| Message ID | 20240916224925.20540-14-frederic@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On Tue 17-09-24 00:49:17, Frederic Weisbecker wrote: > 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@suse.cz> > Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Clear simplification, thanks! > --- > 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
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);