Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 21 May 2019 16:47:13 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Christopher Lameter <cl@linux.com>
Cc:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        David Rientjes <rientjes@google.com>,
        Christian =?iso-8859-1?Q?K=F6nig?= <christian.koenig@amd.com>,
        =?iso-8859-1?B?Suly9G1l?= Glisse <jglisse@redhat.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Wei Wang <wvw@google.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jann Horn <jannh@google.com>, Feng Tang <feng.tang@intel.com>,
        Kees Cook <keescook@chromium.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH] kernel.h: Add non_block_start/end()
Message-ID: <20190521144713.GX32329@dhcp22.suse.cz>
References: <20190521100611.10089-1-daniel.vetter@ffwll.ch>
 <0100016adad909d8-e6c9c310-36e0-4bdd-80fd-5df1a1660041-000000@email.amazonses.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <0100016adad909d8-e6c9c310-36e0-4bdd-80fd-5df1a1660041-000000@email.amazonses.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue 21-05-19 14:43:38, Cristopher Lameter wrote:
> On Tue, 21 May 2019, Daniel Vetter wrote:
> 
> > In some special cases we must not block, but there's not a
> > spinlock, preempt-off, irqs-off or similar critical section already
> > that arms the might_sleep() debug checks. Add a non_block_start/end()
> > pair to annotate these.
> 
> Just putting preempt on/off around these is not sufficient?

It is not a critical section. It is a _debugging_ facility to help
discover blocking contexts.
-- 
Michal Hocko
SUSE Labs