` Lorenzo Stoakes
2025-08-07 19:41     ` David Hildenbrand
2025-08-07 20:11       ` Lorenzo Stoakes
2025-08-07 21:01         ` Lorenzo Stoakes
2025-08-07 19:56     ` Ryan Roberts
2025-08-07 20:58       ` Lorenzo Stoakes
2025-08-08  5:18         ` Dev Jain
2025-08-08  7:19         ` Ryan Roberts
2025-08-08  7:45           ` David Hildenbrand
2025-08-08  7:56             ` Ryan Roberts
2025-08-08  8:44               ` Dev Jain
2025-08-08  9:50                 ` Lorenzo Stoakes
2025-08-08  9:45             ` Lorenzo Stoakes
2025-08-08  9:40           ` Lorenzo Stoakes
2025-08-07 19:14 ` Pedro Falcato
2025-08-07 19:22   ` Lorenzo Stoakes
2025-08-07 19:33     ` David Hildenbrand
2025-08-08  5:19 ` Dev Jain
2025-08-08  9:56 ` Vlastimil Babka
2025-08-11  2:40 ` Barry Song
2025-08-11  4:57   ` Lorenzo Stoakes
2025-08-11  6:52     ` Barry Song
2025-08-11 15:08       ` Lorenzo Stoakes
2025-08-11 15:19         ` David Hildenbrand [this message]

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