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Date:   Wed, 28 Mar 2018 10:26:14 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Andy Lutomirski <luto@amacapital.net>,
        Dave Watson <davejwatson@fb.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-api <linux-api@vger.kernel.org>,
        Paul Turner <pjt@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Russell King <linux@arm.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Andrew Hunter <ahh@google.com>,
        Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
        Ben Maurer <bmaurer@fb.com>, rostedt <rostedt@goodmis.org>,
        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>,
        Alexander Viro <viro@zeniv.linux.org.uk>
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Subject: Re: [RFC PATCH for 4.17 02/21] rseq: Introduce restartable
 sequences system call (v12)
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Thread-Topic: rseq: Introduce restartable sequences system call (v12)
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----- On Mar 28, 2018, at 7:22 AM, Peter Zijlstra peterz@infradead.org wrote:

> On Tue, Mar 27, 2018 at 12:05:23PM -0400, Mathieu Desnoyers wrote:
>> +/*
>> + * struct rseq_cs is aligned on 4 * 8 bytes to ensure it is always
>> + * contained within a single cache-line. It is usually declared as
>> + * link-time constant data.
>> + */
>> +struct rseq_cs {
>> +	/* Version of this structure. */
>> +	uint32_t version;
>> +	/* enum rseq_cs_flags */
>> +	uint32_t flags;
>> +	LINUX_FIELD_u32_u64(start_ip);
>> +	/* Offset from start_ip. */
>> +	LINUX_FIELD_u32_u64(post_commit_offset);
>> +	LINUX_FIELD_u32_u64(abort_ip);
>> +} __attribute__((aligned(4 * sizeof(uint64_t))));
> 
> What's with the uint32_t ? The normal Linux API type is __u32 afaik.

Will fix. Working on both kernel and user-space code in parallel kind
of does that to the brain. ;-)

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com