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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.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>,
	linux-mm@kvack.org,  linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: remove unnecessary page_table_lock on stack expansion
Date: Fri, 1 Nov 2024 08:59:58 -1000	[thread overview]
Message-ID: <CAHk-=whhiQtzQ4L80rQg7uQzM1cPcNh9nE9U=Bn=iSVaYXPi2g@mail.gmail.com> (raw)
In-Reply-To: <20241101184627.131391-1-lorenzo.stoakes@oracle.com>

On Fri, 1 Nov 2024 at 08:46, Lorenzo Stoakes <lorenzo.stoakes@oracle.com> wrote:
>
> Each of which acquire the mmap write lock before doing so. Despite this, we
> maintain code that acquires a page table lock in the expand_upwards() and
> expand_downwards() code, stating that we hold a shared mmap lock and thus
> this is necessary.
>
> It is not, we do not have to worry about concurrent VMA expansions so we
> can simply drop this, and update comments accordingly.
>
> We do not even need be concerned with racing page faults, as
> vma_start_write() is invoked in both cases.

Ack, seems ObviouslyCorrect(tm).

           Linus


  reply	other threads:[~2024-11-01 19:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-11-01 18:46 Lorenzo Stoakes
2024-11-01 18:59 ` Linus Torvalds [this message]
2024-11-01 20:34 ` Jann Horn
2024-11-05  9:17 ` Vlastimil Babka
2024-11-05 15:07 ` Liam R. Howlett

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