For prefetches of NULL (as when walking a short linked list), PPC64 will in
some cases take a performance hit. The hardware needs to do the TLB walk,
and said walk will always miss, which means (up to) two L2 misses as
penalty. This seems to hurt overall performance, so for NULL pointers skip
the prefetch alltogether.
Signed-off-by: Olof Johansson <olof@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Olof Johansson