Mathieu Desnoyers ca868cd770 mm: lock PGDAT_RECLAIM_LOCKED with acquire memory ordering
The PGDAT_RECLAIM_LOCKED bit is used to provide mutual exclusion of node
reclaim for struct pglist_data using a single bit.

Use test_and_set_bit_lock rather than test_and_set_bit to test-and-set
PGDAT_RECLAIM_LOCKED with an acquire memory ordering semantic.

This changes the "lock" acquisition from a full barrier to an acquire
memory ordering, which is weaker.  The acquire semi-permeable barrier
paired with the release on unlock is sufficient for this mutual exclusion
use-case.

No behavior change intended other than to reduce overhead by using the
appropriate barrier.

Link: https://lkml.kernel.org/r/20250312141014.129725-2-mathieu.desnoyers@efficios.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 22:07:04 -07:00
2024-09-01 20:43:24 -07:00
2025-02-04 11:27:45 -05:00
2022-09-28 09:02:20 +02:00
2025-03-16 22:06:01 -07:00
2025-03-09 13:45:25 -10:00
2024-03-18 03:36:32 -06:00

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.
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