From: Jens Axboe <axboe@kernel.dk>
To: kemi <kemi.wang@intel.com>, Andi Kleen <ak@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>, Darrick J Wong <darrick.wong@oracle.com>,
Eric Biggers <ebiggers@google.com>,
Andreas Gruenbacher <agruenba@redhat.com>,
Jeff Layton <jlayton@redhat.com>,
Dave <dave.hansen@linux.intel.com>,
Andi Kleen <andi.kleen@intel.com>,
Tim Chen <tim.c.chen@intel.com>,
Ying Huang <ying.huang@intel.com>, Aaron Lu <aaron.lu@intel.com>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] buffer: Avoid setting buffer bits that are already set
Date: Tue, 24 Oct 2017 07:50:27 -0600 [thread overview]
Message-ID: <5677e6be-38ab-edb3-36db-094452c61d1e@kernel.dk> (raw)
In-Reply-To: <131ef377-7edb-738c-4ed1-debac7857434@intel.com>
On 10/23/2017 07:25 PM, kemi wrote:
>
>
> On 2017年10月24日 09:21, Andi Kleen wrote:
>> kemi <kemi.wang@intel.com> writes:
>>>
>>> I'll see if I can find some
>>>> time to implement the above in a nice way.
>>>
>>> Agree. Maybe something like test_and_set_bit() would be more suitable.
>>
>> test_and_set_bit is a very different operation for the CPU because
>> it is atomic for both. But we want the initial read to not
>> be atomic.
>>
>
> I meant to express the meaning of test before setting bit.
> Apologize to make you confused.
That's why I suggested something like set_bit_if_not_set(),
test_and_set_bit() is both already used and has entirely
different semantics.
--
Jens Axboe
prev parent reply other threads:[~2017-10-24 13:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-23 15:27 [PATCH] buffer: Avoid setting buffer bits that are already set Kemi Wang
2017-10-23 16:19 ` Jens Axboe
2017-10-24 0:52 ` kemi
2017-10-24 1:21 ` Andi Kleen
2017-10-24 1:25 ` kemi
2017-10-24 13:50 ` Jens Axboe [this message]
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