On 7/26/24 11:56 PM, Frederic Weisbecker wrote:
> Now that kthreads have an infrastructure to handle preferred affinity
> against CPU hotplug and housekeeping cpumask, convert kswapd to use
> it instead of handling halfway all the constraints by itself.
>
> Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/vmscan.c | 8 +++-----
> 1 file changed, 3 insertions(+), 5 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 2e34de9cd0d4..94359a893b4f 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -7116,10 +7116,6 @@ 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",
> @@ -7288,7 +7284,7 @@ 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(kswapd, pgdat, "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",
> @@ -7296,6 +7292,8 @@ void __meminit kswapd_run(int nid)
> BUG_ON(system_state < SYSTEM_RUNNING);
> pgdat->kswapd = NULL;
> }
> + kthread_affine_preferred(pgdat->kswapd, cpumask_of_node(pgdat->node_id));
> + wake_up_process(pgdat->kswapd);
> }
> pgdat_kswapd_unlock(pgdat);
> }