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Fri, 23 Aug 2019 12:22:45 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48F1A307691; Fri, 23 Aug 2019 14:22:10 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 67A3B201E04D9; Fri, 23 Aug 2019 14:22:42 +0200 (CEST) Date: Fri, 23 Aug 2019 14:22:42 +0200 From: Peter Zijlstra To: Jason Gunthorpe Cc: Daniel Vetter , Andrew Morton , LKML , Linux MM , DRI Development , Intel Graphics Development , Ingo Molnar , Michal Hocko , David Rientjes , Christian =?iso-8859-1?Q?K=F6nig?= , =?iso-8859-1?B?Suly9G1l?= Glisse , Masahiro Yamada , Wei Wang , Andy Shevchenko , Thomas Gleixner , Jann Horn , Feng Tang , Kees Cook , Randy Dunlap , Daniel Vetter Subject: Re: [PATCH 3/4] kernel.h: Add non_block_start/end() Message-ID: <20190823122242.GN2349@hirez.programming.kicks-ass.net> References: <20190820081902.24815-1-daniel.vetter@ffwll.ch> <20190820081902.24815-4-daniel.vetter@ffwll.ch> <20190820202440.GH11147@phenom.ffwll.local> <20190822161428.c9e4479207386d34745ea111@linux-foundation.org> <20190823121234.GB12968@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190823121234.GB12968@ziepe.ca> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Aug 23, 2019 at 09:12:34AM -0300, Jason Gunthorpe wrote: > I still haven't heard a satisfactory answer why a whole new scheme is > needed and a simple: > > if (IS_ENABLED(CONFIG_DEBUG_ATOMIC_SLEEP)) > preempt_disable() > > isn't sufficient to catch the problematic cases during debugging?? > IMHO the fact preempt is changed by the above when debugging is not > material here. I think that information should be included in the > commit message at least. That has a much larger impact and actually changes behaviour, while the relatively simple patch Daniel proposed only adds a warning but doesn't affect behaviour.