On 2018-06-24 22:57:53 [+0300], Vladimir Davydov wrote: > On Fri, Jun 22, 2018 at 05:12:20PM +0200, Sebastian Andrzej Siewior wrote: > > shadow_lru_isolate() disables interrupts and acquires a lock. It could > > use spin_lock_irq() instead. It also uses local_irq_enable() while it > > could use spin_unlock_irq()/xa_unlock_irq(). > > > > Use proper suffix for lock/unlock in order to enable/disable interrupts > > during release/acquire of a lock. > > > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > > I don't like when a spin lock is locked with local_irq_disabled + > spin_lock and unlocked with spin_unlock_irq - it looks asymmetric. > IMHO the code is pretty easy to follow as it is - local_irq_disable in > scan_shadow_nodes matches local_irq_enable in shadow_lru_isolate. it is not asymmetric because a later patch makes it use spin_lock_irq(), too. If you use local_irq_disable() and a spin_lock() (like you suggest in 3/3 as well) then you separate the locking instruction. It works as expected on vanilla but break other locking implementations like those on RT. Also if the locking changes then the local_irq_disable() part will be forgotten like you saw in 1/3 of this series. Sebastian
