diff mbox series

[4/8] asm-generic: pgalloc: provide generic pmd_alloc_one() and pmd_free_one()

Message ID 20200627143453.31835-5-rppt@kernel.org
State Not Applicable
Headers show
Series mm: cleanup usage of <asm/pgalloc.h> | expand

Commit Message

Mike Rapoport June 27, 2020, 2:34 p.m. UTC 
From: Mike Rapoport <rppt@linux.ibm.com>

For most architectures that support >2 levels of page tables,
pmd_alloc_one() is a wrapper for __get_free_pages(), sometimes with
__GFP_ZERO and sometimes followed by memset(0) instead.

More elaborate versions on arm64 and x86 account memory for the user page
tables and call to pgtable_pmd_page_ctor() as the part of PMD page
initialization.

Move the arm64 version to include/asm-generic/pgalloc.h and use the generic
version on several architectures.

The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
not enabled, so there is no functional change for most architectures except
of the addition of __GFP_ACCOUNT for allocation of user page tables.

The pmd_free() is a wrapper for free_page() in all the cases, so no
functional change here.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
 arch/alpha/include/asm/pgalloc.h     | 15 +---------
 arch/arm/include/asm/pgalloc.h       | 11 -------
 arch/arm64/include/asm/pgalloc.h     | 27 +----------------
 arch/ia64/include/asm/pgalloc.h      | 10 -------
 arch/mips/include/asm/pgalloc.h      |  8 ++----
 arch/parisc/include/asm/pgalloc.h    | 11 ++-----
 arch/riscv/include/asm/pgalloc.h     | 13 +--------
 arch/sh/include/asm/pgalloc.h        |  3 ++
 arch/um/include/asm/pgalloc.h        |  8 +-----
 arch/um/include/asm/pgtable-3level.h |  3 --
 arch/um/kernel/mem.c                 | 12 --------
 arch/x86/include/asm/pgalloc.h       | 26 +----------------
 include/asm-generic/pgalloc.h        | 43 ++++++++++++++++++++++++++++
 13 files changed, 55 insertions(+), 135 deletions(-)

Comments

Matthew Wilcox (Oracle) June 27, 2020, 7:03 p.m. UTC | #1 
On Sat, Jun 27, 2020 at 05:34:49PM +0300, Mike Rapoport wrote:
> More elaborate versions on arm64 and x86 account memory for the user page
> tables and call to pgtable_pmd_page_ctor() as the part of PMD page
> initialization.
> 
> Move the arm64 version to include/asm-generic/pgalloc.h and use the generic
> version on several architectures.
> 
> The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
> not enabled, so there is no functional change for most architectures except
> of the addition of __GFP_ACCOUNT for allocation of user page tables.

Thanks for including this line; it reminded me that we're not setting
the PageTable flag on the page, nor accounting it to the zone page stats.
Hope you don't mind me tagging a patch to do that on as 9/8.

We could also do with a pud_page_[cd]tor and maybe even p4d/pgd versions.
But that brings me to the next question -- could/should some of this
be moved over to asm-generic/pgalloc.h?  The ctor/dtor aren't called
from anywhere else, and there's value to reducing the total amount of
code in mm.h, but then there's also value to keeping all the ifdef
ARCH_ENABLE_SPLIT_PMD_PTLOCK code together too.  So I'm a bit torn.
What do you think?
Mike Rapoport June 28, 2020, 7:10 a.m. UTC | #2 
On Sat, Jun 27, 2020 at 08:03:04PM +0100, Matthew Wilcox wrote:
> On Sat, Jun 27, 2020 at 05:34:49PM +0300, Mike Rapoport wrote:
> > More elaborate versions on arm64 and x86 account memory for the user page
> > tables and call to pgtable_pmd_page_ctor() as the part of PMD page
> > initialization.
> > 
> > Move the arm64 version to include/asm-generic/pgalloc.h and use the generic
> > version on several architectures.
> > 
> > The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
> > not enabled, so there is no functional change for most architectures except
> > of the addition of __GFP_ACCOUNT for allocation of user page tables.
> 
> Thanks for including this line; it reminded me that we're not setting
> the PageTable flag on the page, nor accounting it to the zone page stats.
> Hope you don't mind me tagging a patch to do that on as 9/8.
> 
> We could also do with a pud_page_[cd]tor and maybe even p4d/pgd versions.
> But that brings me to the next question -- could/should some of this
> be moved over to asm-generic/pgalloc.h?  The ctor/dtor aren't called
> from anywhere else, and there's value to reducing the total amount of
> code in mm.h, but then there's also value to keeping all the ifdef
> ARCH_ENABLE_SPLIT_PMD_PTLOCK code together too.  So I'm a bit torn.
> What do you think?

