On Fri, 24 Apr 2009 06:58:39 +0200 Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote: > Stephen Hemminger a écrit : > > In days of old in 2.6.29, netfilter did locketh using a > > lock of the reader kind when doing its table business, and do > > a writer when with pen in hand like a overworked accountant > > did replace the tables. This sucketh and caused the single > > lock to fly back and forth like a poor errant boy. > > > > But then netfilter was blessed with RCU and the performance > > was divine, but alas there were those that suffered for > > trying to replace their many rules one at a time. > > > > So now RCU must be vanquished from the scene, and better > > chastity belts be placed upon this valuable asset most dear. > > The locks that were but one are now replaced by one per suitor. > > > > The repair was made after much discussion involving > > Eric the wise, and Linus the foul. With flowers springing > > up amid the thorns some peace has finally prevailed and > > all is soothed. This patch and purple prose was penned by > > in honor of "Talk like Shakespeare" day. > > > > Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx> > > > Philip Davis of the university’s School of English said : > > "Shakespeare surprises the brain and catches it off guard in > a manner that produces a sudden burst of activity - a sense > of drama created out of the simplest of things." > > http://www.physorg.com/news85664210.html > > > > > --- > > What hath changed over the last two setting suns: > > * more words, mostly correct... > > > > * no need to locketh for writeh on current cpu tis > > always so > > > > * the locking of all cpu's on replace is always done as > > part of the get_counters cycle, so the sychronize swip > > in replace tables is gone with only a comment remaing > > > > include/linux/netfilter/x_tables.h | 55 ++++++++++++++-- > > net/ipv4/netfilter/arp_tables.c | 125 ++++++++++-------------------------- > > net/ipv4/netfilter/ip_tables.c | 126 ++++++++++--------------------------- > > net/ipv6/netfilter/ip6_tables.c | 123 ++++++++++-------------------------- > > net/netfilter/x_tables.c | 55 ++++++++-------- > > 5 files changed, 188 insertions(+), 296 deletions(-) > > > > > > > > static int __init xt_init(void) > > { > > - int i, rv; > > + unsigned int i; > > + int rv; > > + static struct lock_class_key xt_lock_key[NR_CPUS]; > > Could we avoid this [NR_CPUS] thing ? > > > + > > + for_each_possible_cpu(i) { > > + rwlock_t *lock = &per_cpu(xt_info_locks, i); > > + > > + rwlock_init(lock); > > + lockdep_set_class(lock, xt_lock_key+i); > > + } > > > Did you tried : > > static DECLARE_PER_CPU(struct lock_class_key, xt_locks_key); > The lock keys are really only used by lock dep, and I thought per cpu space was more scarce on some arch. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
