* [PATCH V3 0/3] mm/hugetlb: Add some new generic fallbacks
@ 2020-05-08 3:07 Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET Anshuman Khandual
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-08 3:07 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Anshuman Khandual, Thomas Bogendoerfer,
Borislav Petkov, Paul Walmsley, Thomas Gleixner, linux-arm-kernel,
Tony Luck, linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller, Mike Kravetz
This series adds the following new generic fallbacks. Before that it drops
__HAVE_ARCH_HUGE_PTEP_GET from arm64 platform.
1. is_hugepage_only_range()
2. arch_clear_hugepage_flags()
This has been boot tested on arm64 and x86 platforms but built tested on
some more platforms including the changed ones here. This series applies
on v5.7-rc4. After this arm (32 bit) remains the sole platform defining
it's own huge_ptep_get() via __HAVE_ARCH_HUGE_PTEP_GET.
Changes in V3:
- Added READ_ONCE() in generic huge_ptep_get() per Will
Changes in V2: (https://patchwork.kernel.org/project/linux-mm/list/?series=282947)
- Adopted "#ifndef func" method (adding a single symbol to namespace) per Andrew
- Updated the commit messages in [PATCH 2/3] and [PATCH 3/3] as required
Changes in V1: (https://patchwork.kernel.org/project/linux-mm/list/?series=270677)
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Anshuman Khandual (3):
arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET
mm/hugetlb: Define a generic fallback for is_hugepage_only_range()
mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags()
arch/arm/include/asm/hugetlb.h | 7 +------
arch/arm64/include/asm/hugetlb.h | 13 +------------
arch/ia64/include/asm/hugetlb.h | 5 +----
arch/mips/include/asm/hugetlb.h | 11 -----------
arch/parisc/include/asm/hugetlb.h | 10 ----------
arch/powerpc/include/asm/hugetlb.h | 5 +----
arch/riscv/include/asm/hugetlb.h | 10 ----------
arch/s390/include/asm/hugetlb.h | 8 +-------
arch/sh/include/asm/hugetlb.h | 7 +------
arch/sparc/include/asm/hugetlb.h | 10 ----------
arch/x86/include/asm/hugetlb.h | 10 ----------
include/asm-generic/hugetlb.h | 2 +-
include/linux/hugetlb.h | 14 ++++++++++++++
13 files changed, 21 insertions(+), 91 deletions(-)
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET
2020-05-08 3:07 [PATCH V3 0/3] mm/hugetlb: Add some new generic fallbacks Anshuman Khandual
@ 2020-05-08 3:07 ` Anshuman Khandual
2020-05-08 22:09 ` Mike Kravetz
2020-05-08 3:07 ` [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range() Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags() Anshuman Khandual
2 siblings, 1 reply; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-08 3:07 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Catalin Marinas, Will Deacon, linux-kernel, linux-arm-kernel,
Anshuman Khandual
Platform specific huge_ptep_get() is required only when fetching the huge
PTE involves more than just dereferencing the page table pointer. This is
not the case on arm64 platform. Hence huge_ptep_pte() can be dropped along
with it's __HAVE_ARCH_HUGE_PTEP_GET subscription. Before that, it updates
the generic huge_ptep_get() with READ_ONCE() which will prevent known page
table issues with THP on arm64.
https://lore.kernel.org/r/1506527369-19535-1-git-send-email-will.deacon@arm.com/
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm64/include/asm/hugetlb.h | 6 ------
include/asm-generic/hugetlb.h | 2 +-
2 files changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index 2eb6c234d594..b88878ddc88b 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -17,12 +17,6 @@
extern bool arch_hugetlb_migration_supported(struct hstate *h);
#endif
-#define __HAVE_ARCH_HUGE_PTEP_GET
-static inline pte_t huge_ptep_get(pte_t *ptep)
-{
- return READ_ONCE(*ptep);
-}
-
static inline int is_hugepage_only_range(struct mm_struct *mm,
unsigned long addr, unsigned long len)
{
diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
index 822f433ac95c..40f85decc2ee 100644
--- a/include/asm-generic/hugetlb.h
+++ b/include/asm-generic/hugetlb.h
@@ -122,7 +122,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
#ifndef __HAVE_ARCH_HUGE_PTEP_GET
static inline pte_t huge_ptep_get(pte_t *ptep)
{
- return *ptep;
+ return READ_ONCE(*ptep);
}
#endif
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range()
2020-05-08 3:07 [PATCH V3 0/3] mm/hugetlb: Add some new generic fallbacks Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET Anshuman Khandual
@ 2020-05-08 3:07 ` Anshuman Khandual
2020-05-08 22:22 ` Mike Kravetz
2020-05-08 3:07 ` [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags() Anshuman Khandual
2 siblings, 1 reply; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-08 3:07 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Anshuman Khandual, Thomas Bogendoerfer,
Borislav Petkov, Paul Walmsley, Thomas Gleixner, linux-arm-kernel,
Tony Luck, linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller, Mike Kravetz
There are multiple similar definitions for is_hugepage_only_range() on
various platforms. Lets just add it's generic fallback definition for
platforms that do not override. This help reduce code duplication.
