Re: [PATCH] mm: meminit: Finish initialisation of struct pages before basic setup

From: Nathan Zimmer
Date: Thu Jul 09 2015 - 13:49:18 EST


Interesting, I found a small improvement in total clock time through the area.
I tweaked page_alloc_init_late have a timer, like the deferred_init_memmap, and this patch showed a small improvement.

Ok thanks for your help.


On 07/06/2015 12:45 PM, Daniel J Blueman wrote:
Hi Nate,

On Wed, Jun 24, 2015 at 11:50 PM, Nathan Zimmer <nzimmer@xxxxxxx> wrote:
My apologies for taking so long to get back to this.

I think I did locate two potential sources of slowdown.
One is the set_cpus_allowed_ptr as I have noted previously.
However I only notice that on the very largest boxes.
I did cobble together a patch that seems to help.

The other spot I suspect is the zone lock in free_one_page.
I haven't been able to give that much thought as of yet though.

Daniel do you mind seeing if the attached patch helps out?

Just got back from travel, so apologies for the delays.

The patch doesn't mitigate the increasing initialisation time; summing the per-node times for an accurate measure, there was a total of 171.48s before the patch and 175.23s after. I double-checked and got similar data.

Thanks,
Daniel


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