Messages in this thread Patch in this message | | | Subject | [patch 11/18] remap_file_pages protection support: also set VM_NONLINEAR on nonuniform VMAs | From | blaisorblade@yahoo ... | Date | Fri, 26 Aug 2005 18:53:42 +0200 |
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From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
To simplify the VM code, and to reflect expected application usage, we decide to also set VM_NONLINEAR when setting VM_NONUNIFORM. Otherwise, we'd have to possibly save nonlinear PTEs even on paths which cope with linear VMAs. It's possible, but intrusive (it's done in one of the next patches).
Obviously, this has a performance cost, since we potentially have to handle a linear VMA with nonlinear handling code. But I don't know of any application which might have this usage.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> ---
linux-2.6.git-paolo/mm/fremap.c | 27 ++++++++++++++------------- 1 files changed, 14 insertions(+), 13 deletions(-)
diff -puN mm/fremap.c~rfp-nonuniform-implies-nonlinear mm/fremap.c --- linux-2.6.git/mm/fremap.c~rfp-nonuniform-implies-nonlinear 2005-08-25 12:50:00.000000000 +0200 +++ linux-2.6.git-paolo/mm/fremap.c 2005-08-25 12:50:00.000000000 +0200 @@ -246,8 +246,9 @@ retry: if (!vma->vm_private_data || (vma->vm_flags & (VM_NONLINEAR|VM_RESERVED))) { /* Must set VM_NONLINEAR before any pages are populated. */ - if (pgoff != linear_page_index(vma, start) && - !(vma->vm_flags & VM_NONLINEAR)) { + if (!(vma->vm_flags & VM_NONLINEAR) && + (pgoff != linear_page_index(vma, start) || + pgprot_val(pgprot) != pgprot_val(vma->vm_page_prot))) { if (!(vma->vm_flags & VM_SHARED)) goto out_unlock; if (!has_write_lock) { @@ -264,19 +265,19 @@ retry: vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); flush_dcache_mmap_unlock(mapping); spin_unlock(&mapping->i_mmap_lock); - } - if (pgprot_val(pgprot) != pgprot_val(vma->vm_page_prot) && - !(vma->vm_flags & VM_NONUNIFORM)) { - if (!(vma->vm_flags & VM_SHARED)) - goto out_unlock; - if (!has_write_lock) { - up_read(&mm->mmap_sem); - down_write(&mm->mmap_sem); - has_write_lock = 1; - goto retry; + if (!(vma->vm_flags & VM_NONUNIFORM) && + pgprot_val(pgprot) != pgprot_val(vma->vm_page_prot)) { + if (!(vma->vm_flags & VM_SHARED)) + goto out_unlock; + if (!has_write_lock) { + up_read(&mm->mmap_sem); + down_write(&mm->mmap_sem); + has_write_lock = 1; + goto retry; + } + vma->vm_flags |= VM_NONUNIFORM; } - vma->vm_flags |= VM_NONUNIFORM; } /* Do NOT hold the write lock while doing any I/O, nor when _ - 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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