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm/include/asm/hugetlb.h | 6 ------
arch/arm64/include/asm/hugetlb.h | 6 ------
arch/ia64/include/asm/hugetlb.h | 1 +
arch/mips/include/asm/hugetlb.h | 7 -------
arch/parisc/include/asm/hugetlb.h | 6 ------
arch/powerpc/include/asm/hugetlb.h | 1 +
arch/riscv/include/asm/hugetlb.h | 6 ------
arch/s390/include/asm/hugetlb.h | 7 -------
arch/sh/include/asm/hugetlb.h | 6 ------
arch/sparc/include/asm/hugetlb.h | 6 ------
arch/x86/include/asm/hugetlb.h | 6 ------
include/linux/hugetlb.h | 9 +++++++++
12 files changed, 11 insertions(+), 56 deletions(-)
diff --git a/arch/arm/include/asm/hugetlb.h b/arch/arm/include/asm/hugetlb.h
index 318dcf5921ab..9ecd516d1ff7 100644
--- a/arch/arm/include/asm/hugetlb.h
+++ b/arch/arm/include/asm/hugetlb.h
@@ -14,12 +14,6 @@
#include <asm/hugetlb-3level.h>
#include <asm-generic/hugetlb.h>
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr, unsigned long len)
-{
- return 0;
-}
-
static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_dcache_clean, &page->flags);
diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index b88878ddc88b..8f58e052697a 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -17,12 +17,6 @@
extern bool arch_hugetlb_migration_supported(struct hstate *h);
#endif
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr, unsigned long len)
-{
- return 0;
-}
-
static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_dcache_clean, &page->flags);
diff --git a/arch/ia64/include/asm/hugetlb.h b/arch/ia64/include/asm/hugetlb.h
index 36cc0396b214..6ef50b9a4bdf 100644
--- a/arch/ia64/include/asm/hugetlb.h
+++ b/arch/ia64/include/asm/hugetlb.h
@@ -20,6 +20,7 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
return (REGION_NUMBER(addr) == RGN_HPAGE ||
REGION_NUMBER((addr)+(len)-1) == RGN_HPAGE);
}
+#define is_hugepage_only_range is_hugepage_only_range
#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
diff --git a/arch/mips/include/asm/hugetlb.h b/arch/mips/include/asm/hugetlb.h
index 425bb6fc3bda..8b201e281f67 100644
--- a/arch/mips/include/asm/hugetlb.h
+++ b/arch/mips/include/asm/hugetlb.h
@@ -11,13 +11,6 @@
#include <asm/page.h>
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len)
-{
- return 0;
-}
-
#define __HAVE_ARCH_PREPARE_HUGEPAGE_RANGE
static inline int prepare_hugepage_range(struct file *file,
unsigned long addr,
diff --git a/arch/parisc/include/asm/hugetlb.h b/arch/parisc/include/asm/hugetlb.h
index 7cb595dcb7d7..411d9d867baa 100644
--- a/arch/parisc/include/asm/hugetlb.h
+++ b/arch/parisc/include/asm/hugetlb.h
@@ -12,12 +12,6 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep);
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len) {
- return 0;
-}
-
/*
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index bd6504c28c2f..b167c869d72d 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -30,6 +30,7 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
return slice_is_hugepage_only_range(mm, addr, len);
return 0;
}
+#define is_hugepage_only_range is_hugepage_only_range
#define __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
index 728a5db66597..866f6ae6467c 100644
--- a/arch/riscv/include/asm/hugetlb.h
+++ b/arch/riscv/include/asm/hugetlb.h
@@ -5,12 +5,6 @@
#include <asm-generic/hugetlb.h>
#include <asm/page.h>
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len) {
- return 0;
-}
-
static inline void arch_clear_hugepage_flags(struct page *page)
{
}
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index de8f0bf5f238..7d27ea96ec2f 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -21,13 +21,6 @@ pte_t huge_ptep_get(pte_t *ptep);
pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep);
-static inline bool is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len)
-{
- return false;
-}
-
/*
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
diff --git a/arch/sh/include/asm/hugetlb.h b/arch/sh/include/asm/hugetlb.h
index 6f025fe18146..536ad2cb8aa4 100644
--- a/arch/sh/include/asm/hugetlb.h
+++ b/arch/sh/include/asm/hugetlb.h
@@ -5,12 +5,6 @@
#include <asm/cacheflush.h>
#include <asm/page.h>
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len) {
- return 0;
-}
-
/*
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h
