Re: [PATCH -mm -v4 1/5] mm, swap: Add swap readahead hit statistics
Andrew Morton writes: > On Mon, 7 Aug 2017 13:40:34 +0800 "Huang, Ying" wrote: > >> From: Huang Ying >> >> The statistics for total readahead pages and total readahead hits are >> recorded and exported via the following sysfs interface. >> >> /sys/kernel/mm/swap/ra_hits >> /sys/kernel/mm/swap/ra_total >> >> With them, the efficiency of the swap readahead could be measured, so >> that the swap readahead algorithm and parameters could be tuned >> accordingly. >> >> ... >> >> --- a/include/linux/vm_event_item.h >> +++ b/include/linux/vm_event_item.h >> @@ -106,6 +106,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, >> VMACACHE_FIND_HITS, >> VMACACHE_FULL_FLUSHES, >> #endif >> +SWAP_RA, >> +SWAP_RA_HIT, >> NR_VM_EVENT_ITEMS >> }; > > swap_state.o isn't even compiled if CONFIG_SWAP=n so there doesn't seem > much point in displaying these? Oh, Yes! Thanks for pointing this out. Best Regards, Huang, Ying > --- > a/include/linux/vm_event_item.h~mm-swap-add-swap-readahead-hit-statistics-fix > +++ a/include/linux/vm_event_item.h > @@ -106,8 +106,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS > VMACACHE_FIND_HITS, > VMACACHE_FULL_FLUSHES, > #endif > +#ifdef CONFIG_SWAP > SWAP_RA, > SWAP_RA_HIT, > +#endif > NR_VM_EVENT_ITEMS > }; > > --- a/mm/vmstat.c~mm-swap-add-swap-readahead-hit-statistics-fix > +++ a/mm/vmstat.c > @@ -1098,9 +1098,10 @@ const char * const vmstat_text[] = { > "vmacache_find_hits", > "vmacache_full_flushes", > #endif > - > +#ifdef CONFIG_SWAP > "swap_ra", > "swap_ra_hit", > +#endif > #endif /* CONFIG_VM_EVENTS_COUNTERS */ > }; > #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */ > _
Re: [PATCH -mm -v4 1/5] mm, swap: Add swap readahead hit statistics
On Mon, 7 Aug 2017 13:40:34 +0800 "Huang, Ying" wrote: > From: Huang Ying > > The statistics for total readahead pages and total readahead hits are > recorded and exported via the following sysfs interface. > > /sys/kernel/mm/swap/ra_hits > /sys/kernel/mm/swap/ra_total > > With them, the efficiency of the swap readahead could be measured, so > that the swap readahead algorithm and parameters could be tuned > accordingly. > > ... > > --- a/include/linux/vm_event_item.h > +++ b/include/linux/vm_event_item.h > @@ -106,6 +106,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, > VMACACHE_FIND_HITS, > VMACACHE_FULL_FLUSHES, > #endif > + SWAP_RA, > + SWAP_RA_HIT, > NR_VM_EVENT_ITEMS > }; swap_state.o isn't even compiled if CONFIG_SWAP=n so there doesn't seem much point in displaying these? --- a/include/linux/vm_event_item.h~mm-swap-add-swap-readahead-hit-statistics-fix +++ a/include/linux/vm_event_item.h @@ -106,8 +106,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PS VMACACHE_FIND_HITS, VMACACHE_FULL_FLUSHES, #endif +#ifdef CONFIG_SWAP SWAP_RA, SWAP_RA_HIT, +#endif NR_VM_EVENT_ITEMS }; --- a/mm/vmstat.c~mm-swap-add-swap-readahead-hit-statistics-fix +++ a/mm/vmstat.c @@ -1098,9 +1098,10 @@ const char * const vmstat_text[] = { "vmacache_find_hits", "vmacache_full_flushes", #endif - +#ifdef CONFIG_SWAP "swap_ra", "swap_ra_hit", +#endif #endif /* CONFIG_VM_EVENTS_COUNTERS */ }; #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */ _
[PATCH -mm -v4 1/5] mm, swap: Add swap readahead hit statistics
From: Huang Ying The statistics for total readahead pages and total readahead hits are recorded and exported via the following sysfs interface. /sys/kernel/mm/swap/ra_hits /sys/kernel/mm/swap/ra_total With them, the efficiency of the swap readahead could be measured, so that the swap readahead algorithm and parameters could be tuned accordingly. Signed-off-by: "Huang, Ying" Cc: Johannes Weiner Cc: Minchan Kim Cc: Rik van Riel Cc: Shaohua Li Cc: Hugh Dickins Cc: Fengguang Wu Cc: Tim Chen Cc: Dave Hansen --- include/linux/vm_event_item.h | 2 ++ mm/swap_state.c | 9 +++-- mm/vmstat.c | 3 +++ 3 files changed, 12 insertions(+), 2 deletions(-) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index e02820fc2861..27e3339cfd65 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -106,6 +106,8 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, VMACACHE_FIND_HITS, VMACACHE_FULL_FLUSHES, #endif + SWAP_RA, + SWAP_RA_HIT, NR_VM_EVENT_ITEMS }; diff --git a/mm/swap_state.c b/mm/swap_state.c index b68c93014f50..d1bdb31cab13 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -305,8 +305,10 @@ struct page * lookup_swap_cache(swp_entry_t entry) if (page && likely(!PageTransCompound(page))) { INC_CACHE_INFO(find_success); - if (TestClearPageReadahead(page)) + if (TestClearPageReadahead(page)) { atomic_inc(&swapin_readahead_hits); + count_vm_event(SWAP_RA_HIT); + } } INC_CACHE_INFO(find_total); @@ -516,8 +518,11 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, gfp_mask, vma, addr, false); if (!page) continue; - if (offset != entry_offset && likely(!PageTransCompound(page))) + if (offset != entry_offset && + likely(!PageTransCompound(page))) { SetPageReadahead(page); + count_vm_event(SWAP_RA); + } put_page(page); } blk_finish_plug(&plug); diff --git a/mm/vmstat.c b/mm/vmstat.c index ba9b202e8500..4c2121a8b877 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1095,6 +1095,9 @@ const char * const vmstat_text[] = { "vmacache_find_hits", "vmacache_full_flushes", #endif + + "swap_ra", + "swap_ra_hit", #endif /* CONFIG_VM_EVENTS_COUNTERS */ }; #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */ -- 2.11.0