On Wed, 28 Dec 2011, Hugh Dickins wrote: > On Thu, 29 Dec 2011, KOSAKI Motohiro wrote: > > > > Hmm... > > scan_mapping_unevictable_pages() is always under spinlock? > > Yikes, how dreadful! Dreadful that it's like that, and dreadful > that I didn't notice. Many thanks for spotting, consider this > patch summarily withdrawn. All the more need for some patch like > this, but no doubt it was "easier" to do it all under the spinlock, > so the right replacement patch may not be so obvious. It's not so bad, I think: that info->lock isn't really needed across scan_mapping_unevictable_pages(), which has to deal with races on a page by page basis anyway. But it's not the only spinlock, there is also ipc_lock() (often) held in the level above: so I'll have to restructure it a little. And now that it's no longer a one-liner, I really ought to add a patch fixing another bug I introduced here - if there were swapped pages when the area was SHM_LOCKed, find_get_pages() will give up if it hits a row of PAGEVEC_SIZE swap entries, leaving subsequent pages unevictable. But I'd better empty my queue of trivia before going on to that. Hugh -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>