index 3963f80d1cb3..a056fe1119f5 100644
--- a/arch/sparc/include/asm/hugetlb.h
+++ b/arch/sparc/include/asm/hugetlb.h
@@ -20,12 +20,6 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep);
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len) {
- return 0;
-}
-
#define __HAVE_ARCH_HUGE_PTEP_CLEAR_FLUSH
static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index f65cfb48cfdd..cc98f79074d0 100644
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -7,12 +7,6 @@
#define hugepages_supported() boot_cpu_has(X86_FEATURE_PSE)
-static inline int is_hugepage_only_range(struct mm_struct *mm,
- unsigned long addr,
- unsigned long len) {
- return 0;
-}
-
static inline void arch_clear_hugepage_flags(struct page *page)
{
}
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 43a1cef8f0f1..c01c0c6f7fd4 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -591,6 +591,15 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h)
#include <asm/hugetlb.h>
+#ifndef is_hugepage_only_range
+static inline int is_hugepage_only_range(struct mm_struct *mm,
+ unsigned long addr, unsigned long len)
+{
+ return 0;
+}
+#define is_hugepage_only_range is_hugepage_only_range
+#endif
+
#ifndef arch_make_huge_pte
static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable)
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags()
2020-05-08 3:07 [PATCH V3 0/3] mm/hugetlb: Add some new generic fallbacks Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range() Anshuman Khandual
@ 2020-05-08 3:07 ` Anshuman Khandual
2020-05-11 20:22 ` Mike Kravetz
2 siblings, 1 reply; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-08 3:07 UTC (permalink / raw)
To: linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Anshuman Khandual, Thomas Bogendoerfer,
Borislav Petkov, Paul Walmsley, Thomas Gleixner, linux-arm-kernel,
Tony Luck, linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller, Mike Kravetz
There are multiple similar definitions for arch_clear_hugepage_flags() on
various platforms. Lets just add it's generic fallback definition for
platforms that do not override. This help reduce code duplication.
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: x86@kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/arm/include/asm/hugetlb.h | 1 +
arch/arm64/include/asm/hugetlb.h | 1 +
arch/ia64/include/asm/hugetlb.h | 4 ----
arch/mips/include/asm/hugetlb.h | 4 ----
arch/parisc/include/asm/hugetlb.h | 4 ----
arch/powerpc/include/asm/hugetlb.h | 4 ----
arch/riscv/include/asm/hugetlb.h | 4 ----
arch/s390/include/asm/hugetlb.h | 1 +
arch/sh/include/asm/hugetlb.h | 1 +
arch/sparc/include/asm/hugetlb.h | 4 ----
arch/x86/include/asm/hugetlb.h | 4 ----
include/linux/hugetlb.h | 5 +++++
12 files changed, 9 insertions(+), 28 deletions(-)
diff --git a/arch/arm/include/asm/hugetlb.h b/arch/arm/include/asm/hugetlb.h
index 9ecd516d1ff7..d02d6ca88e92 100644
--- a/arch/arm/include/asm/hugetlb.h
+++ b/arch/arm/include/asm/hugetlb.h
@@ -18,5 +18,6 @@ static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_dcache_clean, &page->flags);
}
+#define arch_clear_hugepage_flags arch_clear_hugepage_flags
#endif /* _ASM_ARM_HUGETLB_H */
diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index 8f58e052697a..94ba0c5bced2 100644
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -21,6 +21,7 @@ static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_dcache_clean, &page->flags);
}
+#define arch_clear_hugepage_flags arch_clear_hugepage_flags
extern pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable);
diff --git a/arch/ia64/include/asm/hugetlb.h b/arch/ia64/include/asm/hugetlb.h
index 6ef50b9a4bdf..7e46ebde8c0c 100644
--- a/arch/ia64/include/asm/hugetlb.h
+++ b/arch/ia64/include/asm/hugetlb.h
@@ -28,10 +28,6 @@ static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
{
}
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#include <asm-generic/hugetlb.h>
#endif /* _ASM_IA64_HUGETLB_H */
diff --git a/arch/mips/include/asm/hugetlb.h b/arch/mips/include/asm/hugetlb.h
index 8b201e281f67..10e3be870df7 100644
--- a/arch/mips/include/asm/hugetlb.h
+++ b/arch/mips/include/asm/hugetlb.h
@@ -75,10 +75,6 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
return changed;
}
