Re: [PATCH 01/13] arm64: mm: Add p?d_large() definitions
From: Mark Rutland <mark.rutland@arm.com>
Date: 2019-02-18 14:47:53
Also in:
linux-mm, lkml
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:quoted
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) #endifSo 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.GE31552@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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel