linux-kernel - Re: [PATCH 0/3] nohz: Convert tick dependency mask to atomic

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Date:	Thu, 31 Mar 2016 11:20:31 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Frederic Weisbecker <fweisbec@...il.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 0/3] nohz: Convert tick dependency mask to atomic_t

On Thu, Mar 31, 2016 at 08:54:19AM +0200, Ingo Molnar wrote:
> Sounds good to me! I also volunteer the x86 architecture to be the guinea pig to 
> convert thread_info::flags to atomic_t ;-) [*]

So I'm not sure we can do this one arch at a time; all the TIF
manipulators live in include/linux/thread_info.h and are shared across
all archs.

Another thing to look out for is that set_bit() uses LOCK BTS when the
bit is not a compile time constant, we do not have an atomic_*() version
of that. Now I'm not sure if this matters, we might never end up
triggering that code path for TIF flags.