lkml.org 
[lkml]   [2019]   [Nov]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH v1] mm/memory_hotplug: don't check the nid in find_(smallest|biggest)_section_pfn
    Date


    > Am 27.11.2019 um 20:03 schrieb Qian Cai <cai@lca.pw>:
    >
    > 
    >
    >> On Nov 27, 2019, at 12:42 PM, David Hildenbrand <david@redhat.com> wrote:
    >>
    >> Now that we always check against a zone, we can stop checking against
    >> the nid, it is implicitly covered by the zone.
    >>
    >> Cc: Andrew Morton <akpm@linux-foundation.org>
    >> Cc: Michal Hocko <mhocko@kernel.org>
    >> Cc: Oscar Salvador <osalvador@suse.de>
    >> Signed-off-by: David Hildenbrand <david@redhat.com>
    >> ---
    >> mm/memory_hotplug.c | 23 ++++++++---------------
    >> 1 file changed, 8 insertions(+), 15 deletions(-)
    >>
    >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
    >> index 46b2e056a43f..602f753c662c 100644
    >> --- a/mm/memory_hotplug.c
    >> +++ b/mm/memory_hotplug.c
    >> @@ -344,17 +344,14 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
    >> }
    >>
    >> /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
    >> -static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
    >> - unsigned long start_pfn,
    >> - unsigned long end_pfn)
    >> +static unsigned long find_smallest_section_pfn(struct zone *zone,
    >> + unsigned long start_pfn,
    >> + unsigned long end_pfn)
    >> {
    >> for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
    >> if (unlikely(!pfn_to_online_page(start_pfn)))
    >> continue;
    >>
    >> - if (unlikely(pfn_to_nid(start_pfn) != nid))
    >> - continue;
    >
    > Are you sure? I thought this is to check against machines with odd layouts, no?

    The zone pointer is unique for every node. (in contrast to the zone index).

    Thanks!

    >
    > /*
    > * Nodes's pfns can be overlapping.
    > * We know some arch can have a nodes layout such as
    > * -------------pfn-------------->
    > * N0 | N1 | N2 | N0 | N1 | N2|....
    > */
    >

    \
     
     \ /
      Last update: 2019-11-27 20:06    [W:7.091 / U:0.216 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site