On Thu, Dec 06, 2012 at 10:19:35AM -0800, Linus Torvalds wrote: > On Thu, Dec 6, 2012 at 9:55 AM, Mel Gorman <mgorman@xxxxxxx> wrote: > > > > Yeah. I was listening to a talk while I was writing it, a bit cranky and > > didn't see why I should suffer alone. > > Makes sense. > > > Quasimoto strikes again > > Is that Quasimodo's Japanese cousin? > > > - end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn); > > + > > + /* > > + * As pfn may not start aligned, pfn+pageblock_nr_page > > + * may cross a MAX_ORDER_NR_PAGES boundary and miss > > + * a pfn_valid check. Ensure isolate_freepages_block() > > + * only scans within a pageblock. > > + */ > > + end_pfn = ALIGN(pfn + pageblock_nr_pages, pageblock_nr_pages); > > + end_pfn = min(end_pfn, end_pfn); > > Ok, this looks much nicer, except it's obviously buggy. The > min(end_pfn, end_pfn) thing is insane, and I'm sure you meant for that > line to be > > + end_pfn = min(end_pfn, zone_end_pfn); > > Henrik, does that - corrected - patch (*instead* of the previous one, > not in addition to) also fix your issue? Yes - I can no longer trigger the failpath, so it seems to work. Mel, enjoy the rest of the talk. ;-) Generally, I am a bit surprised that noone hit this before, given that it was quite easy to trigger. I will check 3.6 as well. Thanks, Henrik -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>