On Thu, Apr 21, 2011 at 10:11 PM, KOSAKI Motohiro < kosaki.motohiro@jp.fujitsu.com> wrote: > > Add the kswapd_mem field in kswapd descriptor which links the kswapd > > kernel thread to a memcg. The per-memcg kswapd is sleeping in the wait > > queue headed at kswapd_wait field of the kswapd descriptor. > > > > The kswapd() function is now shared between global and per-memcg kswapd. > It > > is passed in with the kswapd descriptor which contains the information of > > either node or memcg. Then the new function balance_mem_cgroup_pgdat is > > invoked if it is per-mem kswapd thread, and the implementation of the > function > > is on the following patch. > > > > change v7..v6: > > 1. change the threading model of memcg from per-memcg-per-thread to > thread-pool. > > this is based on the patch from KAMAZAWA. > > > > change v6..v5: > > 1. rename is_node_kswapd to is_global_kswapd to match the > scanning_global_lru. > > 2. revert the sleeping_prematurely change, but keep the > kswapd_try_to_sleep() > > for memcg. > > > > changelog v4..v3: > > 1. fix up the kswapd_run and kswapd_stop for online_pages() and > offline_pages. > > 2. drop the PF_MEMALLOC flag for memcg kswapd for now per KAMAZAWA's > request. > > > > changelog v3..v2: > > 1. split off from the initial patch which includes all changes of the > following > > three patches. > > > > Signed-off-by: Ying Han > > Signed-off-by: KAMEZAWA Hiroyuki > > Looks ok. but this one have some ugly coding style. > > functioon() > { > if (is_global_kswapd()) { > looooooooong lines > ... > .. > } else { > another looooooong lines > ... > .. > } > } > > please pay attention more to keep simpler code. > However, I don't think this patch has major issue. I expect I can ack next > version. > > > Thank you for reviewing. > > > --- > > include/linux/swap.h | 2 +- > > mm/memory_hotplug.c | 2 +- > > mm/vmscan.c | 156 > +++++++++++++++++++++++++++++++------------------- > > 3 files changed, 100 insertions(+), 60 deletions(-) > > > > diff --git a/include/linux/swap.h b/include/linux/swap.h > > index 9b91ca4..a062f0b 100644 > > --- a/include/linux/swap.h > > +++ b/include/linux/swap.h > > @@ -303,7 +303,7 @@ static inline void > scan_unevictable_unregister_node(struct node *node) > > } > > #endif > > > > -extern int kswapd_run(int nid); > > +extern int kswapd_run(int nid, int id); > > "id" is bad name. there is no information. please use memcg-id or so on. > will change . > > > > extern void kswapd_stop(int nid); > > > > #ifdef CONFIG_MMU > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > > index 321fc74..36b4eed 100644 > > --- a/mm/memory_hotplug.c > > +++ b/mm/memory_hotplug.c > > @@ -462,7 +462,7 @@ int online_pages(unsigned long pfn, unsigned long > nr_pages) > > setup_per_zone_wmarks(); > > calculate_zone_inactive_ratio(zone); > > if (onlined_pages) { > > - kswapd_run(zone_to_nid(zone)); > > + kswapd_run(zone_to_nid(zone), 0); > > node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); > > } > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 7aba681..63c557e 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -2241,6 +2241,8 @@ static bool pgdat_balanced(pg_data_t *pgdat, > unsigned long balanced_pages, > > return balanced_pages > (present_pages >> 2); > > } > > > > +#define is_global_kswapd(kswapd_p) ((kswapd_p)->kswapd_pgdat) > > please use inline function. > Hmm. see will change next/ > > > > > + > > /* is kswapd sleeping prematurely? */ > > static bool sleeping_prematurely(pg_data_t *pgdat, int order, long > remaining, > > int classzone_idx) > > @@ -2583,40 +2585,46 @@ static void kswapd_try_to_sleep(struct kswapd > *kswapd_p, int order, > > > > prepare_to_wait(wait_h, &wait, TASK_INTERRUPTIBLE); > > > > - /* Try to sleep for a short interval */ > > - if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) > { > > - remaining = schedule_timeout(HZ/10); > > - finish_wait(wait_h, &wait); > > - prepare_to_wait(wait_h, &wait, TASK_INTERRUPTIBLE); > > - } > > - > > - /* > > - * After