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#include <asm-generic/hugetlb.h>
#endif /* __ASM_HUGETLB_H */
diff --git a/arch/parisc/include/asm/hugetlb.h b/arch/parisc/include/asm/hugetlb.h
index 411d9d867baa..a69cf9efb0c1 100644
--- a/arch/parisc/include/asm/hugetlb.h
+++ b/arch/parisc/include/asm/hugetlb.h
@@ -42,10 +42,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t pte, int dirty);
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#include <asm-generic/hugetlb.h>
#endif /* _ASM_PARISC64_HUGETLB_H */
diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index b167c869d72d..e6dfa63da552 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -61,10 +61,6 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep,
pte_t pte, int dirty);
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#include <asm-generic/hugetlb.h>
#else /* ! CONFIG_HUGETLB_PAGE */
diff --git a/arch/riscv/include/asm/hugetlb.h b/arch/riscv/include/asm/hugetlb.h
index 866f6ae6467c..a5c2ca1d1cd8 100644
--- a/arch/riscv/include/asm/hugetlb.h
+++ b/arch/riscv/include/asm/hugetlb.h
@@ -5,8 +5,4 @@
#include <asm-generic/hugetlb.h>
#include <asm/page.h>
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#endif /* _ASM_RISCV_HUGETLB_H */
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index 7d27ea96ec2f..9ddf4a43a590 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -39,6 +39,7 @@ static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_arch_1, &page->flags);
}
+#define arch_clear_hugepage_flags arch_clear_hugepage_flags
static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long sz)
diff --git a/arch/sh/include/asm/hugetlb.h b/arch/sh/include/asm/hugetlb.h
index 536ad2cb8aa4..ae4de7b89210 100644
--- a/arch/sh/include/asm/hugetlb.h
+++ b/arch/sh/include/asm/hugetlb.h
@@ -30,6 +30,7 @@ static inline void arch_clear_hugepage_flags(struct page *page)
{
clear_bit(PG_dcache_clean, &page->flags);
}
+#define arch_clear_hugepage_flags arch_clear_hugepage_flags
#include <asm-generic/hugetlb.h>
diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h
index a056fe1119f5..53838a173f62 100644
--- a/arch/sparc/include/asm/hugetlb.h
+++ b/arch/sparc/include/asm/hugetlb.h
@@ -47,10 +47,6 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
return changed;
}
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#define __HAVE_ARCH_HUGETLB_FREE_PGD_RANGE
void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
unsigned long end, unsigned long floor,
diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index cc98f79074d0..1721b1aadeb1 100644
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -7,8 +7,4 @@
#define hugepages_supported() boot_cpu_has(X86_FEATURE_PSE)
-static inline void arch_clear_hugepage_flags(struct page *page)
-{
-}
-
#endif /* _ASM_X86_HUGETLB_H */
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index c01c0c6f7fd4..04bc794becfc 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -600,6 +600,11 @@ static inline int is_hugepage_only_range(struct mm_struct *mm,
#define is_hugepage_only_range is_hugepage_only_range
#endif
+#ifndef arch_clear_hugepage_flags
+static inline void arch_clear_hugepage_flags(struct page *page) { }
+#define arch_clear_hugepage_flags arch_clear_hugepage_flags
+#endif
+
#ifndef arch_make_huge_pte
static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
struct page *page, int writable)
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET
2020-05-08 3:07 ` [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET Anshuman Khandual
@ 2020-05-08 22:09 ` Mike Kravetz
2020-05-11 4:02 ` Anshuman Khandual
0 siblings, 1 reply; 11+ messages in thread
From: Mike Kravetz @ 2020-05-08 22:09 UTC (permalink / raw)
To: Anshuman Khandual, linux-mm, akpm
Cc: Catalin Marinas, Will Deacon, linux-kernel, linux-arm-kernel
On 5/7/20 8:07 PM, Anshuman Khandual wrote:
> Platform specific huge_ptep_get() is required only when fetching the huge
> PTE involves more than just dereferencing the page table pointer. This is
> not the case on arm64 platform. Hence huge_ptep_pte() can be dropped along
> with it's __HAVE_ARCH_HUGE_PTEP_GET subscription. Before that, it updates
> the generic huge_ptep_get() with READ_ONCE() which will prevent known page
> table issues with THP on arm64.
