On Sat 10-05-14 08:52:17, Fabian Frederick wrote: > This patch addresses TODO featuring in original version :
This is the 3rd version of the patch and I still fail to see the motivation other than addressing a TODO which doesn't sound like a sufficient justification to me. Why is the new scheme needed in the first place? Why is calculate_normal_threshold a proper scheme? > "Make the window size depend on machine size, as we do for vmstat" > > It initializes vmpressure_win in vmstat using calculate_normal_threshold() > based on each zone/cpu * SWAP_CLUSTER_SIZE instead of > static SWAP_CLUSTER_MAX * 16 = 512 > > Some values : > > CPU MB VMPRESSURE > 8 512 1024 > 1 1024 320 > 2 1024 640 > 2 2048 768 > 4 2048 1152 > 1 4096 640 > 4 4096 1920 > ... > > (No maximum vmpressure value currently defined) > > cf mm/vmstat.c: calculate_normal_threshold for further values > > vmpressure_win is refreshed through cpu notifier and exposed read-only in > /proc/sys/vm/vmpressure_win > > Cc: Tejun Heo <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Davidlohr Bueso <[email protected]> > Cc: Li Zefan <[email protected]> > Cc: [email protected] > Signed-off-by: Fabian Frederick <[email protected]> > --- > V3: > -Further description > -sysctl handler / ulong > -Cc list > > V2: Suggestions by Andrew Morton > -Expose vmpressure_win > -Remove spinlock > > include/linux/swap.h | 4 ++++ > kernel/sysctl.c | 9 +++++++++ > mm/vmpressure.c | 4 +--- > mm/vmstat.c | 6 ++++++ > 4 files changed, 20 insertions(+), 3 deletions(-) > > diff --git a/include/linux/swap.h b/include/linux/swap.h > index 3507115..886897d 100644 > --- a/include/linux/swap.h > +++ b/include/linux/swap.h > @@ -354,6 +354,10 @@ extern int vm_swappiness; > extern int remove_mapping(struct address_space *mapping, struct page *page); > extern unsigned long vm_total_pages; > > +#ifdef CONFIG_MEMCG > +extern unsigned long vmpressure_win; > +#endif > + > #ifdef CONFIG_NUMA > extern int zone_reclaim_mode; > extern int sysctl_min_unmapped_ratio; > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 74f5b58..c0c5ea6 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1202,6 +1202,15 @@ static struct ctl_table vm_table[] = { > .mode = 0444 /* read-only */, > .proc_handler = pdflush_proc_obsolete, > }, > +#ifdef CONFIG_MEMCG > + { > + .procname = "vmpressure_window", > + .data = &vmpressure_win, > + .maxlen = sizeof(vmpressure_win), > + .mode = 0444, > + .proc_handler = proc_doulongvec_minmax, > + }, > +#endif > { > .procname = "swappiness", > .data = &vm_swappiness, > diff --git a/mm/vmpressure.c b/mm/vmpressure.c > index d4042e7..d738670 100644 > --- a/mm/vmpressure.c > +++ b/mm/vmpressure.c > @@ -35,10 +35,8 @@ > * As the vmscan reclaimer logic works with chunks which are multiple of > * SWAP_CLUSTER_MAX, it makes sense to use it for the window size as well. > * > - * TODO: Make the window size depend on machine size, as we do for vmstat > - * thresholds. Currently we set it to 512 pages (2MB for 4KB pages). > */ > -static const unsigned long vmpressure_win = SWAP_CLUSTER_MAX * 16; > +unsigned long vmpressure_win = SWAP_CLUSTER_MAX * 16; > > /* > * These thresholds are used when we account memory pressure through > diff --git a/mm/vmstat.c b/mm/vmstat.c > index 302dd07..ede68fd 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -20,6 +20,7 @@ > #include <linux/writeback.h> > #include <linux/compaction.h> > #include <linux/mm_inline.h> > +#include <linux/swap.h> > > #include "internal.h" > > @@ -163,11 +164,13 @@ void refresh_zone_stat_thresholds(void) > struct zone *zone; > int cpu; > int threshold; > + unsigned long new_vmpressure_win = 0; > > for_each_populated_zone(zone) { > unsigned long max_drift, tolerate_drift; > > threshold = calculate_normal_threshold(zone); > + new_vmpressure_win += threshold; > > for_each_online_cpu(cpu) > per_cpu_ptr(zone->pageset, cpu)->stat_threshold > @@ -184,6 +187,9 @@ void refresh_zone_stat_thresholds(void) > zone->percpu_drift_mark = high_wmark_pages(zone) + > max_drift; > } > +#ifdef CONFIG_MEMCG > + vmpressure_win = new_vmpressure_win * SWAP_CLUSTER_MAX; > +#endif > } > > void set_pgdat_percpu_threshold(pg_data_t *pgdat, > -- > 1.8.4.5 -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
