]> www.infradead.org Git - users/jedix/linux-maple.git/commit
mm: lock PGDAT_RECLAIM_LOCKED with acquire memory ordering
authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Wed, 12 Mar 2025 14:10:14 +0000 (10:10 -0400)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 18 Mar 2025 05:07:04 +0000 (22:07 -0700)
commitca868cd77063ee670ade6d5d1554e3f5f223afd7
tree66594f2fad785c97014c234e9abaa07328cce4a3
parentc0ebbb3841e07c4493e6fe351698806b09a87a37
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>
mm/vmscan.c