Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | Re: process creation time increases linearly with shmem | Date | Thu, 25 Aug 2005 16:22:08 +0200 |
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> Would it be worth trying to do something like this?
Maybe. Shouldn't be very hard though - you just need to check if the VMA is backed by an object and if yes don't call copy_page_range for it.
I think it just needs (untested)
Index: linux-2.6.13-rc5-misc/kernel/fork.c =================================================================== --- linux-2.6.13-rc5-misc.orig/kernel/fork.c +++ linux-2.6.13-rc5-misc/kernel/fork.c @@ -265,7 +265,8 @@ static inline int dup_mmap(struct mm_str rb_parent = &tmp->vm_rb; mm->map_count++; - retval = copy_page_range(mm, current->mm, tmp); + if (!file && !is_vm_hugetlb_page(vma)) + retval = copy_page_range(mm, current->mm, tmp); spin_unlock(&mm->page_table_lock); if (tmp->vm_ops && tmp->vm_ops->open) But I'm not sure it's a good idea in all cases. Would need a lot of benchmarking at least.
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