Messages in this thread | | | Subject | Re: [patch 2/4] lglock: introduce special lglock and brlock spin locks | From | Eric Dumazet <> | Date | Fri, 04 Jun 2010 09:56:03 +0200 |
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Le vendredi 04 juin 2010 à 16:43 +1000, Nick Piggin a écrit : > pièce jointe document texte brut (kernel-introduce-brlock.patch) > This patch introduces "local-global" locks (lglocks). These can be used to: > > - Provide fast exclusive access to per-CPU data, with exclusive access to > another CPU's data allowed but possibly subject to contention, and to provide > very slow exclusive access to all per-CPU data. > - Or to provide very fast and scalable read serialisation, and to provide > very slow exclusive serialisation of data (not necessarily per-CPU data). > > Brlocks are also implemented as a short-hand notation for the latter use > case. > > Thanks to Paul for local/global naming convention. > > Cc: linux-kernel@vger.kernel.org > Cc: linux-fsdevel@vger.kernel.org > Cc: Al Viro <viro@ZenIV.linux.org.uk> > Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > Cc: Frank Mayhar <fmayhar@google.com>, > Cc: John Stultz <johnstul@us.ibm.com> > Cc: Andi Kleen <ak@linux.intel.com> > Signed-off-by: Nick Piggin <npiggin@suse.de> > --- > include/linux/lglock.h | 165 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 165 insertions(+) >
IMHO some changes in Documentation/ would be needed
> \ > + void name##_global_lock(void) { \ > + int i; \ > + preempt_disable(); \ > + rwlock_acquire(&name##_lock_dep_map, 0, 0, _RET_IP_); \ > + for_each_online_cpu(i) { \
for_each_possible_cpu()
> + arch_spinlock_t *lock; \ > + lock = &per_cpu(name##_lock, i); \ > + arch_spin_lock(lock); \ > + } \ > + } \ > + EXPORT_SYMBOL(name##_global_lock); \ > + \ > + void name##_global_unlock(void) { \ > + int i; \ > + rwlock_release(&name##_lock_dep_map, 1, _RET_IP_); \ > + for_each_online_cpu(i) { \
for_each_possible_cpu()
> + arch_spinlock_t *lock; \ > + lock = &per_cpu(name##_lock, i); \ > + arch_spin_unlock(lock); \ > + } \ > + preempt_enable(); \ > + } \ > + EXPORT_SYMBOL(name##_global_unlock); \ > + \
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