Messages in this thread |  | | Date | Sun, 3 Jul 2022 21:48:13 +0800 | Subject | Re: [RFC PATCH v3 1/3] mm: Factor out the pagetable pages account into new helper function | From | Baolin Wang <> |
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On 7/2/2022 6:15 PM, Mike Rapoport wrote: > On Fri, Jul 01, 2022 at 04:00:59PM +0800, Baolin Wang wrote: >> >> >> On 6/30/2022 10:11 PM, Mike Rapoport wrote: >>> On Thu, Jun 30, 2022 at 07:11:14PM +0800, Baolin Wang wrote: >>>> Factor out the pagetable pages account into new helper functions to avoid >>>> duplicated code. Meanwhile these helper functions also will be used to >>>> account pagetable pages which do not need split pagetale lock. >>>> >>>> Meanwhile convert to use mod_lruvec_page_state() in case of non-order-0 >>>> page table allocation. >>> >>> These are *very* rare. I think only parisc may have non-order-0 pmd and pud >>> tables. >> >> s390 also has non-order-0 page table allocation, but they both do not use >> the generic page table allocation now. >> >>> With that, I'd suggest making use of compound_nr() build time opt-in. >> >> After more thinking, I'd prefer to change back to use >> inc_lruvec_page_state()/dec_lruvec_page_state(), since now no architecures >> will need non-order-0 page table allocation. >> >> After this patchset, I plan to convert parisc and s390 to use generic >> pagetable allocation, then I will add non-order-0 page table allocation >> support. Like Matthew suggested, maybe I need change the API to pass the >> number of pages. > > I think it would be simpler to add proper accounting to s390 and parisc > versions than make them use the generic allocation functions. Moreover, API > change to support these cases feels like unnecessary churn to me.
Got it. Thanks.
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