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Christian Brauner <brauner@kernel.org> says: When a kmem cache is created with SLAB_TYPESAFE_BY_RCU the free pointer must be located outside of the object because we don't know what part of the memory can safely be overwritten as it may be needed to prevent object recycling. That has the consequence that SLAB_TYPESAFE_BY_RCU may end up adding a new cacheline. This is the case for e.g., struct file. After having it shrunk down by 40 bytes and having it fit in three cachelines we still have SLAB_TYPESAFE_BY_RCU adding a fourth cacheline because it needs to accommodate the free pointer. Add a new kmem_cache_create_rcu() function that allows the caller to specify an offset where the free pointer is supposed to be placed. Before this series cat /proc/slabinfo: filp 1198 1248 256 32 2 : tunables 0 0 0 : slabdata 39 39 0 ^^^ After this series cat /proc/slabinfo: filp 1323 1323 192 21 1 : tunables 0 0 0 : slabdata 63 63 0 ^^^ * patches from https://lore.kernel.org/r/20240828-work-kmem_cache-rcu-v3-0-5460bc1f09f6@kernel.org: fs: use kmem_cache_create_rcu() mm: add kmem_cache_create_rcu() mm: remove unused root_cache argument Link: https://lore.kernel.org/r/20240828-work-kmem_cache-rcu-v3-0-5460bc1f09f6@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.