Messages in this thread | | | From | "Huang\, Ying" <> | Subject | Re: [PATCH -mm -v2 2/6] mm, swap: Add swap readahead hit statistics | Date | Wed, 12 Jul 2017 10:22:42 +0800 |
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Dave Hansen <dave.hansen@intel.com> writes:
> On 06/29/2017 06:44 PM, Huang, Ying wrote: >> >> static atomic_t swapin_readahead_hits = ATOMIC_INIT(4); >> +static atomic_long_t swapin_readahead_hits_total = ATOMIC_INIT(0); >> +static atomic_long_t swapin_readahead_total = ATOMIC_INIT(0); >> >> void show_swap_cache_info(void) >> { >> @@ -305,8 +307,10 @@ 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); >> + atomic_long_inc(&swapin_readahead_hits_total); >> + } >> } > > Adding global atomics that we touch in hot paths seems like poor > future-proofing. Are we sure we want to do this and not use some of the > nice, fancy, percpu counters that we have?
Yes. It is much better to use percpu counters instead. Will change it in the next version.
Best Regards, Huang, Ying
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