public inbox for [email protected]  

help / color / mirror / Atom feed

From: Li, Yong <[email protected]>
To: Nathan Bossart <[email protected]>
Cc: Andres Freund <[email protected]>
Cc: [email protected] <[email protected]>
Subject: Re: locked reads for atomics
Date: Wed, 17 Jan 2024 03:48:43 +0000
Message-ID: <[email protected]> (raw)
In-Reply-To: <20231127210030.GA140335@nathanxps13>
References: <20231110205128.GB1315705@nathanxps13>
	<[email protected]>
	<20231111023813.GB1408159@nathanxps13>
	<[email protected]>
	<20231111025529.GA1409540@nathanxps13>
	<20231127210030.GA140335@nathanxps13>



> On Nov 28, 2023, at 05:00, Nathan Bossart <[email protected]> wrote:
> 
> External Email
> 
> Here's a v2 of the patch set in which I've attempted to address all
> feedback.  I've also added a pg_write_membarrier_u* pair of functions that
> provide an easy way to write to an atomic variable with full barrier
> semantics.  In the generic implementation, these are just aliases for an
> atomic exchange.
> 
> 0002 demonstrates how these functions might be used to eliminate the
> arch_lck spinlock, which is only ever used for one boolean variable.  My
> hope is that the membarrier functions make eliminating spinlocks for
> non-performance-sensitive code easy to reason about.
> 
> (We might be able to use a pg_atomic_flag instead for 0002, but that code
> seems intended for a slightly different use-case and has more complicated
> barrier semantics.)
> 
> --
> Nathan Bossart
> Amazon Web Services: https://aws.amazon.com

Hi Nathan,

The patch looks good to me.

The patch adds two pairs of atomic functions that provide full-barrier semantics to atomic read/write operations. The patch also includes an example of how this new functions can be used to replace spin locks.

The patch applies cleanly to HEAD. “make check-world” also runs cleanly with no error.  I am moving it to Ready for Committers.

Regards,
Yong

view thread (15+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected]
  Subject: Re: locked reads for atomics
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox