From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v4 1/5] getcpu_cache system call: cache CPU number of
 running thread
Date: Wed, 24 Feb 2016 12:11:15 +0100 (CET)
Message-ID: <alpine.DEB.2.11.1602241206020.3670@nanos>
References: <1456270120-7560-1-git-send-email-mathieu.desnoyers@efficios.com> <1456270120-7560-2-git-send-email-mathieu.desnoyers@efficios.com>
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To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Russell King <linux@arm.linux.org.uk>, Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Paul Turner <pjt@google.com>, Andrew Hunter <ahh@google.com>, Peter Zijlstra <peterz@infradead.org>, Andy Lutomirski <luto@amacapital.net>, Andi Kleen <andi@firstfloor.org>, Dave Watson <davejwatson@fb.com>, Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>, Steven Rostedt <rostedt@goodmis.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Josh Triplett <josh@joshtriplett.org>, Linus Torvalds <torvalds@linux-foundation.org>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Michael Kerrisk <mtk.manpages@gmail.com>
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On Tue, 23 Feb 2016, Mathieu Desnoyers wrote:
> +/*
> + * If parent process has a thread-local ABI, the child inherits. Only applies
> + * when forking a process, not a thread.
> + */
> +void getcpu_cache_fork(struct task_struct *t)
> +{
> +	t->cpu_cache = current->cpu_cache;
> +}
> +
> +void getcpu_cache_execve(struct task_struct *t)
> +{
> +	t->cpu_cache = NULL;
> +}
> +
> +void getcpu_cache_exit(struct task_struct *t)
> +{
> +	t->cpu_cache = NULL;
> +}

That's hardly worth a function call. Please inline.

> +/*
> + * sys_getcpu_cache - setup getcpu cache for caller thread
> + */
> +SYSCALL_DEFINE3(getcpu_cache, int, cmd, int32_t __user * __user *, cpu_cachep,
> +		int, flags)
> +{
> +	if (unlikely(flags))
> +		return -EINVAL;

New line for readability sake.

> +	switch (cmd) {
> +	case GETCPU_CACHE_GET:

Other than that: Reviewed-by: Thomas Gleixner <tglx@linutronix.de>