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[209.85.208.180]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-5334ea88e53sm132582e87.269.2024.08.21.23.56.25 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 Aug 2024 23:56:25 -0700 (PDT) Received: by mail-lj1-f180.google.com with SMTP id 38308e7fff4ca-2f3ce5bc6adso3684091fa.1 for ; Wed, 21 Aug 2024 23:56:25 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCXoR1Efxutvu3tyqqVQxmcGcswCp9prH0TMSsW4wR3jD64P/ma8wAAD+uHVs8N1w3q2Iy0ay+BEyQ==@kvack.org X-Received: by 2002:a05:651c:1502:b0:2ef:22ef:a24e with SMTP id 38308e7fff4ca-2f3f881e268mr32445201fa.10.1724309784839; Wed, 21 Aug 2024 23:56:24 -0700 (PDT) MIME-Version: 1.0 References: <20240817062449.21164-1-21cnbao@gmail.com> <7050deab-e99c-4c83-b7b9-b5dad42f4e95@redhat.com> In-Reply-To: From: Linus Torvalds Date: Thu, 22 Aug 2024 14:56:08 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 0/4] mm: clarify nofail memory allocation To: Michal Hocko Cc: Yafang Shao , David Hildenbrand , Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org, 42.hyeyoo@gmail.com, cl@linux.com, hailong.liu@oppo.com, hch@infradead.org, iamjoonsoo.kim@lge.com, penberg@kernel.org, rientjes@google.com, roman.gushchin@linux.dev, urezki@gmail.com, v-songbaohua@oppo.com, vbabka@suse.cz, virtualization@lists.linux.dev Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Queue-Id: 00904140022 X-Rspamd-Server: rspam01 X-Stat-Signature: 6pjt5yt37n6g8a5ozjz93u4xripthsyk X-HE-Tag: 1724309788-191709 X-HE-Meta: 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 yJmJgXfg 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 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 Thu, 22 Aug 2024 at 14:40, Linus Torvalds wrote: > > I did find three cases of kvcalloc(NOFAIL) in the nouveau driver and > one in erofs. It's not clear that any of them make much sense (or that > the erofs one is actually a large allocation). Oh, and I missed one in btrfs because it needed five lines of context due to being the allocation from hell. That said, yes, the vmalloc case at least has no fragmentation issues, but I do think even that needs to be size limited for sanity. The size limit might be larger than a couple of pages, but not _hugely_ larger. You can't just say "I want a megabyte, and you can't fail me". That kind of code is garbage, and needs to be called out for being garbage. Linus