On Sat, 2013-06-22 at 08:10 +0800, Alex Shi wrote: > On 06/22/2013 07:51 AM, Tim Chen wrote: > > Doing cmpxchg will cause cache bouncing when checking > > sem->count. This could cause scalability issue > > in a large machine (e.g. a 80 cores box). > > > > A pre-read of sem->count can mitigate this. > > > > Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx> > > Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> > > Hi Tim, > there is a technical error in this patch. > the "From: " line should be 'Alex Shi', since he made the most input of > this patch. > > And I still think split this patch to 4 smaller will make it more simple > to review, that I had sent you and Davidlohr. Yep, and you had updated the changelog for 1/4: rwsem: check the lock before cpmxchg in down_write_trylock to: "cmpxchg will cause cache bouncing when do the value checking, that cause scalability issue in a large machine (like a 80 cores box). A lock status pre-read can relief this." > > could you like to re-send with my 4 patch version? :) For those 4 patches: Acked-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>