Messages in this thread | | | Date | Mon, 7 May 2007 10:11:29 -0700 | From | "Siddha, Suresh B" <> | Subject | Re: [PATCH 0/2] Add percpu smp cacheline align section |
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On Sat, May 05, 2007 at 09:52:27AM -0700, Christoph Lameter wrote: > On Fri, 4 May 2007, Fenghua Yu wrote: > > > This is follow-up for Suresh's runqueue align in smp patch at: > > [1]http://www.uwsg.iu.edu/hypermail/linux/kernel/0704.1/0340.html > > > > The patches place all of smp cacheline aligned percpu data into > > .data.percpu.cacheline_aligned_in_smp. Other percpu data is still in > > data.percpu section. The patches can reduce cache line access in SMP and > > reduce alignment gap waste. The patches also define PERCPU macro for > > vmlinux.lds.S for code clean up. > > Ummm... The per cpu area is for exclusive use of a particular processor. > If there is contention in the per cpu area then a data object needs to be > removed from the per cpu area because the object is *not* accessed only > from a certain cpu.
Christoph, This data(that is being accessed by other cpus) also needs to be defined for each cpu and as such it is getting appended (and clearly seperated in a different section) to the data which is accessed only by the local cpu.
Not sure what your concern is.
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