Messages in this thread | | | Date | Mon, 23 Mar 2009 10:35:03 -0300 | From | "Luiz Fernando N. Capitulino" <> | Subject | Re: PATCH: Introduce struct vma_link_info |
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Em Fri, 20 Mar 2009 21:36:29 +0100 Peter Zijlstra <peterz@infradead.org> escreveu:
| On Fri, 2009-03-20 at 10:34 -0300, Luiz Fernando N. Capitulino wrote: | > Andrew, | > | > Currently find_vma_prepare() and low-level VMA functions (eg. __vma_link()) | > require callers to provide three parameters to return/pass "link" information | > (pprev, rb_link and rb_parent): | > | > static struct vm_area_struct * | > find_vma_prepare(struct mm_struct *mm, unsigned long addr, | > struct vm_area_struct **pprev, struct rb_node ***rb_link, | > struct rb_node ** rb_parent); | > | > With this patch callers can pass a struct vma_link_info instead: | > | > static struct vm_area_struct * | > find_vma_prepare(struct mm_struct *mm, unsigned long addr, | > struct vma_link_info *link_info); | > | > The code gets simpler and it should be better because less variables | > are pushed into the stack/registers. As shown by the following | > kernel build test: | > | > kernel real user sys | > | > 2.6.29-rc8-vanilla 1136.64 1033.38 82.88 | > 2.6.29-rc8-linfo 1135.07 1032.44 82.92 | > | > I have also ran hackbench, but I can't understand why its result | > indicates a regression: | > | > kernel Avarage of three runs (25 processes groups) | > | > 2.6.29.rc8-vanilla 2.03 | > 2.6.29.rc8-linfo 2.12 | > | > Rik has said to me that this could be inside error margin. So, I'm | > submitting the patch for inclusion. | > | > Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br> | | I'd rather we look into using the threaded RB-tree to get rid of all | this prev crap.
Okay, it makes sense. Also, Eduardo has a point for the hackbench's regression: the patch is probably dropping some of gcc's optimizations on the variables that got packed into the struct (although I haven't checked the assembly yet).
So, better to forget this one.
Are there patches for the threaded tree available already?
-- Luiz Fernando N. Capitulino
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