Messages in this thread Patch in this message | | | Date | Tue, 17 Aug 2004 10:18:29 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] voluntary-preempt-2.6.8.1-P1 |
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* Ingo Molnar <mingo@elte.hu> wrote:
> > Yes, Ingo identified an issue with copy_page_range, I don't think it's > > fixed yet. See the voluntary-preempt-2.6.8.1-P0 thread. > > right, it's not fixed yet. It's not a trivial critical section - we > are holding two locks and are mapping two atomic kmaps.
fortunately it's easier than i thought - neither the source pmd nor the target pmd can go away so we can simply drop the locks, reschedule, and remap. Does the patch below (ontop of -P3) fix the copy_page_range() latencies you are seeing?
Ingo
--- linux/mm/memory.c.orig +++ linux/mm/memory.c @@ -337,6 +337,15 @@ cont_copy_pte_range_noset: } src_pte++; dst_pte++; + if (voluntary_need_resched()) { + pte_unmap_nested(src_pte); + pte_unmap(dst_pte); + spin_unlock(&src->page_table_lock); + cond_resched_lock(&dst->page_table_lock); + spin_lock(&src->page_table_lock); + dst_pte = pte_offset_map(dst_pmd, address); + src_pte = pte_offset_map_nested(src_pmd, address); + } } while ((unsigned long)src_pte & PTE_TABLE_MASK); pte_unmap_nested(src_pte-1); pte_unmap(dst_pte-1); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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