* [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: Anshuman Khandual, Russell King, Catalin Marinas, Will Deacon,
Tony Luck, Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, Mike Kravetz, x86,
linux-arm-kernel, linux-ia64, linux-mips, linux-parisc,
linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
linux-arch, linux-kernel
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
^ 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: Anshuman Khandual, Catalin Marinas, Will Deacon,
linux-arm-kernel, linux-kernel
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
^ 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: Anshuman Khandual, Russell King, Catalin Marinas, Will Deacon,
Tony Luck, Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, Mike Kravetz, x86,
linux-arm-kernel, linux-ia64, linux-mips, linux-parisc,
linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
linux-arch, linux-kernel
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
^ 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: Anshuman Khandual, Russell King, Catalin Marinas, Will Deacon,
Tony Luck, Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, Mike Kravetz, x86,
linux-arm-kernel, linux-ia64, linux-mips, linux-parisc,
linuxppc-dev, linux-riscv, linux-s390, linux-sh, sparclinux,
linux-arch, linux-kernel
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
^ 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-arm-kernel, linux-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
^ 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: Russell King, Catalin Marinas, Will Deacon, Tony Luck,
Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, x86, linux-arm-kernel,
linux-ia64, linux-mips, linux-parisc, linuxppc-dev, linux-riscv,
linux-s390, linux-sh, sparclinux, linux-arch, linux-kernel
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
^ 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: Russell King, Catalin Marinas, Will Deacon, Tony Luck,
Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, x86, linux-arm-kernel,
linux-ia64, linux-mips, linux-parisc, linuxppc-dev, linux-riscv,
linux-s390, linux-sh, sparclinux, linux-arch, linux-kernel
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.
^ 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-arm-kernel, linux-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().
^ 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-arm-kernel, linux-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
^ 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: Russell King, Catalin Marinas, Will Deacon, Tony Luck,
Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, x86, linux-arm-kernel,
linux-ia64, linux-mips, linux-parisc, linuxppc-dev, linux-riscv,
linux-s390, linux-sh, sparclinux, linux-arch, linux-kernel
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
^ 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: Russell King, Catalin Marinas, Will Deacon, Tony Luck,
Fenghua Yu, Thomas Bogendoerfer, James E.J. Bottomley,
Helge Deller, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Paul Walmsley, Palmer Dabbelt, Heiko Carstens,
Vasily Gorbik, Christian Borntraeger, Yoshinori Sato,
Rich Felker, David S. Miller, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, H. Peter Anvin, x86, linux-arm-kernel,
linux-ia64, linux-mips, linux-parisc, linuxppc-dev, linux-riscv,
linux-s390, linux-sh, sparclinux, linux-arch, linux-kernel
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>
--
Mike Kravetz
^ 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
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).