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[209.85.208.51]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a86e5487aa5sm71481266b.31.2024.08.26.23.57.28 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Aug 2024 23:57:28 -0700 (PDT) Received: by mail-ed1-f51.google.com with SMTP id 4fb4d7f45d1cf-5a10835487fso7655319a12.1 for ; Mon, 26 Aug 2024 23:57:28 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCUWZP0znufSGdq98AQjACw2nlTvXQokmfaYtH4+OzUtPNLDf7GwYlzQVR5LPQq3E00K1mqCE/48Cw==@kvack.org X-Received: by 2002:a05:6402:518d:b0:5c0:99ff:7c85 with SMTP id 4fb4d7f45d1cf-5c099ff84b0mr6792763a12.18.1724741847852; Mon, 26 Aug 2024 23:57:27 -0700 (PDT) MIME-Version: 1.0 References: <59e90825-4efa-4384-8286-06c0235304dc@redhat.com> In-Reply-To: From: Linus Torvalds Date: Tue, 27 Aug 2024 18:57:09 +1200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 0/4] mm: clarify nofail memory allocation To: Vlastimil Babka Cc: David Hildenbrand , Michal Hocko , Barry Song <21cnbao@gmail.com>, Yafang Shao , 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, virtualization@lists.linux.dev Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: E8264140013 X-Stat-Signature: 3ujdgu3z58y3jigkjiicypg6gjh1d66r X-Rspam-User: X-HE-Tag: 1724741851-18079 X-HE-Meta: U2FsdGVkX1/N5YRelhxK7pFNKaDIhuqmHhWNiqh7hPzDCWqNrbdFe8jrUDVtlzqrXCm54a2ZwFR+w0gxbBxnGtSpsHe0n6HOOMhx67dkyTPkXyv5jvtGokLDOGQ2xcmZH0+KCXUuSZzLpeBR7FFED80I9KXkQ1cF/lcogpehbQC5hLh2n6+S+AHS8SMOZPSQ1oLiGf2ZoyhaYQMREZ4Hy2SKrnky/AktEqvOX+Roy4qDxWXZmO+tTgyTQFrmJ3kCi1QszXUZ8mX2Fi14e39wSC50xiiRnUSbfvrrxtr42D+dV2ZUQED23IFYiBCdRWnnx+SPRRPa5MQjyXue4W4+qQwzpRQU/4kbRnfg3JRoGaszIngxlD3nzntM7nL7/D7+Ix6ZOC4IsclEBaAuHKWqcl45QpSLs5BcyXFleEowkXDGEYI6Ugyv/7bKOZL9ekq+XpkGjDgNr2JXv3E3BEHPU11LBNnWOSsBnUxsi7q/3ffYAKmKYXgu++uG2gvC3YiwoNJgHKl6K7x6+LWFd+E/NmBXIprP2kXIYz85n4yZ027Q+lnvUdjMHgMuS6VAmY2lzSO5EkpzVeW+dfawCW3eaPXNiFYt0TpfMchUH2/nVo3PNSMvcvZ+dkGb5YemOSbyWY2dW43MEQQRPS95TzewkLmk7wnHE35td+WKtfHjtNYzCozFgmPu4ZmZHnVkdAYJ+1bCkxFK/nHcTTysQr+BBmf52Ki/G4BT4UhiPCiIcWpUHEpGeI1Cp/Ry1QGgXTMGvoQD21+xL+mYTxKoF7wmCs+7LCM0NmCm4Fkv8gjB3vZXWAezmQmCwqvpvswlDjOiFI7z/NXRBAnkSHRJbMTOLGQkzX9YEqCqxxVSIQCCpBUCQcsCDxz6zi6HI0yZemRSnGfEzhVXtP6ZNurl9v0ThRlIjbEZhGRDMqB5VdUiRFN7C18zZMAb713XRC0PW1iSVsBY3qI2MGymamB7dXV 4pE6Fh/j 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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 Tue, 27 Aug 2024 at 00:10, Vlastimil Babka wrote: > > Right now we give the WARN_ON_ONCE() (for !can_direct_reclaim) only when > we're about to actually return NULL, so the memory has to be depleted > already. To make it easier to find the offenders much more reliably, we > should consider doing it sooner, but also not add unnecessary overhead to > allocator fastpaths just because of the potentially buggy users. Ack. Sounds like a sane model to me. And I agree that __alloc_pages_slowpath() is likely a reasonable middle path between "catch misuses, but don't put it in the hotpath". Linus