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[109.81.94.157]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a7aabd8cae5sm91255666b.146.2024.07.24.06.47.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jul 2024 06:47:47 -0700 (PDT) Date: Wed, 24 Jul 2024 15:47:46 +0200 From: Michal Hocko To: Christoph Hellwig Cc: Vlastimil Babka , Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org, 42.hyeyoo@gmail.com, cl@linux.com, iamjoonsoo.kim@lge.com, lstoakes@gmail.com, penberg@kernel.org, rientjes@google.com, roman.gushchin@linux.dev, urezki@gmail.com, v-songbaohua@oppo.com, virtualization@lists.linux.dev, hailong.liu@oppo.com, torvalds@linux-foundation.org Subject: Re: [PATCH RFC 5/5] non-mm: discourage the usage of __GFP_NOFAIL and encourage GFP_NOFAIL Message-ID: References: <20240724085544.299090-1-21cnbao@gmail.com> <20240724085544.299090-6-21cnbao@gmail.com> <68ee812b-3b96-4c8b-9a54-70d4742488bb@suse.cz> <400b2f6f-f7f0-4888-99ee-7327faad7e5c@suse.cz> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Wed 24-07-24 06:38:41, Christoph Hellwig wrote: > On Wed, Jul 24, 2024 at 03:33:19PM +0200, Vlastimil Babka wrote: > > > I do not see this a problem. There is no real reason to have a NOWAIT > > > allocation down the stack that has a different fallback strategy. > > > I am not saying that this is the current practice because I do not know > > > that but I am saying that this is not impossible to imagine and it makes > > > scoped NOFAIL context subtle and error prone. > > > > I don't think Christoph proposed scoped NOFAIL, just use scoped NOFS/NOIO > > together with GFP_KERNEL_NOFAIL intead of introducing GFP_NOFS_NOFAIL. > > Yes, exactly. > > And I didn't think Michal thought I meant something different, maybe > that's why it felt really confusing. OK, now it makes more sense ;) I have absolutely no objections to prefering scoped NO{FS,IO} interfaces of course. And that would indeed eliminate a need for defining GFP_NO{FS,IO}_NOFAIL alternatives. Thanks for the clarification. -- Michal Hocko SUSE Labs