On Fri, 23 Sep 2005, Andrew Morton wrote:
> big deal. Given that alloc_percpu() is already numa-aware, is that extra
> cross-node fetch and pointer hop really worth all that new code? The new
> version will have to do a tlb load (including a cross-node fetch)
> approximately as often as the old version will get a CPU cache miss on the
> percpu array, maybe?
The current alloc_percpu() is problematic because it has to allocate
entries for all cpus even those who are not online yet. There is no way to
track alloc_percpu entries and therefore no possibility of adding an entry
for a processor if one comes online or for removing one when a processor
goes away.
An additional complication is the allocation of per cpu entries for
processors whose memory node are not online. The current
implementation will fall back on a unspecific allocation but this means
that the placement of the per cpu entries will not be on the node of the
processor!
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |