From: Matthew Wilcox <willy@infradead.org>
To: Waiman Long <llong@redhat.com>
Cc: lizhe.67@bytedance.com, peterz@infradead.org, mingo@redhat.com,
will@kernel.org, boqun.feng@gmail.com, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC 1/2] rwsem: introduce upgrade_read interface
Date: Wed, 16 Oct 2024 19:05:54 +0100 [thread overview]
Message-ID: <ZxAAgikXWswSJ76D@casper.infradead.org> (raw)
In-Reply-To: <7f7b277a-7019-4bf4-b100-0505c6ce9737@redhat.com>
On Wed, Oct 16, 2024 at 10:23:14AM -0400, Waiman Long wrote:
> Another alternative that I have been thinking about is a down_read() variant
> with intention to upgrade later. This will ensure that only one active
> reader is allowed to upgrade later. With this, upgrade_read() will always
> succeed, maybe with some sleeping, as long as the correct down_read() is
> used.
How is that different from Kent's SIX locks other than you can take an
rwsem for write immediately (SIX locks have to be taken for Intent and
then Upgraded)?
next prev parent reply other threads:[~2024-10-16 18:06 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-16 4:35 [RFC 0/2] rwsem: introduce upgrade_read interface lizhe.67
2024-10-16 4:35 ` [RFC 1/2] " lizhe.67
2024-10-16 4:56 ` Christoph Hellwig
2024-10-16 7:33 ` lizhe.67
2024-10-16 7:36 ` Christoph Hellwig
2024-10-16 8:00 ` lizhe.67
2024-10-16 8:03 ` Christoph Hellwig
2024-10-16 8:13 ` lizhe.67
2024-10-16 11:51 ` Matthew Wilcox
2024-10-16 12:21 ` Christoph Hellwig
2024-10-16 11:49 ` Matthew Wilcox
2024-10-17 6:23 ` lizhe.67
2024-10-16 14:23 ` Waiman Long
2024-10-16 18:05 ` Matthew Wilcox [this message]
2024-10-16 18:39 ` Waiman Long
2024-10-17 6:46 ` lizhe.67
2024-10-17 15:05 ` Christoph Hellwig
2024-10-17 17:36 ` Waiman Long
2024-10-18 5:06 ` Christoph Hellwig
2024-10-16 4:36 ` [RFC 2/2] khugepaged: use upgrade_read() to optimize collapse_huge_page lizhe.67
2024-10-16 11:53 ` Matthew Wilcox
2024-10-17 6:18 ` lizhe.67
2024-10-17 13:20 ` Matthew Wilcox
2024-10-18 6:37 ` lizhe.67
2024-10-23 7:27 ` kernel test robot
2024-10-16 8:09 ` [RFC 0/2] rwsem: introduce upgrade_read interface Peter Zijlstra
2024-10-16 8:53 ` lizhe.67
2024-10-16 12:10 ` Peter Zijlstra
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