From: Thomas Gleixner <tglx@linutronix.de>
To: "Zengtao (B)" <prime.zeng@hisilicon.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: RE: [PATCH] cputime: Fix timeval-->cputime conversion
Date: Mon, 1 Feb 2016 09:43:14 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.11.1602010942150.25254@nanos> (raw)
In-Reply-To: <678F3D1BB717D949B966B68EAEB446ED0A6B5423@SZXEMA509-MBX.china.huawei.com>
On Mon, 1 Feb 2016, Zengtao (B) wrote:
> Hi Arnd:
> I have got a new idea about the problem:
> In include/linux/time64.h
> #define NSEC_PER_SEC 1000000000L
> I think we should change it to
> #define NSEC_PER_SEC 1000000000LL
>
> My reason is :
> 1. when it is used in a multiplication, it will easily get overflow.
> 2. when it don't get overflow, the change has no side affect.
That's not a good idea. NSEC_PER_SEC is used in lots of places with 32bit
storage. I really don't want to mop up all the fallout.
Thanks,
tglx
next prev parent reply other threads:[~2016-02-01 8:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-28 7:02 [PATCH] cputime: Fix timeval-->cputime conversion zengtao
2016-01-28 8:22 ` Thomas Gleixner
2016-01-28 11:52 ` Arnd Bergmann
2016-01-29 3:12 ` Zengtao (B)
2016-01-29 8:46 ` Arnd Bergmann
2016-01-30 2:31 ` Zengtao (B)
2016-02-01 3:51 ` Zengtao (B)
2016-02-01 8:43 ` Thomas Gleixner [this message]
2016-02-02 2:57 ` Zengtao (B)
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