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charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: B2C1D12000B X-Stat-Signature: zbo4hsfzr8zo1jrmbwopdntxmpxo3hrk X-Rspam-User: X-HE-Tag: 1680412184-57731 X-HE-Meta: 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 wAnOnj7v UjEspSvfcHAjdah8P3vXw6kaVGKISZJ/CddeIGFmqL5+gfOXvIlxX6DTye6VdP87iYdBdvmiKFizvPdJqR69Gb3npA3cKN7PTfegGnDCZFNpq4omGPzVe2glATaVXSISRujwPUrWT6qK67Ts1aHT62n5PXi9PHh00FE0snRGV3hTfDEa07ncWPH7m91ocdB10qUF1KUb1h5jeMgcnIJN/wp65K9CBm//q2JtbkbZLQnxZ0Y9PnW+ynJtTcvyEpUecJ2SbOp46wAW8tNXLtnccNMvVSIUIpIZxbSXrWAgrRI7uYeuO6irVmhc4kks8NxH2eHaEUkXK4UIUSvp6aQLKHHZ6JA9i3jPwyEWIUr42q06U6MN/drflXMRaOYnwDcEWztlAxMqqDBmXi0t6j8PASLfAA61WgSAAw4QeF3dEBwgEtJjK6QTYQX+p32lYe2ufjCw1 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000009, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sat, Apr 1, 2023 at 5:47=E2=80=AFPM Vlastimil Babka wro= te: > > 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. > > Thus, with this patch, all three slab allocators are removed, and only a > layer that passes everything to the page allocator remains in the slab.h > and mm/slab_common.c files. This will allow users to gradually > transition away and use the page allocator directly. To summarize the > advantages: > > - Less code to maintain: over 13k lines are removed by this patch, and > more could be removed if I wast^Wspent more time on this, and later as > users are transitioned from the legacy layer. This no longer needs a > separate subsystem so remove it from MAINTAINERS (I hope I can keep the > kernel.org account anyway, though). > > - Simplified MEMCG_KMEM accounting: while I was lazy and just marked it > BROKEN in this patch, it should be trivial to use the page memcg > accounting now that we use the page allocator. The per-object > accounting went through several iterations in the past and was always > complex and added overhead. Page accounting is much simpler by > comparison. > > - Simplified KASAN and friends: also was lazy in this patch so they > can't be enabled but should be easy to fix up and work just on the > page level. > > - Simpler debugging: just use debug_pagealloc=3Don, no need to look up th= e > exact syntax of the absurdly complex slub_debug parameter. This really simplifies the complexity of dealing with memory problems in the production environment, and I hope it can be merged into the linux kernel soon. Acked-by: Jeff Xie --=20 Thanks, JeffXie