>
> https://lore.kernel.org/r/1506527369-19535-1-git-send-email-will.deacon@arm.com/
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/include/asm/hugetlb.h | 6 ------
> include/asm-generic/hugetlb.h | 2 +-
> 2 files changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
> index 2eb6c234d594..b88878ddc88b 100644
> --- a/arch/arm64/include/asm/hugetlb.h
> +++ b/arch/arm64/include/asm/hugetlb.h
> @@ -17,12 +17,6 @@
> extern bool arch_hugetlb_migration_supported(struct hstate *h);
> #endif
>
> -#define __HAVE_ARCH_HUGE_PTEP_GET
> -static inline pte_t huge_ptep_get(pte_t *ptep)
> -{
> - return READ_ONCE(*ptep);
> -}
> -
> static inline int is_hugepage_only_range(struct mm_struct *mm,
> unsigned long addr, unsigned long len)
> {
> diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
> index 822f433ac95c..40f85decc2ee 100644
> --- a/include/asm-generic/hugetlb.h
> +++ b/include/asm-generic/hugetlb.h
> @@ -122,7 +122,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
> #ifndef __HAVE_ARCH_HUGE_PTEP_GET
> static inline pte_t huge_ptep_get(pte_t *ptep)
> {
> - return *ptep;
> + return READ_ONCE(*ptep);
> }
> #endif
I know you made this change in response to Will's comment. And, since
changes were made to consistently use READ_ONCE in arm64 code, it makes
sense for that architecture.
However, with this change to generic code, you introduce READ_ONCE to
other architectures where it was not used before. Could this possibly
introduce inconsistencies in their use of READ_ONCE? To be honest, I
am not very good at identifying any possible issues this could cause.
However, it does seem possible.
Will was nervous about dropping this from arm64. I'm just a little nervous
about adding it to other architectures.
--
Mike Kravetz
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range()
2020-05-08 3:07 ` [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range() Anshuman Khandual
@ 2020-05-08 22:22 ` Mike Kravetz
2020-05-11 3:14 ` Anshuman Khandual
0 siblings, 1 reply; 11+ messages in thread
From: Mike Kravetz @ 2020-05-08 22:22 UTC (permalink / raw)
To: Anshuman Khandual, linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Thomas Bogendoerfer, Borislav Petkov,
Paul Walmsley, Thomas Gleixner, linux-arm-kernel, Tony Luck,
linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller
On 5/7/20 8:07 PM, Anshuman Khandual wrote:
> There are multiple similar definitions for is_hugepage_only_range() on
> various platforms. Lets just add it's generic fallback definition for
> platforms that do not override. This help reduce code duplication.
>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: x86@kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-ia64@vger.kernel.org
> Cc: linux-mips@vger.kernel.org
> Cc: linux-parisc@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-s390@vger.kernel.org
> Cc: linux-sh@vger.kernel.org
> Cc: sparclinux@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-arch@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm/include/asm/hugetlb.h | 6 ------
> arch/arm64/include/asm/hugetlb.h | 6 ------
> arch/ia64/include/asm/hugetlb.h | 1 +
> arch/mips/include/asm/hugetlb.h | 7 -------
> arch/parisc/include/asm/hugetlb.h | 6 ------
> arch/powerpc/include/asm/hugetlb.h | 1 +
> arch/riscv/include/asm/hugetlb.h | 6 ------
> arch/s390/include/asm/hugetlb.h | 7 -------
> arch/sh/include/asm/hugetlb.h | 6 ------
> arch/sparc/include/asm/hugetlb.h | 6 ------
> arch/x86/include/asm/hugetlb.h | 6 ------
> include/linux/hugetlb.h | 9 +++++++++
> 12 files changed, 11 insertions(+), 56 deletions(-)
>
<snip>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 43a1cef8f0f1..c01c0c6f7fd4 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -591,6 +591,15 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h)
>
> #include <asm/hugetlb.h>
>
> +#ifndef is_hugepage_only_range
> +static inline int is_hugepage_only_range(struct mm_struct *mm,
> + unsigned long addr, unsigned long len)
> +{
> + return 0;
> +}
> +#define is_hugepage_only_range is_hugepage_only_range
> +#endif
> +
> #ifndef arch_make_huge_pte
> static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
> struct page *page, int writable)
>
Did you try building without CONFIG_HUGETLB_PAGE defined? I'm guessing
that you need a stub for is_hugepage_only_range(). Or, perhaps add this
to asm-generic/hugetlb.h?
--
Mike Kravetz
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range()
2020-05-08 22:22 ` Mike Kravetz
@ 2020-05-11 3:14 ` Anshuman Khandual
2020-05-11 18:52 ` Mike Kravetz
0 siblings, 1 reply; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-11 3:14 UTC (permalink / raw)
To: Mike Kravetz, linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Thomas Bogendoerfer, Borislav Petkov,
Paul Walmsley, Thomas Gleixner, linux-arm-kernel, Tony Luck,
linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller
On 05/09/2020 03:52 AM, Mike Kravetz wrote:
> On 5/7/20 8:07 PM, Anshuman Khandual wrote:
>> There are multiple similar definitions for is_hugepage_only_range() on
>> various platforms. Lets just add it's generic fallback definition for
>> platforms that do not override. This help reduce code duplication.
