Unverified Commit ff172d48 authored by Alexandre Ghiti's avatar Alexandre Ghiti Committed by Palmer Dabbelt
Browse files

riscv: Use hugepage mappings for vmemmap 



This will allow better TLB utilization and then should be more performant.

Before:

---[ vmemmap start ]---
0xffff8d8002000000-0xffff8d8012000000    0x000000046ec00000       256M PTE .   ..     ..   D A G . . W R V
---[ vmemmap end ]---

After:

---[ vmemmap start ]---
0xffff8d8002000000-0xffff8d8012000000    0x000000046ec00000       256M PMD .   ..     ..   D A G . . W R V
---[ vmemmap end ]---

Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20231214132935.212864-1-alexghiti@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent d3e591a3

arch/riscv/mm/init.c

+20 −1
Original line number Diff line number Diff line
@@ -1387,10 +1387,29 @@ void __init misc_mem_init(void) 
}



#ifdef CONFIG_SPARSEMEM_VMEMMAP

void __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,

			       unsigned long addr, unsigned long next)

{

	pmd_set_huge(pmd, virt_to_phys(p), PAGE_KERNEL);

}



int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,

				unsigned long addr, unsigned long next)

{

	vmemmap_verify((pte_t *)pmdp, node, addr, next);

	return 1;

}



int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,

			       struct vmem_altmap *altmap)

{

	return vmemmap_populate_basepages(start, end, node, NULL);

	/*

	 * Note that SPARSEMEM_VMEMMAP is only selected for rv64 and that we

	 * can't use hugepage mappings for 2-level page table because in case of

	 * memory hotplug, we are not able to update all the page tables with

	 * the new PMDs.

	 */

	return vmemmap_populate_hugepages(start, end, node, NULL);

}

#endif