On Mon, Feb 18, 2019 at 12:29:22PM +0100, Peter Zijlstra wrote: > On Fri, Feb 15, 2019 at 05:02:22PM +0000, Steven Price wrote: > > > diff --git a/arch/arm64/include/asm/pgtable.h > > b/arch/arm64/include/asm/pgtable.h > > index de70c1eabf33..09d308921625 100644 > > --- a/arch/arm64/include/asm/pgtable.h > > +++ b/arch/arm64/include/asm/pgtable.h > > @@ -428,6 +428,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, > > unsigned long pfn, > > PMD_TYPE_TABLE) > > #define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \ > > PMD_TYPE_SECT) > > +#define pmd_large(x) pmd_sect(x) > > > > #if defined(CONFIG_ARM64_64K_PAGES) || CONFIG_PGTABLE_LEVELS < 3 > > #define pud_sect(pud) (0) > > @@ -435,6 +436,7 @@ extern pgprot_t phys_mem_access_prot(struct file *file, > > unsigned long pfn, > > #else > > #define pud_sect(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \ > > PUD_TYPE_SECT) > > +#define pud_large(x) pud_sect(x) > > #define pud_table(pud) ((pud_val(pud) & PUD_TYPE_MASK) == \ > > PUD_TYPE_TABLE) > > #endif > > So on x86 p*d_large() also matches p*d_huge() and thp, But it is not > clear to me this p*d_sect() thing does so, given your definitions. > > See here why I care: > > > http://lkml.kernel.org/r/20190201124741.ge31...@hirez.programming.kicks-ass.net
I believe it does not. IIUC our p?d_huge() helpers implicitly handle contiguous entries. That's where you have $N entries in the current level of table that the TLB can cache together as one. Our p?d_sect() helpers only match section entries. That's where we map an entire next-level-table's worth of VA space with a single entry at the current level. Thanks, Mark.
