On Sun, May 26, 2013 at 11:30 AM, Rafael Aquini <aqu...@redhat.com> wrote: > On Sun, May 26, 2013 at 10:55:32AM -0400, KOSAKI Motohiro wrote: >> On Sun, May 26, 2013 at 9:52 AM, Rafael Aquini <aqu...@redhat.com> wrote: >> > On Sun, May 26, 2013 at 07:44:56AM -0400, KOSAKI Motohiro wrote: >> >> > + /* >> >> > + * By flagging sys_swapon, a sysadmin can tell >> >> > us to >> >> > + * either do sinle-time area discards only, or >> >> > to just >> >> > + * perform discards for released swap >> >> > page-clusters. >> >> > + * Now it's time to adjust the p->flags >> >> > accordingly. >> >> > + */ >> >> > + if (swap_flags & SWAP_FLAG_DISCARD_ONCE) >> >> > + p->flags &= ~SWP_PAGE_DISCARD; >> >> > + else if (swap_flags & SWAP_FLAG_DISCARD_PAGES) >> >> > + p->flags &= ~SWP_AREA_DISCARD; >> >> >> >> When using old swapon(8), this code turn off both flags, right >> > >> > As the flag that enables swap discards SWAP_FLAG_DISCARD remains meaning >> the >> > same it meant before, when using old swapon(8) >> > (SWP_PAGE_DISCARD|SWP_AREA_DISCARD) >> >> But old swapon(8) don't use neigher SWAP_FLAG_DISCARD_ONCE nor >> SWAP_FLAG_DISCARD_PAGES. It uses only SWAP_FLAG_DISCARD. So, this >> condition disables both SWP_PAGE_DISCARD and SWP_AREA_DISCARD. >> > > This condition _only_ disables one of the new flags orthogonally if swapon(8) > flags a policy to sys_swapon. As old swapon(8) can only flag > SWAP_FLAG_DISCARD, > the original behavior is kept. Nothing will change when one is using an old > swapon(8) with this changeset.
Aha, got it. I misunderstood your code. Thank you. Acked-by: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
