On Tue, 3 Aug 2010 09:36:45 +0530 Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote: > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2010-08-02 19:20:06]: > > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > > > This patch replaces bit_spinlock with spinlock. In general, > > spinlock has good functinality than bit_spin_lock and we should use > > it if we have a room for it. In 64bit arch, we have extra 4bytes. > > Let's use it. > > expected effects: > > - use better codes. > > - ticket lock on x86-64 > > - para-vitualization aware lock > > etc.. > > > > Chagelog: 20090729 > > - fixed page_cgroup_is_locked(). > > > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > -- > > The additional space usage is a big concern, I think saving space > would be of highest priority. I understand the expected benefits, but > a spinlock_t per page_cgroup is quite expensive at the moment. If > anything I think it should be a config option under CONFIG_DEBUG or > something else to play with and see the side effects. > Hmm. As I already wrote, packing id to flags is not easy. leave 4 bytes space _pad for a while and drop this patch ? I don't like to add CONFIG_DEBUG in this core. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>