| Message ID | 1469582616-5729-4-git-send-email-liang.z.li@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jul 27, 2016 at 09:23:32AM +0800, Liang Li wrote: > Expose the function to get the max pfn, so it can be used in the > virtio-balloon device driver. > > Signed-off-by: Liang Li <liang.z.li@intel.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Vlastimil Babka <vbabka@suse.cz> > Cc: Mel Gorman <mgorman@techsingularity.net> > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Cornelia Huck <cornelia.huck@de.ibm.com> > Cc: Amit Shah <amit.shah@redhat.com> > --- > mm/page_alloc.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 8b3e134..7da61ad 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -4517,6 +4517,12 @@ void show_free_areas(unsigned int filter) > show_swap_cache_info(); > } > > +unsigned long get_max_pfn(void) > +{ > + return max_pfn; > +} > +EXPORT_SYMBOL(get_max_pfn); > + This needs a coment that this can change at any time. So it's only good as a hint e.g. for sizing data structures. > static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) > { > zoneref->zone = zone; > -- > 1.9.1
On 07/27/2016 03:08 PM, Michael S. Tsirkin wrote: >> > +unsigned long get_max_pfn(void) >> > +{ >> > + return max_pfn; >> > +} >> > +EXPORT_SYMBOL(get_max_pfn); >> > + > > This needs a coment that this can change at any time. > So it's only good as a hint e.g. for sizing data structures. Or, if we limit the batches to 1GB like you suggested earlier, then we might not even need this exported. It would mean that in the worst case, we temporarily waste 28k out of the 32k allocation for a small VM that had <128MB of memory. That seems like a small price to pay for not having to track max_pfn anywhere.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8b3e134..7da61ad 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4517,6 +4517,12 @@ void show_free_areas(unsigned int filter) show_swap_cache_info(); } +unsigned long get_max_pfn(void) +{ + return max_pfn; +} +EXPORT_SYMBOL(get_max_pfn); + static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref) { zoneref->zone = zone;
Expose the function to get the max pfn, so it can be used in the virtio-balloon device driver. Signed-off-by: Liang Li <liang.z.li@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Cornelia Huck <cornelia.huck@de.ibm.com> Cc: Amit Shah <amit.shah@redhat.com> --- mm/page_alloc.c | 6 ++++++ 1 file changed, 6 insertions(+)