On Thu, Dec 19, 2013 at 09:23:51AM +0200, Julian Anastasov wrote:
>
> Hello,
>
> On Wed, 13 Nov 2013, Julian Anastasov wrote:
>
> > On Tue, 12 Nov 2013, Geert Uytterhoeven wrote:
> >
> > > net/netfilter/ipvs/ip_vs_sync.c: In function 'sync_thread_master':
> > > net/netfilter/ipvs/ip_vs_sync.c:1640:8: warning: unused variable 'ret'
> > > [-Wunused-variable]
> > >
> > > Commit 35a2af94c7ce7130ca292c68b1d27fcfdb648f6b ("sched/wait: Make the
> > > __wait_event*() interface more friendly") changed how the interruption
> > > state is returned. However, sync_thread_master() ignores this state,
> > > now causing a compile warning.
> > >
> > > According to Julian Anastasov <j...@ssi.bg>, this behavior is OK:
> > >
> > > "Yes, your patch looks ok to me. In the past we used ssleep() but IPVS
> > > users were confused why IPVS threads increase the load average. So,
> > > we
> > > switched to _interruptible calls and later the socket polling was
> > > added."
> > >
> > > Document this, as requested by Peter Zijlstra, to avoid precious
> > > developers
> > > disappearing in this pitfall in the future.
> > >
> > > Signed-off-by: Geert Uytterhoeven <ge...@linux-m68k.org>
> > > ---
> > > v2: Document that sync_thread_master() ignores the interruption state,
> > >
> > > net/netfilter/ipvs/ip_vs_sync.c | 5 ++++-
> > > 1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/net/netfilter/ipvs/ip_vs_sync.c
> > > b/net/netfilter/ipvs/ip_vs_sync.c
> > > index f63c2388f38d..db801263ee9f 100644
> > > --- a/net/netfilter/ipvs/ip_vs_sync.c
> > > +++ b/net/netfilter/ipvs/ip_vs_sync.c
> > > @@ -1637,7 +1637,10 @@ static int sync_thread_master(void *data)
> > > continue;
> > > }
> > > while (ip_vs_send_sync_msg(tinfo->sock, sb->mesg) < 0) {
> > > - int ret = __wait_event_interruptible(*sk_sleep(sk),
> > > + /* (Ab)use interruptible sleep to avoid increasing
> > > + * the load avg.
> > > + */
> > > + __wait_event_interruptible(*sk_sleep(sk),
> > > sock_writeable(sk) ||
> > > kthread_should_stop());
> > > if (unlikely(kthread_should_stop()))
> >
> > Fabio Estevam posted similar change too early but
> > we are better with such comment.
> >
> > Acked-by: Julian Anastasov <j...@ssi.bg>
> >
> > Also, the TASK_UNINTERRUPTIBLE | TASK_IDLE idea looks good
> > to me. If such change is planned may be the above patch
> > better not to go via the ipvs-next tree to avoid conflicts?
> > As we don't have any changes in this area let us know if
> > someone takes the above patch for another tree.
>
> Simon, lets apply this patch to ipvs-next tree...
Thanks, done.
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