On Mon, Mar 01, 2021 at 04:09:45PM +0100, David Hildenbrand wrote: > The information that some PFNs are busy is: > a) not helpful for ordinary users: we don't even know *who* called > alloc_contig_range(). This is certainly not worth a pr_info.*(). > b) not really helpful for debugging: we don't have any details *why* > these PFNs are busy, and that is what we usually care about. > c) not complete: there are other cases where we fail alloc_contig_range() > using different paths that are not getting recorded. > > For example, we reach this path once we succeeded in isolating pageblocks, > but failed to migrate some pages - which can happen easily on > ZONE_NORMAL (i.e., has_unmovable_pages() is racy) but also on ZONE_MOVABLE > i.e., we would have to retry longer to migrate). > > For example via virtio-mem when unplugging memory, we can create quite > some noise (especially with ZONE_NORMAL) that is not of interest to > users - it's expected that some allocations may fail as memory is busy. > > Let's just drop that pr_info_ratelimit() and rather implement a dynamic > debugging mechanism in the future that can give us a better reason why > alloc_contig_range() failed on specific pages. > > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Minchan Kim <minc...@kernel.org> > Cc: Oscar Salvador <osalva...@suse.de> > Cc: Michal Hocko <mho...@kernel.org> > Cc: Vlastimil Babka <vba...@suse.cz> > Signed-off-by: David Hildenbrand <da...@redhat.com>
Reviewed-by: Oscar Salvador <osalva...@suse.de> -- Oscar Salvador SUSE L3
