On Thu 18-03-21 12:10:14, Vlastimil Babka wrote:
> On 3/18/21 11:22 AM, Michal Hocko wrote:
[...]
> > E.g. something like the following
> > diff --git a/mm/internal.h b/mm/internal.h
> > index 1432feec62df..6c5a9066adf0 100644
> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -225,7 +225,13 @@ struct compact_control {
> > unsigned int nr_freepages; /* Number of isolated free pages */
> > unsigned int nr_migratepages; /* Number of pages to migrate */
> > unsigned long free_pfn; /* isolate_freepages search base */
> > - unsigned long migrate_pfn; /* isolate_migratepages search base */
> > + unsigned long migrate_pfn; /* Acts as an in/out parameter to page
> > + * isolation.
> > + * isolate_migratepages uses it as a
> > search base.
> > + * isolate_migratepages_block will
> > update the
> > + * value the next pfn after the last
> > isolated
> > + * one.
> > + */
>
> Fair enough. I would even stop pretending we might cram something useful in
> the
> rest of the line, and move all the comments to blocks before the variables.
> There might be more of them that would deserve more thorough description.
Yeah, makes sense. I am not a fan of the above form of documentation.
Btw. maybe renaming the field would be even better, both from the
intention and review all existing users. I would go with pfn_iter or
something that wouldn't make it sound like migration specific.
--
Michal Hocko
SUSE Labs
