Re: [LKP] Re: [mm] e6e88712e4: stress-ng.tmpfs.ops_per_sec -69.7% regression

[Xing Zhengjun <zhengjun.xing@linux.intel.com>]

On 11/7/2020 4:55 AM, Matthew Wilcox wrote:
> On Mon, Nov 02, 2020 at 01:21:39PM +0800, Rong Chen wrote:
>> we compared the tmpfs.ops_per_sec: (363 / 103.02) between this commit and
>> parent commit.
> 
> Thanks!  I see about a 50% hit on my system, and this patch restores the
> performance.  Can you verify this works for you?
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 9b065d412e5f..e602333f8c0d 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -225,7 +225,7 @@ static void force_shm_swapin_readahead(struct vm_area_struct *vma,
>   		struct address_space *mapping)
>   {
>   	XA_STATE(xas, &mapping->i_pages, linear_page_index(vma, start));
> -	pgoff_t end_index = end / PAGE_SIZE;
> +	pgoff_t end_index = linear_page_index(vma, end + PAGE_SIZE - 1);
>   	struct page *page;
>   
>   	rcu_read_lock();
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> 
I test the patch, the regression is disappeared.

=========================================================================================
tbox_group/testcase/rootfs/kconfig/compiler/nr_threads/disk/testtime/class/cpufreq_governor/ucode:
 
lkp-csl-2sp3/stress-ng/debian-10.4-x86_64-20200603.cgz/x86_64-rhel-8.3/gcc-9/100%/1HDD/100s/memory/performance/0x400002c

commit:
   f5df8635c5a3c912919c91be64aa198554b0f9ed
   e6e88712e43b7942df451508aafc2f083266f56b
   6bc25f0c5e0d55145f7ef087adea2693802a80f3 (this test patch)

f5df8635c5a3c912 e6e88712e43b7942df451508aaf 6bc25f0c5e0d55145f7ef087ade
---------------- --------------------------- ---------------------------
          %stddev     %change         %stddev     %change         %stddev
              \          |                \          |                \
       1198 ±  4%     -69.7%     362.67            +3.3%       1238 ± 
3%  stress-ng.tmpfs.ops
      11.62 ±  4%     -69.7%       3.52            +3.4%      12.02 ± 
3%  stress-ng.tmpfs.ops_per_sec



-- 
Zhengjun Xing