On Thu, 3 Nov 2011 00:11:23 +0100 "Rafael J. Wysocki" <[email protected]> wrote:
> On Wednesday, November 02, 2011, Oleg Nesterov wrote: > > Hi, > > > > On 11/01, Tejun Heo wrote: > > > > > > For now, let's go with the count/dont_count. Can you please write up > > > a patch for that? Jeff, does this seem okay to you? > > > > OK, will do in a minute. On top of > > "[PATCH pm] freezer: fix wait_event_freezable/__thaw_task races" > > you sent. (btw, thanks, I forgout about it ;) > > > > Rafael, could you remind why freezer_do_not_count/freezer_count check > > ->mm != NULL ? > > You're asking difficult questions. ;-) > > The intention was to prevent PF_FREEZER_SKIP from having any effect on > kernel threads, IIRC. Anyway, there are only two legitimate users of it > (vfork and apm_ioctl) and in both cases the task in question is user space. > > > The comment says "However, we don't want kernel threads to be frozen", > > but it is not clear anyway. A kernel thread simply shouldn't use this > > interface if it doesn't want to freeze. > > > > And in any case, PF_KTHREAD looks better if we really need to filter > > out the kernel threads. > > PF_FREEZER_SKIP was introduced specifically with vfork in mind and I'm not > sure if it's a good idea to re-use it for something else (at least not for > something entirely obvious). > FWIW, wrapping wait_event_killable in freezer_do_not_count/freezer_count seems to work. The machine suspends consistently with it. It sounds like Rafael has concerns about this scheme however, so I'll let you guys argue this out :) Once you tell me the right scheme to use, I'll be happy to fix up cifs and nfs to use it. Thanks, -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
