mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-23 19:07:42 -04:00
9db298a439
Patch series "Kernel stack usage histogram", v6. Provide histogram of stack sizes for the exited threads: Example outputs: Intel: $ grep kstack /proc/vmstat kstack_1k 3 kstack_2k 188 kstack_4k 11391 kstack_8k 243 kstack_16k 0 ARM with 64K page_size: $ grep kstack /proc/vmstat kstack_1k 1 kstack_2k 340 kstack_4k 25212 kstack_8k 1659 kstack_16k 0 kstack_32k 0 kstack_64k 0 This patch (of 3): At the moment the valid index for the indirection tables for memcg stats and events is < S8_MAX. These indirection tables are used in performance critical codepaths. With the latest addition to the vm_events, the NR_VM_EVENT_ITEMS has gone over S8_MAX. One way to resolve is to increase the entry size of the indirection table from int8_t to int16_t but this will increase the potential number of cachelines needed to access the indirection table. This patch took a different approach and make the valid index < U8_MAX. In this way the size of the indirection tables will remain same and we only need to invalid index check from less than 0 to equal to U8_MAX. In this approach we have also removed a subtraction from the performance critical codepaths. [pasha.tatashin@soleen.com: v6] Link: https://lkml.kernel.org/r/20240730150158.832783-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20240724203322.2765486-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20240724203322.2765486-2-pasha.tatashin@soleen.com Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev> Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Li Zhijian <lizhijian@fujitsu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.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.