>>
>> Cc: Russell King <linux@armlinux.org.uk>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Tony Luck <tony.luck@intel.com>
>> Cc: Fenghua Yu <fenghua.yu@intel.com>
>> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
>> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
>> Cc: Helge Deller <deller@gmx.de>
>> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: Michael Ellerman <mpe@ellerman.id.au>
>> Cc: Paul Walmsley <paul.walmsley@sifive.com>
>> Cc: Palmer Dabbelt <palmer@dabbelt.com>
>> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
>> Cc: Vasily Gorbik <gor@linux.ibm.com>
>> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
>> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
>> Cc: Rich Felker <dalias@libc.org>
>> Cc: "David S. Miller" <davem@davemloft.net>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: Borislav Petkov <bp@alien8.de>
>> Cc: "H. Peter Anvin" <hpa@zytor.com>
>> Cc: Mike Kravetz <mike.kravetz@oracle.com>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: x86@kernel.org
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-ia64@vger.kernel.org
>> Cc: linux-mips@vger.kernel.org
>> Cc: linux-parisc@vger.kernel.org
>> Cc: linuxppc-dev@lists.ozlabs.org
>> Cc: linux-riscv@lists.infradead.org
>> Cc: linux-s390@vger.kernel.org
>> Cc: linux-sh@vger.kernel.org
>> Cc: sparclinux@vger.kernel.org
>> Cc: linux-mm@kvack.org
>> Cc: linux-arch@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> arch/arm/include/asm/hugetlb.h | 6 ------
>> arch/arm64/include/asm/hugetlb.h | 6 ------
>> arch/ia64/include/asm/hugetlb.h | 1 +
>> arch/mips/include/asm/hugetlb.h | 7 -------
>> arch/parisc/include/asm/hugetlb.h | 6 ------
>> arch/powerpc/include/asm/hugetlb.h | 1 +
>> arch/riscv/include/asm/hugetlb.h | 6 ------
>> arch/s390/include/asm/hugetlb.h | 7 -------
>> arch/sh/include/asm/hugetlb.h | 6 ------
>> arch/sparc/include/asm/hugetlb.h | 6 ------
>> arch/x86/include/asm/hugetlb.h | 6 ------
>> include/linux/hugetlb.h | 9 +++++++++
>> 12 files changed, 11 insertions(+), 56 deletions(-)
>>
> <snip>
>> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
>> index 43a1cef8f0f1..c01c0c6f7fd4 100644
>> --- a/include/linux/hugetlb.h
>> +++ b/include/linux/hugetlb.h
>> @@ -591,6 +591,15 @@ static inline unsigned int blocks_per_huge_page(struct hstate *h)
>>
>> #include <asm/hugetlb.h>
>>
>> +#ifndef is_hugepage_only_range
>> +static inline int is_hugepage_only_range(struct mm_struct *mm,
>> + unsigned long addr, unsigned long len)
>> +{
>> + return 0;
>> +}
>> +#define is_hugepage_only_range is_hugepage_only_range
>> +#endif
>> +
>> #ifndef arch_make_huge_pte
>> static inline pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
>> struct page *page, int writable)
>>
>
> Did you try building without CONFIG_HUGETLB_PAGE defined? I'm guessing
Yes I did for multiple platforms (s390, arm64, ia64, x86, powerpc etc).
> that you need a stub for is_hugepage_only_range(). Or, perhaps add this
> to asm-generic/hugetlb.h?
>
There is already a stub (include/linux/hugetlb.h) when !CONFIG_HUGETLB_PAGE.
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET
2020-05-08 22:09 ` Mike Kravetz
@ 2020-05-11 4:02 ` Anshuman Khandual
2020-05-11 18:49 ` Mike Kravetz
0 siblings, 1 reply; 11+ messages in thread
From: Anshuman Khandual @ 2020-05-11 4:02 UTC (permalink / raw)
To: Mike Kravetz, linux-mm, akpm
Cc: Catalin Marinas, Will Deacon, linux-kernel, linux-arm-kernel
On 05/09/2020 03:39 AM, Mike Kravetz wrote:
> On 5/7/20 8:07 PM, Anshuman Khandual wrote:
>> Platform specific huge_ptep_get() is required only when fetching the huge
>> PTE involves more than just dereferencing the page table pointer. This is
>> not the case on arm64 platform. Hence huge_ptep_pte() can be dropped along
>> with it's __HAVE_ARCH_HUGE_PTEP_GET subscription. Before that, it updates
>> the generic huge_ptep_get() with READ_ONCE() which will prevent known page
>> table issues with THP on arm64.
