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AJvYcCV644gt7qv58uqpHfKYW3Wmgqi84ei8gi1wB5+sZQyjGrLE3auuR2QlCUuKymG724Qfi4ch0Q6Oq5R0IU3XkZxVi3A= X-Gm-Message-State: AOJu0Yz9yubPJVC6jQPIJaMHg5wPaatytEtxOa5p11BccOFPCu2pPcFe xaJWjUS9UiZP3PGteXR0Q2olWAMZTB/fxMWZd0HoaBUdlrJaRfzIelO/6b2ucfvNTHPeA4mr1EX T8AywROV4fHMExRLj7BzUMGDgzsM= X-Google-Smtp-Source: AGHT+IG4DIe4Et7O2a/YpW0nAxGJb4dIr4riVB0k57W4nwlwyG4kcu3XmUaNtzrk3EcFINQPVI/1pxzrOsi6el1O8mM= X-Received: by 2002:a05:6102:4b88:b0:48f:c2dd:3520 with SMTP id ada2fe7eead31-491598a8bd6mr10729016137.11.1721383142858; Fri, 19 Jul 2024 02:59:02 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Barry Song <21cnbao@gmail.com> Date: Fri, 19 Jul 2024 21:58:51 +1200 Message-ID: Subject: Re: [PATCH RFC] mm: warn potential return NULL for kmalloc_array and kvmalloc_array with __GFP_NOFAIL To: Michal Hocko Cc: akpm@linux-foundation.org, linux-mm@kvack.org, Barry Song , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: c3oyaef48hheohfmqy4eot5cs95mzroq X-Rspamd-Queue-Id: E9BF72000B X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1721383143-908959 X-HE-Meta: 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 rq4VIZGF 8a55pB1ZqPQTbKN7qat6QtxfIy0wyPhW1ABFYnbH9BtYdfNWPIAztfPEZIsNHZNao3nkDamYTIIpYUfvbK+kFni6dVGXjQwqMymhW6kmtq7b4gNNspJH7lhB7kCZDHuoHC+UG0Pdk+6/cEizK+CSj1SYzdocwqlllHhwQHJLaSVJzHTJtoEri6SHa0ZdHWL12Ag/CXV+EZgiISDtg8NLu0MP69qIiWVUe/qABoAWYtlu9d11LC1YVVQ8QDP3AZNx4jji20DdrmfBvONV8QNQErd7whgw+yP4oPGX12HNCiul6lNDBeLzx6U7/8WoQAHkQGaNDmfViFEj6YBpz4HFhqizly8rjkWT+6xYSTaYP8og8HOV4QRJpGVKlfBE+6y7KqFNqXytC/v9Cjr15QvaRH0kblFCWLwi5xH58C3lqtWLSd98EW9WQPgiy1DrhJ/nqtkpfv8zpbV3xJPTFGXU2jhz928hnDEMne/7z 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: List-Subscribe: List-Unsubscribe: On Fri, Jul 19, 2024 at 9:45=E2=80=AFPM Michal Hocko wrot= e: > > On Fri 19-07-24 21:36:38, Barry Song wrote: > > And I believe that even most MM experts have no idea when GFP_NOFAIL > > will fail. This is so bad to keep it as is. > > GFP_NOFAIL doesn't fail in any supported scenarios. We are talking how > to deal with those that are unsupported. I am not sure how much helpful > it is to document all potential gfp combinations that make no-sense. Sorry, I don't see any point from what you are saying. You are simply claim= ing this is the fault of those calling "unsupported" APIs while lacking a valid= way to stop this from happening. Bear in mind, Everything which is not forbidde= n is allowed. I don't think maintainers outside mm know what are supported and what are not supported. an "unsupported" scenario can find a way to come into mainline easily. > -- > Michal Hocko > SUSE Labs Thanks Barry