The kcompactd threads are affined to housekeeping CPUs (HK_TYPE_DOMAIN) at boot to avoid interference with isolated workloads. Currently, these threads do not migrate when the housekeeping boundaries are reconfigured at runtime.
Implement a housekeeping notifier to synchronize kcompactd affinity. This ensures that background compaction threads honor the dynamic isolation boundaries configured via the DHEI sysfs interface. Signed-off-by: Qiliang Yuan <[email protected]> --- mm/compaction.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/mm/compaction.c b/mm/compaction.c index 1e8f8eca318c6..574ee3c6dc942 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -24,6 +24,7 @@ #include <linux/page_owner.h> #include <linux/psi.h> #include <linux/cpuset.h> +#include <linux/sched/isolation.h> #include "internal.h" #ifdef CONFIG_COMPACTION @@ -3246,6 +3247,7 @@ void __meminit kcompactd_run(int nid) pr_err("Failed to start kcompactd on node %d\n", nid); pgdat->kcompactd = NULL; } else { + housekeeping_affine(pgdat->kcompactd, HK_TYPE_KTHREAD); wake_up_process(pgdat->kcompactd); } } @@ -3320,6 +3322,30 @@ static const struct ctl_table vm_compaction[] = { }, }; +static int kcompactd_housekeeping_reconfigure(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct housekeeping_update *upd = data; + unsigned int type = upd->type; + + if (action == HK_UPDATE_MASK && type == HK_TYPE_KTHREAD) { + int nid; + + for_each_node_state(nid, N_MEMORY) { + pg_data_t *pgdat = NODE_DATA(nid); + + if (pgdat->kcompactd) + housekeeping_affine(pgdat->kcompactd, HK_TYPE_KTHREAD); + } + } + + return NOTIFY_OK; +} + +static struct notifier_block kcompactd_housekeeping_nb = { + .notifier_call = kcompactd_housekeeping_reconfigure, +}; + static int __init kcompactd_init(void) { int nid; @@ -3327,6 +3353,7 @@ static int __init kcompactd_init(void) for_each_node_state(nid, N_MEMORY) kcompactd_run(nid); register_sysctl_init("vm", vm_compaction); + housekeeping_register_notifier(&kcompactd_housekeeping_nb); return 0; } subsys_initcall(kcompactd_init) -- 2.43.0