>>
>> https://lore.kernel.org/r/1506527369-19535-1-git-send-email-will.deacon@arm.com/
>>
>> Cc: Catalin Marinas <catalin.marinas@arm.com>
>> Cc: Will Deacon <will@kernel.org>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-mm@kvack.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
>> ---
>> arch/arm64/include/asm/hugetlb.h | 6 ------
>> include/asm-generic/hugetlb.h | 2 +-
>> 2 files changed, 1 insertion(+), 7 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
>> index 2eb6c234d594..b88878ddc88b 100644
>> --- a/arch/arm64/include/asm/hugetlb.h
>> +++ b/arch/arm64/include/asm/hugetlb.h
>> @@ -17,12 +17,6 @@
>> extern bool arch_hugetlb_migration_supported(struct hstate *h);
>> #endif
>>
>> -#define __HAVE_ARCH_HUGE_PTEP_GET
>> -static inline pte_t huge_ptep_get(pte_t *ptep)
>> -{
>> - return READ_ONCE(*ptep);
>> -}
>> -
>> static inline int is_hugepage_only_range(struct mm_struct *mm,
>> unsigned long addr, unsigned long len)
>> {
>> diff --git a/include/asm-generic/hugetlb.h b/include/asm-generic/hugetlb.h
>> index 822f433ac95c..40f85decc2ee 100644
>> --- a/include/asm-generic/hugetlb.h
>> +++ b/include/asm-generic/hugetlb.h
>> @@ -122,7 +122,7 @@ static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,
>> #ifndef __HAVE_ARCH_HUGE_PTEP_GET
>> static inline pte_t huge_ptep_get(pte_t *ptep)
>> {
>> - return *ptep;
>> + return READ_ONCE(*ptep);
>> }
>> #endif
>
> I know you made this change in response to Will's comment. And, since
> changes were made to consistently use READ_ONCE in arm64 code, it makes
> sense for that architecture.
>
> However, with this change to generic code, you introduce READ_ONCE to
> other architectures where it was not used before. Could this possibly
> introduce inconsistencies in their use of READ_ONCE? To be honest, I
> am not very good at identifying any possible issues this could cause.
> However, it does seem possible.
Could you please give some more details. Is there any particular problem
which might be caused by this new READ_ONCE() here, that you you are
concerned about. READ_ONCE() is already getting used in multiple places
in core MM which can not be configured out (like mm/gup.c). It is getting
used in core HugeTLB (mm/hugetlb.c) as well. AFAICS, there is no standard
for using READ_ONCE() while walking page tables entries. We have examples
in core MM for both ways.
>
> Will was nervous about dropping this from arm64. I'm just a little nervous
> about adding it to other architectures.
>
AFAICS, __HAVE_ARCH_HUGE_PTEP_GET should be used on a platform only when
a HugeTLB entry could not constructed by dereferencing a page table entry
as in the case with ARM (32 bit). Using READ_ONCE() while dereferencing is
really not a special case that will need __HAVE_ARCH_HUGE_PTEP_GET. Moving
READ_ONCE() into generic definition solves the problem while also taking
care of a known problem on arm64. IMHO, it seems like the right thing to
do unless there is another problem that pops up some where else because of
READ_ONCE().
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET
2020-05-11 4:02 ` Anshuman Khandual
@ 2020-05-11 18:49 ` Mike Kravetz
0 siblings, 0 replies; 11+ messages in thread
From: Mike Kravetz @ 2020-05-11 18:49 UTC (permalink / raw)
To: Anshuman Khandual, linux-mm, akpm
Cc: Catalin Marinas, Will Deacon, linux-kernel, linux-arm-kernel
On 5/10/20 9:02 PM, Anshuman Khandual wrote:
> On 05/09/2020 03:39 AM, Mike Kravetz wrote:
>> On 5/7/20 8:07 PM, Anshuman Khandual wrote:
>> I know you made this change in response to Will's comment. And, since
>> changes were made to consistently use READ_ONCE in arm64 code, it makes
>> sense for that architecture.
>>
>> However, with this change to generic code, you introduce READ_ONCE to
>> other architectures where it was not used before. Could this possibly
>> introduce inconsistencies in their use of READ_ONCE? To be honest, I
>> am not very good at identifying any possible issues this could cause.
>> However, it does seem possible.
>
> Could you please give some more details. Is there any particular problem
> which might be caused by this new READ_ONCE() here, that you you are
> concerned about. READ_ONCE() is already getting used in multiple places
> in core MM which can not be configured out (like mm/gup.c). It is getting
> used in core HugeTLB (mm/hugetlb.c) as well. AFAICS, there is no standard
> for using READ_ONCE() while walking page tables entries. We have examples
> in core MM for both ways.
>
>>
>> Will was nervous about dropping this from arm64. I'm just a little nervous
>> about adding it to other architectures.
