On Thu, 11 Mar 2010 13:31:23 +0900 Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote: > On Wed, 10 Mar 2010 09:26:24 +0530, Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote: > > * nishimura@xxxxxxxxxxxxxxxxx <nishimura@xxxxxxxxxxxxxxxxx> [2010-03-10 10:43:09]: > I made a patch(attached) using both local_irq_disable/enable and local_irq_save/restore. > local_irq_save/restore is used only in mem_cgroup_update_file_mapped. > > And I attached a histogram graph of 30 times kernel build in root cgroup for each. > > before_root: no irq operation(original) > after_root: local_irq_disable/enable for all > after2_root: local_irq_save/restore for all > after3_root: mixed version(attached) > > hmm, there seems to be a tendency that before < after < after3 < after2 ? > Should I replace save/restore version to mixed version ? > IMHO, starting from after2_root version is the easist. If there is a chance to call lock/unlock page_cgroup can be called in interrupt context, we _have to_ disable IRQ, anyway. And if we have to do this, I prefer migration_lock rather than this mixture. BTW, how big your system is ? Balbir-san's concern is for bigger machines. But I'm not sure this change is affecte by the size of machines. I'm sorry I have no big machine, now. I'll consider yet another fix for race in account migration if I can. 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>