From: Leon Romanovsky <leon@leon.nu>
To: Geliang Tang <geliangtang@163.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Hugh Dickins <hughd@google.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Joonsoo Kim <js1304@gmail.com>, Arnd Bergmann <arnd@arndb.de>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Oleg Nesterov <oleg@redhat.com>, Linux-MM <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] mm/nommu: drop unlikely behind BUG_ON()
Date: Mon, 5 Oct 2015 10:49:19 +0300 [thread overview]
Message-ID: <20151005074919.GA10359@leon.nu> (raw)
In-Reply-To: <20151005020406.GB8831@linux-uzut.site>
On Sun, Oct 04, 2015 at 07:04:06PM -0700, Davidlohr Bueso wrote:
> On Sun, 04 Oct 2015, Leon Romanovsky wrote:
>
> >On Sun, Oct 4, 2015 at 9:18 AM, Geliang Tang <geliangtang@163.com> wrote:
> >>BUG_ON() already contain an unlikely compiler flag. Drop it.
> >It is not the case if CONFIG_BUG and HAVE_ARCH_BUG_ON are not set.
>
> Yeah, but that's like the 1% of the cases -- and those probably don't even care
> about the branch prediction (I could be wrong). So overall I like getting rid of
> explicit BUG_ON(unlikely(... calls. In fact there's a _reason_ why there are so
> few of them in the kernel.
I agree with you that this change is welcomed and I would like to see it
is accepted.
My main concern that I would expect to see it's coming after the change
of BUG_ON definition to be similar in all places, with "unlikely" in all
definitions, and not instead.
>
> Thanks,
> Davidlohr
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WARNING: multiple messages have this Message-ID (diff)
From: Leon Romanovsky <leon@leon.nu>
To: Geliang Tang <geliangtang@163.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Hugh Dickins <hughd@google.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Joonsoo Kim <js1304@gmail.com>, Arnd Bergmann <arnd@arndb.de>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Oleg Nesterov <oleg@redhat.com>, Linux-MM <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/3] mm/nommu: drop unlikely behind BUG_ON()
Date: Mon, 5 Oct 2015 10:49:19 +0300 [thread overview]
Message-ID: <20151005074919.GA10359@leon.nu> (raw)
In-Reply-To: <20151005020406.GB8831@linux-uzut.site>
On Sun, Oct 04, 2015 at 07:04:06PM -0700, Davidlohr Bueso wrote:
> On Sun, 04 Oct 2015, Leon Romanovsky wrote:
>
> >On Sun, Oct 4, 2015 at 9:18 AM, Geliang Tang <geliangtang@163.com> wrote:
> >>BUG_ON() already contain an unlikely compiler flag. Drop it.
> >It is not the case if CONFIG_BUG and HAVE_ARCH_BUG_ON are not set.
>
> Yeah, but that's like the 1% of the cases -- and those probably don't even care
> about the branch prediction (I could be wrong). So overall I like getting rid of
> explicit BUG_ON(unlikely(... calls. In fact there's a _reason_ why there are so
> few of them in the kernel.
I agree with you that this change is welcomed and I would like to see it
is accepted.
My main concern that I would expect to see it's coming after the change
of BUG_ON definition to be similar in all places, with "unlikely" in all
definitions, and not instead.
>
> Thanks,
> Davidlohr
next prev parent reply other threads:[~2015-10-05 7:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-04 6:18 [PATCH 1/3] scsi: drop unlikely behind BUG_ON() Geliang Tang
2015-10-04 6:18 ` [PATCH 2/3] sched/core: " Geliang Tang
2015-10-04 6:18 ` [PATCH 3/3] mm/nommu: " Geliang Tang
2015-10-04 6:18 ` Geliang Tang
2015-10-04 11:02 ` Leon Romanovsky
2015-10-04 11:02 ` Leon Romanovsky
2015-10-05 2:04 ` Davidlohr Bueso
2015-10-05 2:04 ` Davidlohr Bueso
2015-10-05 7:49 ` Leon Romanovsky [this message]
2015-10-05 7:49 ` Leon Romanovsky
2015-10-05 1:50 ` Davidlohr Bueso
2015-10-05 1:50 ` Davidlohr Bueso
2015-10-05 2:30 ` Geliang Tang
2015-10-05 2:30 ` Geliang Tang
2015-10-05 3:37 ` Davidlohr Bueso
2015-10-05 3:37 ` Davidlohr Bueso
2015-10-04 14:33 ` [PATCH 1/3] scsi: " Bart Van Assche
2015-10-04 14:33 ` Bart Van Assche
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