From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamal Subject: Re: [PATCH 20/31]: pkt_sched: Perform bulk of qdisc destruction in RCU. Date: Sun, 20 Jul 2008 22:33:57 -0400 Message-ID: <1216607637.4847.172.camel@localhost> References: <1216568119.4847.101.camel@localhost> <20080721001119.GA6515@gondor.apana.org.au> Reply-To: hadi-fAAogVwAN2Kw5LPnMra/2Q@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: kaber-dcUjhNyLwpNeoWH0uzbU5w@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org, linux-wireless-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Herbert Xu Return-path: In-Reply-To: <20080721001119.GA6515-lOAM2aK0SrRLBo1qDEOMRrpzq4S04n8Q@public.gmane.org> Sender: linux-wireless-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On Mon, 2008-21-07 at 08:11 +0800, Herbert Xu wrote: > This is exactly what I want to get rid of because otherwise even > if no index was specified we'll still do a hash insertion which > simply falls apart with a small hash table. Using a large hash > table on the other is bad for people who only have a few rules. True. But note: this is only during rule creation - once you create the rule (user space to kernel path), then no more hash table reference. Fast path has already a filter with actions attached, and is a mere pointer dereference. > We could do a dynamic table but so far I'm not convinced that > it's worth anybody's effort to implement :) If user<->kernel performance insertion/deletion is important, it is worth it. For example: Dave implemented dynamic hash tables on xfrm (voip setup time with ipsec is a metric used in the industry in that case) . The only operational problem i had with xfrm was lack of an upper bound of how large a table can grow; i would rather user space be told ENOMEM than continuing to grow in some cases (I actually implemented a patch which put a stop after a certain number of sad/spd - but i dont expect hugs if i was to post it;->). cheers, jamal -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html