From: "Huang\, Ying" <ying.huang@intel.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>,
Shaohua Li <shli@kernel.org>, Hugh Dickins <hughd@google.com>,
Fengguang Wu <fengguang.wu@intel.com>,
Tim Chen <tim.c.chen@intel.com>
Subject: Re: [PATCH -mm -v2 2/6] mm, swap: Add swap readahead hit statistics
Date: Wed, 12 Jul 2017 10:22:42 +0800 [thread overview]
Message-ID: <87shi24cnh.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <1152d4f5-fe8b-b46c-9d6b-3ecf69019172@intel.com> (Dave Hansen's message of "Tue, 11 Jul 2017 11:25:36 -0700")
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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next prev parent reply other threads:[~2017-07-12 2:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-30 1:44 [PATCH -mm -v2 0/6] mm, swap: VMA based swap readahead Huang, Ying
2017-06-30 1:44 ` [PATCH -mm -v2 1/6] mm, swap: Add swap cache statistics sysfs interface Huang, Ying
2017-06-30 1:44 ` [PATCH -mm -v2 2/6] mm, swap: Add swap readahead hit statistics Huang, Ying
2017-07-11 18:25 ` Dave Hansen
2017-07-12 2:22 ` Huang, Ying [this message]
2017-06-30 1:44 ` [PATCH -mm -v2 3/6] mm, swap: Fix swap readahead marking Huang, Ying
2017-06-30 1:44 ` [PATCH -mm -v2 4/6] mm, swap: VMA based swap readahead Huang, Ying
2017-06-30 1:44 ` [PATCH -mm -v2 5/6] mm, swap: Add sysfs interface for " Huang, Ying
2017-06-30 1:44 ` [PATCH -mm -v2 6/6] mm, swap: Don't use VMA based swap readahead if HDD is used as swap Huang, Ying
2017-06-30 2:26 ` [PATCH -mm -v2 0/6] mm, swap: VMA based swap readahead Minchan Kim
2017-06-30 7:53 ` Huang, Ying
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