lkml.org 
[lkml]   [2017]   [Jun]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4
On Fri, Jun 30, 2017 at 04:19:25PM -0700, Evgeny Baskakov wrote:
> Hi Jerome,
>
> It seems that the kernel can pass 0 in src_pfns for pages that it cannot
> migrate (i.e. the kernel knows that they cannot migrate prior to calling
> alloc_and_copy).
>
> So, a zero in src_pfns can mean either "the page is not allocated yet" or
> "the page cannot migrate".
>
> Can migrate_vma set the MIGRATE_PFN_MIGRATE flag for not allocated pages? On
> the driver side it is difficult to differentiate between the cases.

So this is what is happening in v24. For thing that can not be migrated you
get 0 and for things that are not allocated you get MIGRATE_PFN_MIGRATE like
the updated comments in migrate.h explain.

Cheers,
Jérôme

\
 
 \ /
  Last update: 2017-07-01 02:58    [W:0.204 / U:1.544 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site