On Wed, 12 Sep 2007 02:05:25 -0700 (PDT) David Miller <[EMAIL PROTECTED]> wrote:
> From: Eric Dumazet <[EMAIL PROTECTED]> > Date: Tue, 11 Sep 2007 14:56:13 +0200 > > > When the periodic IP route cache flush is done (every 600 seconds on > > default configuration), some hosts suffer a lot and eventually trigger > > the "soft lockup" message. > > > > dst_run_gc() is doing a scan of a possibly huge list of dst_entries, > > eventually freeing some (less than 1%) of them, while holding the > > dst_lock spinlock for the whole scan. > > > > Then it rearms a timer to redo the full thing 1/10 s later... > > The slowdown can last one minute or so, depending on how active are > > the tcp sessions. > > > > This second version of the patch converts the processing from a softirq > > based one to a workqueue. > > > > Even if the list of entries in garbage_list is huge, host is still > > responsive to softirqs and can make progress. > > > > Instead of reseting gc timer to 0.1 second if one entry was freed in a > > gc run, we do this if more than 10% of entries were freed. > > I like this patch a lot, some minor fix is needed though: Thank you I also spoted a missing static before DECLARE_DELAYED_WORK(dst_gc_work, dst_gc_task); no need to stress Adrian on this :) > > > + __builtin_prefetch(&next->next, 1, 0); > > Please use prefetch() instead of a direct explicit > call to a gcc-specific routine :-) Unfortunatly, there is no equivalent for this one. This gives on my Opterons a nice "prefetchnta" prefetch(addr) is more like __builtin_prefetch(addr, 0, 3) I would like to avoid to zap L2 cache with useless data. __builtin_prefetch() is included from gcc 3.1 (2002), so every platform should support it, as linux-2.6 requires gcc 3.2 at least. I guess you are going to tell me to first publish a patch to lkml :) Thank you Eric - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
