diff options
| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2025-03-12 10:10:14 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-03-17 22:07:04 -0700 |
| commit | ca868cd77063ee670ade6d5d1554e3f5f223afd7 (patch) | |
| tree | 66594f2fad785c97014c234e9abaa07328cce4a3 /mm | |
| parent | c0ebbb3841e07c4493e6fe351698806b09a87a37 (diff) | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/vmscan.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index bbd3913e3887..2bc740637a6c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -7577,7 +7577,7 @@ int node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order) if (node_state(pgdat->node_id, N_CPU) && pgdat->node_id != numa_node_id()) return NODE_RECLAIM_NOSCAN; - if (test_and_set_bit(PGDAT_RECLAIM_LOCKED, &pgdat->flags)) + if (test_and_set_bit_lock(PGDAT_RECLAIM_LOCKED, &pgdat->flags)) return NODE_RECLAIM_NOSCAN; ret = __node_reclaim(pgdat, gfp_mask, order); |