a short sleep, check if it was a premature sleep. If not, > then > > - * go fully to sleep until explicitly woken up. > > - */ > > - if (!sleeping_prematurely(pgdat, order, remaining, classzone_idx)) > { > > - trace_mm_vmscan_kswapd_sleep(pgdat->node_id); > > + if (is_global_kswapd(kswapd_p)) { > > bad indentation. :-/ > please don't increase coding mess. > > if (!is_global_kswapd(kswapd_p)) { > kswapd_try_to_sleep_memcg(); > return; > } > > is simpler. > > Ok. I will check on next post. > > > + /* Try to sleep for a short interval */ > > + if (!sleeping_prematurely(pgdat, order, > > + remaining, classzone_idx)) { > > + remaining = schedule_timeout(HZ/10); > > + finish_wait(wait_h, &wait); > > + prepare_to_wait(wait_h, &wait, TASK_INTERRUPTIBLE); > > + } > > > > /* > > - * vmstat counters are not perfectly accurate and the > estimated > > - * value for counters such as NR_FREE_PAGES can deviate > from the > > - * true value by nr_online_cpus * threshold. To avoid the > zone > > - * watermarks being breached while under pressure, we > reduce the > > - * per-cpu vmstat threshold while kswapd is awake and > restore > > - * them before going back to sleep. > > + * After a short sleep, check if it was a premature sleep. > > + * If not, then go fully to sleep until explicitly woken > up. > > */ > > - set_pgdat_percpu_threshold(pgdat, > calculate_normal_threshold); > > - schedule(); > > - set_pgdat_percpu_threshold(pgdat, > calculate_pressure_threshold); > > + if (!sleeping_prematurely(pgdat, order, > > + remaining, classzone_idx)) { > > + trace_mm_vmscan_kswapd_sleep(pgdat->node_id); > > + set_pgdat_percpu_threshold(pgdat, > > + calculate_normal_threshold); > > + schedule(); > > + set_pgdat_percpu_threshold(pgdat, > > + calculate_pressure_threshold); > > + } else { > > + if (remaining) > > + > count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); > > + else > > + > count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); > > + } > > } else { > > - if (remaining) > > - count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); > > - else > > - count_vm_event(KSWAPD_HIGH_WMARK_HIT_QUICKLY); > > + /* For now, we just check the remaining works.*/ > > + if (mem_cgroup_kswapd_can_sleep()) > > + schedule(); > > } > > finish_wait(wait_h, &wait); > > > > } > > > > +static unsigned long shrink_mem_cgroup(struct mem_cgroup *mem_cont, int > order) > > +{ > > + return 0; > > +} > > + > > /* > > * The background pageout daemon, started as a kernel thread > > * from the init process. > > @@ -2636,6 +2644,7 @@ int kswapd(void *p) > > int classzone_idx; > > struct kswapd *kswapd_p = (struct kswapd *)p; > > pg_data_t *pgdat = kswapd_p->kswapd_pgdat; > > + struct mem_cgroup *mem; > > struct task_struct *tsk = current; > > > > struct reclaim_state reclaim_state = { > > @@ -2645,9 +2654,11 @@ int kswapd(void *p) > > > > lockdep_set_current_reclaim_state(GFP_KERNEL); > > > > - cpumask = cpumask_of_node(pgdat->node_id); > > - if (!cpumask_empty(cpumask)) > > - set_cpus_allowed_ptr(tsk, cpumask); > > + if (is_global_kswapd(kswapd_p)) { > > + cpumask = cpumask_of_node(pgdat->node_id); > > + if (!cpumask_empty(cpumask)) > > + set_cpus_allowed_ptr(tsk, cpumask); > > + } > > current->reclaim_state = &reclaim_state; > > > > /* > > @@ -2662,7 +2673,10 @@ int kswapd(void *p) > > * us from recursively trying to free more memory as we're > > * trying to free the first piece of memory in the first place). > > */ > > - tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; > > + if (is_global_kswapd(kswapd_p)) > > + tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; > > + else > > + tsk->flags |= PF_SWAPWRITE | PF_KSWAPD; > > set_freezable(); > > > > order = 0; > > @@ -2672,36 +2686,48 @@ int kswapd(void *p) > > int new_classzone_idx; > > int ret; > > > > - new_order = pgdat->kswapd_max_order; > > - new_classzone_idx = pgdat->classzone_idx; > > - pgdat->kswapd_max_order = 0; > > - pgdat->classzone_idx = MAX_NR_ZONES - 1; > > - if (order < new_order || classzone_idx > new_classzone_idx) > { > > - /* > > - * Don't sleep if someone wants a larger 'order' > > - * allocation or has tigher zone constraints > > - */ > > - order = new_order; > > - classzone_idx = new_classzone_idx; > > - } else { > > - kswapd_try_to_sleep(kswapd_p, order, > classzone_idx); > > - order = pgdat->kswapd_max_order; > > - classzone_idx = pgdat->classzone_idx; > > + if (is_global_kswapd(kswapd_p)) { > > + new_order = pgdat->kswapd_max_order; > > + new_classzone_idx = pgdat->classzone_idx; > > pgdat->kswapd_max_order = 0; > > pgdat->classzone_idx = MAX_NR_ZONES - 1; > > - } > > + if (order < new_order || > > + classzone_idx > new_classzone_idx) > { > > + /* > > + * Don't sleep if someone wants a larger > 'order' > > + * allocation or has tigher zone > constraints > > + */ > > + order = new_order; > > + classzone_idx = new_classzone_idx; > > + } else { > > + kswapd_try_to_sleep(kswapd_p, order, > > + classzone_idx); > > + order = pgdat->kswapd_max_order; > > + classzone_idx = pgdat->classzone_idx; > > + pgdat->kswapd_max_order = 0; > > + pgdat->classzone_idx = MAX_NR_ZONES - 1; > > -ETOODEEPNEST. > > > > + } > > + } else > > + kswapd_try_to_sleep(kswapd_p, order, > classzone_idx); > > > > ret = try_to_freeze(); > > if (kthread_should_stop()) > > break; > > > > + if (ret) > > + continue; > > /* > > * We can speed up thawing tasks if we don't call > balance_pgdat > > * after returning from the refrigerator > > */ > > - if (!ret) { > > + if (is_global_kswapd(kswapd_p)) { > > trace_mm_vmscan_kswapd_wake(pgdat->node_id, order); > > order = balance_pgdat(pgdat, order, > &classzone_idx); > > + } else { > > + mem = mem_cgroup_get_shrink_target(); > > + if (mem) > > + shrink_mem_cgroup(mem, order); > > + mem_cgroup_put_shrink_target(mem); > > } > > > > > } > > return 0; > > @@ -2845,30 +2871,44 @@ static int __devinit cpu_callback(struct > notifier_block *nfb, > > * This kswapd start function will be called by init and node-hot-add. > > * On node-hot-add, kswapd will moved to proper cpus if cpus are > hot-added. > > */ > > -int kswapd_run(int nid) > > +int kswapd_run(int nid, int memcgid) > > { > > - pg_data_t *pgdat = NODE_DATA(nid); > > struct task_struct *kswapd_tsk; > > + pg_data_t *pgdat = NULL; > > struct kswapd *kswapd_p; > > + static char name[TASK_COMM_LEN]; > > int ret = 0; > > > > - if (pgdat->kswapd) > > - return 0; > > + if (!memcgid) { > > + pgdat = NODE_DATA(nid); > > + if (pgdat->kswapd) > > + return ret; > > + } > > > > kswapd_p = kzalloc(sizeof(struct kswapd), GFP_KERNEL); > > if (!kswapd_p) > > return -ENOMEM; > > > > - pgdat->kswapd = kswapd_p; > > - kswapd_p->kswapd_wait = &pgdat->kswapd_wait; > > - kswapd_p->kswapd_pgdat = pgdat; > > + if (!memcgid) { > > + pgdat->kswapd = kswapd_p; > > + kswapd_p->kswapd_wait = &pgdat->kswapd_wait; > > + kswapd_p->kswapd_pgdat = pgdat; > > + snprintf(name, TASK_COMM_LEN, "kswapd_%d", nid); > > + } else { > > + kswapd_p->kswapd_wait = mem_cgroup_kswapd_waitq(); > > + snprintf(name, TASK_COMM_LEN, "memcg_%d", memcgid); > > + } > > > > - kswapd_tsk = kthread_run(kswapd, kswapd_p, "kswapd%d", nid); > > You seems to change kswapd name slightly. > > > > > + kswapd_tsk = kthread_run(kswapd, kswapd_p, name); > > if (IS_ERR(kswapd_tsk)) { > > /* failure at boot is fatal */ > > BUG_ON(system_state == SYSTEM_BOOTING); > > - printk("Failed to start kswapd on node %d\n",nid); > > - pgdat->kswapd = NULL; > > + if (!memcgid) { > > + printk(KERN_ERR "Failed to start kswapd on node > %d\n", > > + nid); > > + pgdat->kswapd = NULL; > > + } else > > + printk(KERN_ERR "Failed to start kswapd on > memcg\n"); > > Why don't you show memcg-id here? > will change. > > > > kfree(kswapd_p); > > ret = -1; > > } else > > @@ -2899,7 +2939,7 @@ static int __init kswapd_init(void) > > > > swap_setup(); > > for_each_node_state(nid, N_HIGH_MEMORY) > > - kswapd_run(nid); > > + kswapd_run(nid, 0); > > hotcpu_notifier(cpu_callback, 0); > > return 0; > > } > > -- > > 1.7.3.1 > > > > > >