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From: Christoph Lameter <cl@gentwo.de>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Aaron Tomlin <atomlin@atomlin.com>,
	 Frederic Weisbecker <frederic@kernel.org>,
	 Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org,  linux-mm@kvack.org
Subject: Re: [PATCH 3/5] mm/vmstat: use cmpxchg loop in cpu_vm_stats_fold
Date: Thu, 2 Feb 2023 15:38:58 +0100 (CET)	[thread overview]
Message-ID: <fb371ac-cf69-28a6-eca0-6caccda4e0b8@gentwo.de> (raw)
In-Reply-To: <20230201195104.460373427@redhat.com>

On Wed, 1 Feb 2023, Marcelo Tosatti wrote:

> In preparation to switch vmstat shepherd to flush
> per-CPU counters remotely, use a cmpxchg loop
> instead of a pair of read/write instructions.

You are mixing full atomic cmpxchg and  per cpu atomic cmpxchg? That does
not work.

I thought you would only run this while the kernel is not active on the
remote cpu? Then you dont need any cmpxchg and you can leave the function
as is.


  reply	other threads:[~2023-02-02 14:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-01 19:50 [PATCH 0/5] fold per-CPU vmstats remotely Marcelo Tosatti
2023-02-01 19:50 ` [PATCH 1/5] mm/vmstat: remove remote node draining Marcelo Tosatti
2023-02-01 19:50 ` [PATCH 2/5] mm/vmstat: switch counter modification to cmpxchg Marcelo Tosatti
2023-02-01 19:50 ` [PATCH 3/5] mm/vmstat: use cmpxchg loop in cpu_vm_stats_fold Marcelo Tosatti
2023-02-02 14:38   ` Christoph Lameter [this message]
2023-02-02 15:54     ` Marcelo Tosatti
2023-02-03  9:34       ` Christoph Lameter
2023-02-03 18:52         ` Marcelo Tosatti
2023-02-06  9:42           ` Christoph Lameter
2023-02-06 19:10             ` Marcelo Tosatti
2023-02-06 19:19   ` Matthew Wilcox
2023-02-01 19:50 ` [PATCH 4/5] mm/vmstat: switch vmstat shepherd to flush per-CPU counters remotely Marcelo Tosatti
2023-02-01 19:50 ` [PATCH 5/5] mm/vmstat: refresh stats remotely instead of via work item Marcelo Tosatti

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