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[109.81.94.157]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-427d2a6efc5sm45221955e9.21.2024.07.19.02.33.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jul 2024 02:33:18 -0700 (PDT) Date: Fri, 19 Jul 2024 11:33:17 +0200 From: Michal Hocko To: Vlastimil Babka Cc: Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org, Barry Song , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com> Subject: Re: [PATCH RFC] mm: warn potential return NULL for kmalloc_array and kvmalloc_array with __GFP_NOFAIL Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: EFE45A0027 X-Stat-Signature: ro4xnodcp6pdexh5yda71ec7cg8nd9y7 X-Rspam-User: X-HE-Tag: 1721381599-448694 X-HE-Meta: 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 7j49Hm7V GznTGq4JM90+AijpJP4SxMA4n6auGV9dZfD5xG3uTaYM0daLkRWjW7LOQkuF1aS0TlmbMKwFjxTeoHWsbmbdrdi3hbF3C7qsrcW4K/wzm8xftmMdgkTP1RuVfuiJtklhNDUQX4CjvagbCmjkkTA/c/tKuLpxBtZbAi00B4I7Vq63TItluu9WdyiF889lttkmUqIEKPlJyxDQZzj/oavJ2t5qMT6AJkwVi2lNc6DqtiRVJK9NdaNGMBFnRybAjjchqre12sL6VGo46ayfrq/2Mc5WBReBCmvT5N4rWSgUV4qveamS0xUGpWNw3Umw+Z23ATBgqAd8xlV8BxRt6Ju5Ct0VffAfwv8gxSwRe6pKXocUDLu/RcjzuU/7W1LhkQPEwPaLgumbT2xxK9CwLjzM2hjMQNA== 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 19-07-24 10:50:07, Vlastimil Babka wrote: [...] > That wouldn't mean the busy loop is a correct and supported practice. It > would just mean it's the least bad of the bad options we have to deal with > an allocation that's wrong but we didn't catch soon enough in the development. So you want to make those potential BUG_ONs hard/soft lockups (not sure all arches have a reliable detection) instead? -- Michal Hocko SUSE Labs