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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Jul 15, 2026 at 12:34:29PM +0200, Geert Uytterhoeven wrote: > Hi Yeoreum, > > On Wed, 15 Jul 2026 at 11:42, Yeoreum Yun wrote: > > > On Tue, 14 Jul 2026 at 18:51, Yeoreum Yun wrote: > > > > --- a/mm/ptdump.c > > > > +++ b/mm/ptdump.c > > > > @@ -190,6 +190,23 @@ void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) > > > > st->note_page_flush(st); > > > > } > > > > > > > > +bool pdtump_pt_level_first(struct mm_struct *mm, int level) > > > > +{ > > > > + if (!mm || level > CONFIG_PGTABLE_LEVELS) > > > > + return false; > > > > + > > > > + if (mm_pmd_folded(mm) && level == 3) > > > > + return true; > > > > + if (mm_pud_folded(mm) && level == 2) > > > > + return true; > > > > + if (mm_p4d_folded(mm) && level == 1) > > > > + return true; > > > > > > Is this order (... && level == ...) the optimal order? > > > On arm64, mm_pud_folded() and mm_p4d_folded() perform several checks. > > > > > > > + if (level == 0) > > > > + return true; > > > > + > > > > + return false; > > > > +} > > > > It is. since the purpose of ptdump_pt_level_first is designed to be used > > in the *callback* of pXd_entry(). IOW, if we check level 0 first, > > it always returns wrong return in folded case. > > I meant the order inside the if () conditions. > E.g. > "if (mm_pud_folded(mm) && level == 2)" does the expensive check first. > "if (level == 2 && mm_pud_folded(mm))" does the cheap check first. Ah. Yeap that would be better. Thanks! -- Sincerely, Yeoreum Yun _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv