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Date: Thu, 3 Apr 2025 17:05:13 +0200
From: Ingo Molnar <mingo@kernel.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, Juergen Gross <jgross@suse.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 40/41] x86/alternatives: Rename 'text_poke_sync()' to
 'text_poke_sync_each_cpu()'
Message-ID: <Z-6jqf6QqRkAnTz8@gmail.com>
References: <20250327205355.378659-1-mingo@kernel.org>
 <20250327205355.378659-41-mingo@kernel.org>
 <DA9DB9BF-2179-4C53-86A8-6205346AA76F@zytor.com>
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* H. Peter Anvin <hpa@zytor.com> wrote:

> Is that the only use case we have for syncing all CPUs?

So there's:

- kernel/sched/membarrier.c's ipi_sync_core() which does sync_core(), 
  but it's embedded into a larger array of IPI handlers, called via 
  smp_call_function_many()/on_each_cpu_mask(), so I don't think 
  functionality can be shared there.

- there's arch/x86/kernel/cpu/mce/core.c's machine_check_poll() handler 
  and the kill_me_maybe() function, but these are single thread.

- then there's arch/x86/kernel/static_call.c's 
  __static_call_update_early(), used indirectly by 
  arch/x86/xen/enlighten.c and arch/x86/xen/enlighten_pv.c, but these 
  are single-threaded too due to being early boot code.

So not much I think - at least what I've managed to find.

Thanks,

	Ingo