On Thu, Mar 19, 2015 at 11:29:52AM -0700, Dave Hansen wrote: > On 03/19/2015 10:08 AM, Kirill A. Shutemov wrote: > > The odd exception is PG_dirty: sound uses compound pages and maps them > > with PTEs. NO_COMPOUND triggers VM_BUG_ON() in set_page_dirty() on > > handling shared fault. Let's use HEAD for PG_dirty. > > Can we get the sound guys to look at this, btw? It seems like an odd > thing that we probably don't want to keep around, right? CC: +sound guys I'm not sure what is right fix here. At the time adding __GFP_COMP was a fix: see f3d48f0373c1. Other odd part about __GFP_COMP here is that we have ->_mapcount in tail pages to be used for both: mapcount of the individual page and for gup pins. __compound_tail_refcounted() doesn't recognize that we don't need tail page accounting for these pages. Hugh, I tried to ask you about the situation several times (last time on the summit). Any comments? -- Kirill A. Shutemov -- 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>