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Sat, 1 Apr 2023 19:33:28 +0100 From: David Laight To: 'Vlastimil Babka' , "linux-mm@kvack.org" CC: "linux-kernel@vger.kernel.org" , "patches@lists.linux.dev" Subject: RE: [PATCH] mm: remove all the slab allocators Thread-Topic: [PATCH] mm: remove all the slab allocators Thread-Index: AQHZZH7yC1nc5Yxd6ES5VUUdsjQvja8WxpGg Date: Sat, 1 Apr 2023 18:33:28 +0000 Message-ID: References: <20230401094658.11146-1-vbabka@suse.cz> In-Reply-To: <20230401094658.11146-1-vbabka@suse.cz> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: zfgswe5gtchtph17cyq3rzfwsjcn5s3k X-Rspam-User: X-Rspamd-Queue-Id: 4A2F9A0007 X-Rspamd-Server: rspam06 X-HE-Tag: 1680374013-921409 X-HE-Meta: U2FsdGVkX1/qhKRuWdd6HmxqwWXfT+pp+CZsGp3taGPj53a/+n0jVKfKPwQEtNlcKLaUy0pxTiGHKceZbr6H8VZHfpYJRTymYrotWnjz4czRg7DtpqBIy3QupWf4EBZbfG1lZSdMkKqKyclFRVHDTReAbihl1DrGU8M7THkV08cvpEAqFgPphq/6FlT527wKexWeVftDlUwDFqxLDwoL014eBdxDBRzbTg0FzQbJUdJmpwACcygaXixDUPHWR6OF2yR1ql9chiN0oD5KbIoOgLyEjPA3w8bYISATCal/CT4vUBYgw2y7rvccy6/VAsG1drbxQsoERyPGqlWp2CRwDjXRa+fCREF26t3vjtngaJrnxDIeptilCbTgoJOjyQUSjU5gqxBgPlBl8g4hBmCI2RL9pJFW2Ef5iUdgI2vTLhvo6bv3Vq9ouB4s8Sc+yRveJqvwOxdzIu0GoC3NnpononNLcZkJROAoV0hozlcax9lrwpE+18d0V5++3qUJpN5pLPIF1NT2ldAjoZTp5CtDZlAjkimwUYy6P0GLnu4HoVbJLaWVfnrj83H3sLm7EFwVY1/qjtz6mznKUIDJyHdAbMnXlAsFqmsyM1wjdO4w9y0PEyC09QQcRQS1brNDJF8OYse8Oka/9TwnXgry9gCArp2UdtME6tveTeDk/DiLY3Auxz9N8vFt3ixBP3KAJvWDjHASQA+2zZ+FG+WdJbVpABW8vskjU3ZWZb5w1mI0nEfJV/1T9dqPB7H8QIBsls+mITz/Pw16WnzAzU5hnl2Zs6q3iV9y1h1nhXS0PdSuF+KtDUnUlxnfYK2jCL4c3/NhK9bmFATkDiQ1x96/vKSkQNQeVMIEZz5dPGb4BceUSnbasL32XNPYGZpaeyU0XqtqxeyVZTue76EwZNGgCuqmzFb14R/m9mYfaixNpoQvyyctsw2KH6Dci6EigYYo/CJyDjisz9H88jtBqXb3xmT Zch93x6r 5wzJFLbwKrzwaccMOOOn/peH7RQF947ozPfucPdF13YsKPm/6WLM3XZcd5zeFIaILVfQNA3vw2BP/o2ID99ERN5+cYst5P3OVznXv0EatRKKQ/L81nlr3Mpeof1yQ/PBKICybRgwp0f3Be479m7LxNIVqRJn8yMdkCwsInJ/Ink5d6eCUXBCAV3Rx5aamJJD50cbl6s1zlB+SEqi3PMOrNQx5NFD8iYmcRiHRdjxRGyE4eb8EE1UbpVeK8A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.002620, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Vlastimil Babka > Sent: 32 March 2023 10:47 >=20 > As the SLOB removal is on track and the SLAB removal is planned, I have > realized - why should we stop there and not remove also SLUB? What's a > slab allocator good for in 2023? The RAM sizes are getting larger and > the modules cheaper [1]. The object constructor trick was perhaps > interesting in 1994, but not with contemporary CPUs. So all the slab > allocator does today is just adding an unnecessary layer of complexity > over the page allocator. Why stop there? Remove kmalloc() completely. With cheap memory isn't unreasonable to go back to compile-time settable fixed size arrays for all items. Should make 'use after free' much easier to track down. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)