linux-kernel - Re: [PATCH 2/2] x86/MCE: Add command line option to extend MCE Records pool

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Date: Mon, 12 Feb 2024 22:27:41 +0100
From: Borislav Petkov <bp@...en8.de>
To: "Paul E. McKenney" <paulmck@...nel.org>
Cc: "Luck, Tony" <tony.luck@...el.com>,
	Yazen Ghannam <yazen.ghannam@....com>,
	"Naik, Avadhut" <avadnaik@....com>,
	"Mehta, Sohil" <sohil.mehta@...el.com>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-edac@...r.kernel.org" <linux-edac@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Avadhut Naik <avadhut.naik@....com>
Subject: Re: [PATCH 2/2] x86/MCE: Add command line option to extend MCE
 Records pool

On Mon, Feb 12, 2024 at 12:44:06PM -0800, Paul E. McKenney wrote:
> If it is the #MC adding new memory, agreed.
> 
> If the #MC is simply traversing the list, and the interrupted context
> was in the midst of adding a new element, this should be no worse than
> some other CPU traversing the list while this CPU is in the midst of
> adding a new element.

Right, Tony answered which context is doing what.

What I'm still scratching my head over is, why grab a spinlock around

	list_add_rcu(&chunk->next_chunk, &pool->chunks);

?

That's the part that looks really weird.

And that's the interrupted context, yap.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette