From: Frederic Weisbecker <frederic@kernel.org>
Date: Thu, 26 Sep 2024 22:49:03 +0000 (+0200)
Subject: mm: Create/affine kswapd to its preferred node
X-Git-Tag: v6.14-rc1~173^2~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c6a566f6c1b4d5dff659acd221f95a72923f4085;p=thirdparty%2Flinux.git

mm: Create/affine kswapd to its preferred node

kswapd 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@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 76378bc257e38..ec4eab23fb191 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -7182,10 +7182,6 @@ static int kswapd(void *p)
 	unsigned int highest_zoneidx = MAX_NR_ZONES - 1;
 	pg_data_t *pgdat = (pg_data_t *)p;
 	struct task_struct *tsk = current;
-	const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
-
-	if (!cpumask_empty(cpumask))
-		set_cpus_allowed_ptr(tsk, cpumask);
 
 	/*
 	 * Tell the memory management that we're a "memory allocator",
@@ -7354,13 +7350,15 @@ void __meminit kswapd_run(int nid)
 
 	pgdat_kswapd_lock(pgdat);
 	if (!pgdat->kswapd) {
-		pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid);
+		pgdat->kswapd = kthread_create_on_node(kswapd, pgdat, nid, "kswapd%d", nid);
 		if (IS_ERR(pgdat->kswapd)) {
 			/* failure at boot is fatal */
 			pr_err("Failed to start kswapd on node %d，ret=%ld\n",
 				   nid, PTR_ERR(pgdat->kswapd));
 			BUG_ON(system_state < SYSTEM_RUNNING);
 			pgdat->kswapd = NULL;
+		} else {
+			wake_up_process(pgdat->kswapd);
 		}
 	}
 	pgdat_kswapd_unlock(pgdat);