>>
> AFAICS, __HAVE_ARCH_HUGE_PTEP_GET should be used on a platform only when
> a HugeTLB entry could not constructed by dereferencing a page table entry
> as in the case with ARM (32 bit). Using READ_ONCE() while dereferencing is
> really not a special case that will need __HAVE_ARCH_HUGE_PTEP_GET. Moving
> READ_ONCE() into generic definition solves the problem while also taking
> care of a known problem on arm64. IMHO, it seems like the right thing to
> do unless there is another problem that pops up some where else because of
> READ_ONCE().
I have no specific concerns or objection. After thinking about it some more,
I do not see how adding the READ_ONCE could cause any issues.
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
--
Mike Kravetz
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range()
2020-05-11 3:14 ` Anshuman Khandual
@ 2020-05-11 18:52 ` Mike Kravetz
0 siblings, 0 replies; 11+ messages in thread
From: Mike Kravetz @ 2020-05-11 18:52 UTC (permalink / raw)
To: Anshuman Khandual, linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Thomas Bogendoerfer, Borislav Petkov,
Paul Walmsley, Thomas Gleixner, linux-arm-kernel, Tony Luck,
linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller
On 5/10/20 8:14 PM, Anshuman Khandual wrote:
> On 05/09/2020 03:52 AM, Mike Kravetz wrote:
>> On 5/7/20 8:07 PM, Anshuman Khandual wrote:
>>
>> Did you try building without CONFIG_HUGETLB_PAGE defined? I'm guessing
>
> Yes I did for multiple platforms (s390, arm64, ia64, x86, powerpc etc).
>
>> that you need a stub for is_hugepage_only_range(). Or, perhaps add this
>> to asm-generic/hugetlb.h?
>>
> There is already a stub (include/linux/hugetlb.h) when !CONFIG_HUGETLB_PAGE.
>
Thanks! I missed that stub in the existing code. I like the removal of
redundant code.
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
--
Mike Kravetz
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^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags()
2020-05-08 3:07 ` [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags() Anshuman Khandual
@ 2020-05-11 20:22 ` Mike Kravetz
0 siblings, 0 replies; 11+ messages in thread
From: Mike Kravetz @ 2020-05-11 20:22 UTC (permalink / raw)
To: Anshuman Khandual, linux-mm, akpm
Cc: Rich Felker, linux-ia64, linux-sh, Catalin Marinas,
Heiko Carstens, linux-kernel, James E.J. Bottomley,
Paul Mackerras, H. Peter Anvin, sparclinux, linux-riscv,
Will Deacon, linux-arch, linux-s390, Yoshinori Sato,
Michael Ellerman, Helge Deller, x86, Russell King,
Christian Borntraeger, Ingo Molnar, Benjamin Herrenschmidt,
Fenghua Yu, Vasily Gorbik, Thomas Bogendoerfer, Borislav Petkov,
Paul Walmsley, Thomas Gleixner, linux-arm-kernel, Tony Luck,
linux-parisc, linux-mips, Palmer Dabbelt, linuxppc-dev,
David S. Miller
On 5/7/20 8:07 PM, Anshuman Khandual wrote:
> There are multiple similar definitions for arch_clear_hugepage_flags() on
> various platforms. Lets just add it's generic fallback definition for
> platforms that do not override. This help reduce code duplication.
>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: x86@kernel.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-ia64@vger.kernel.org
> Cc: linux-mips@vger.kernel.org
> Cc: linux-parisc@vger.kernel.org
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-s390@vger.kernel.org
> Cc: linux-sh@vger.kernel.org
> Cc: sparclinux@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-arch@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Thanks!
Removing duplicate code is good.
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
--
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^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2020-05-11 20:24 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-05-08 3:07 [PATCH V3 0/3] mm/hugetlb: Add some new generic fallbacks Anshuman Khandual
2020-05-08 3:07 ` [PATCH V3 1/3] arm64/mm: Drop __HAVE_ARCH_HUGE_PTEP_GET Anshuman Khandual
2020-05-08 22:09 ` Mike Kravetz
2020-05-11 4:02 ` Anshuman Khandual
2020-05-11 18:49 ` Mike Kravetz
2020-05-08 3:07 ` [PATCH V3 2/3] mm/hugetlb: Define a generic fallback for is_hugepage_only_range() Anshuman Khandual
2020-05-08 22:22 ` Mike Kravetz
2020-05-11 3:14 ` Anshuman Khandual
2020-05-11 18:52 ` Mike Kravetz
2020-05-08 3:07 ` [PATCH V3 3/3] mm/hugetlb: Define a generic fallback for arch_clear_hugepage_flags() Anshuman Khandual
2020-05-11 20:22 ` Mike Kravetz
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