[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240916224925.20540-14-frederic@kernel.org>
Date: Tue, 17 Sep 2024 00:49:17 +0200
From: Frederic Weisbecker <frederic@...nel.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <frederic@...nel.org>,
Michal Hocko <mhocko@...nel.org>,
Vlastimil Babka <vbabka@...e.cz>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-mm@...ck.org,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 13/19] mm: Create/affine kcompactd to its preferred node
Kcompactd is dedicated to a specific node. As such it wants to be
preferrably affine to it, memory and CPUs-wise.
Use the proper kthread API to achieve that. As a bonus it takes care of
CPU-hotplug events and CPU-isolation on its behalf.
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
---
mm/compaction.c | 43 +++----------------------------------------
1 file changed, 3 insertions(+), 40 deletions(-)
diff --git a/mm/compaction.c b/mm/compaction.c
index eb95e9b435d0..69742555f2e5 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -3179,15 +3179,9 @@ void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx)
static int kcompactd(void *p)
{
pg_data_t *pgdat = (pg_data_t *)p;
- struct task_struct *tsk = current;
long default_timeout = msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC);
long timeout = default_timeout;
- const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
-
- if (!cpumask_empty(cpumask))
- set_cpus_allowed_ptr(tsk, cpumask);
-
set_freezable();
pgdat->kcompactd_max_order = 0;
@@ -3258,10 +3252,12 @@ void __meminit kcompactd_run(int nid)
if (pgdat->kcompactd)
return;
- pgdat->kcompactd = kthread_run(kcompactd, pgdat, "kcompactd%d", nid);
+ pgdat->kcompactd = kthread_create_on_node(kcompactd, pgdat, nid, "kcompactd%d", nid);
if (IS_ERR(pgdat->kcompactd)) {
pr_err("Failed to start kcompactd on node %d\n", nid);
pgdat->kcompactd = NULL;
+ } else {
+ wake_up_process(pgdat->kcompactd);
}
}
@@ -3279,30 +3275,6 @@ void __meminit kcompactd_stop(int nid)
}
}
-/*
- * It's optimal to keep kcompactd on the same CPUs as their memory, but
- * not required for correctness. So if the last cpu in a node goes
- * away, we get changed to run anywhere: as the first one comes back,
- * restore their cpu bindings.
- */
-static int kcompactd_cpu_online(unsigned int cpu)
-{
- int nid;
-
- for_each_node_state(nid, N_MEMORY) {
- pg_data_t *pgdat = NODE_DATA(nid);
- const struct cpumask *mask;
-
- mask = cpumask_of_node(pgdat->node_id);
-
- if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids)
- /* One of our CPUs online: restore mask */
- if (pgdat->kcompactd)
- set_cpus_allowed_ptr(pgdat->kcompactd, mask);
- }
- return 0;
-}
-
static int proc_dointvec_minmax_warn_RT_change(const struct ctl_table *table,
int write, void *buffer, size_t *lenp, loff_t *ppos)
{
@@ -3362,15 +3334,6 @@ static struct ctl_table vm_compaction[] = {
static int __init kcompactd_init(void)
{
int nid;
- int ret;
-
- ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
- "mm/compaction:online",
- kcompactd_cpu_online, NULL);
- if (ret < 0) {
- pr_err("kcompactd: failed to register hotplug callbacks.\n");
- return ret;
- }
for_each_node_state(nid, N_MEMORY)
kcompactd_run(nid);
--
2.46.0
Powered by blists - more mailing lists