From 0b6f15824cc7e431a9706c78bfb9cb3011477ad3 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Date: Tue, 25 Jul 2023 00:37:53 +0530
Subject: mm/vmemmap optimization: split hugetlb and devdax vmemmap
optimization
Arm disabled hugetlb vmemmap optimization [1] because hugetlb vmemmap
optimization includes an update of both the permissions (writeable to
read-only) and the output address (pfn) of the vmemmap ptes. That is not
supported without unmapping of pte(marking it invalid) by some
architectures.
With DAX vmemmap optimization we don't require such pte updates and
architectures can enable DAX vmemmap optimization while having hugetlb
vmemmap optimization disabled. Hence split DAX optimization support into
a different config.
s390, loongarch and riscv don't have devdax support. So the DAX config is
not enabled for them. With this change, arm64 should be able to select
DAX optimization
[1] commit 060a2c92d1b6 ("arm64: mm: hugetlb: Disable HUGETLB_PAGE_OPTIMIZE_VMEMMAP")
Link: https://lkml.kernel.org/r/20230724190759.483013-8-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'include/linux')
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d4ce73c20dcc..b2520dd555f9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3633,7 +3633,7 @@ void vmemmap_free(unsigned long start, unsigned long end,
#endif
#define VMEMMAP_RESERVE_NR 2
-#ifdef CONFIG_ARCH_WANT_OPTIMIZE_VMEMMAP
+#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
static inline bool __vmemmap_can_optimize(struct vmem_altmap *altmap,
struct dev_pagemap *pgmap)
{
--
cgit v1.2.3-70-g09d2