try_to_swap_out() clears pte before checking for delalloc page

[Marcelo Tosatti <marcelo@xxxxxxxxxxxxxxxx>]

Minor issue, anyway...

In the XFS tree, file mm/vmscan.c, function try_to_swap_out();


        /* From this point on, the odds are that we're going to
         * nuke this pte, so read and clear the pte.  This hook
         * is needed on CPUs which update the accessed and dirty
         * bits in hardware.
         */
        pte = ptep_get_and_clear(page_table);
        flush_tlb_page(vma, address);

        if (DelallocPage(page)) {
                goto out_unlock_restore;
        }



During pte aging & unmapping activity, each scanned pte pointing to a
delalloc page will be cleared (ptep_get_and_clear), its TLB entry will be
invalidated and the pte will be mapped again.

The DelallocPage check can be moved before the pte&tlb clearing to avoid
the unecessary work.

Russell, you're supposed to merge new kernels, right?

Could you please change that while merging ? (the code changed anyway so
you'll have to touch it)

Thanks