There are arhcitectures that don't use asm-generic/pgalloc.h but rather
have their own, sometimes completely different, versoins of these
funcitons.

I've tried adding linux/pgalloc.h, but I've ended up with contradicting
need to include asm/pgalloc.h before the generic code for some
architecures or after the generic code for others :)

I think let's leave it in mm.h for now, maybe after several more cleaups
we could do better.
Mike Rapoport June 29, 2020, 3:59 p.m. UTC | #3 
On Sat, Jun 27, 2020 at 08:03:04PM +0100, Matthew Wilcox wrote:
> On Sat, Jun 27, 2020 at 05:34:49PM +0300, Mike Rapoport wrote:
> > More elaborate versions on arm64 and x86 account memory for the user page
> > tables and call to pgtable_pmd_page_ctor() as the part of PMD page
> > initialization.
> > 
> > Move the arm64 version to include/asm-generic/pgalloc.h and use the generic
> > version on several architectures.
> > 
> > The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
> > not enabled, so there is no functional change for most architectures except
> > of the addition of __GFP_ACCOUNT for allocation of user page tables.
> 
> Thanks for including this line; it reminded me that we're not setting
> the PageTable flag on the page, nor accounting it to the zone page stats.
> Hope you don't mind me tagging a patch to do that on as 9/8.

We also never set PageTable flag for early page tables and for the page
tables allocated directly with get_free_page(), e.g PTI, KASAN.

> We could also do with a pud_page_[cd]tor and maybe even p4d/pgd versions.
> But that brings me to the next question -- could/should some of this
> be moved over to asm-generic/pgalloc.h?  The ctor/dtor aren't called
> from anywhere else, and there's value to reducing the total amount of
> code in mm.h, but then there's also value to keeping all the ifdef
> ARCH_ENABLE_SPLIT_PMD_PTLOCK code together too.  So I'm a bit torn.
> What do you think?
diff mbox series

Patch

diff --git a/arch/alpha/include/asm/pgalloc.h b/arch/alpha/include/asm/pgalloc.h
index a1a29f60934c..4834cd52e9d0 100644
--- a/arch/alpha/include/asm/pgalloc.h
+++ b/arch/alpha/include/asm/pgalloc.h
@@ -5,7 +5,7 @@ 
 #include <linux/mm.h>
 #include <linux/mmzone.h>
 
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#include <asm-generic/pgalloc.h>
 
 /*      
  * Allocate and free page tables. The xxx_kernel() versions are
@@ -40,17 +40,4 @@  pgd_free(struct mm_struct *mm, pgd_t *pgd)
 	free_page((unsigned long)pgd);
 }
 
-static inline pmd_t *
-pmd_alloc_one(struct mm_struct *mm, unsigned long address)
-{
-	pmd_t *ret = (pmd_t *)__get_free_page(GFP_PGTABLE_USER);
-	return ret;
-}
-
-static inline void
-pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_page((unsigned long)pmd);
-}
-
 #endif /* _ALPHA_PGALLOC_H */
diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
index 069da393110c..c5bdfd404ea5 100644
--- a/arch/arm/include/asm/pgalloc.h
+++ b/arch/arm/include/asm/pgalloc.h
@@ -22,17 +22,6 @@ 
 
 #ifdef CONFIG_ARM_LPAE
 
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	return (pmd_t *)get_zeroed_page(GFP_KERNEL);
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
-	free_page((unsigned long)pmd);
-}
-
 static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 {
 	set_pud(pud, __pud(__pa(pmd) | PMD_TYPE_TABLE));
diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 58e93583ddb6..7246d0a662e1 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -13,37 +13,12 @@ 
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#include <asm-generic/pgalloc.h>
 
 #define PGD_SIZE	(PTRS_PER_PGD * sizeof(pgd_t))
 
 #if CONFIG_PGTABLE_LEVELS > 2
 
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	gfp_t gfp = GFP_PGTABLE_USER;
-	struct page *page;
-
-	if (mm == &init_mm)
-		gfp = GFP_PGTABLE_KERNEL;
-
-	page = alloc_page(gfp);
-	if (!page)
-		return NULL;
-	if (!pgtable_pmd_page_ctor(page)) {
-		__free_page(page);
-		return NULL;
-	}
-	return page_address(page);
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmdp)
-{
-	BUG_ON((unsigned long)pmdp & (PAGE_SIZE-1));
-	pgtable_pmd_page_dtor(virt_to_page(pmdp));
-	free_page((unsigned long)pmdp);
-}
-
 static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot)
 {
 	set_pud(pudp, __pud(__phys_to_pud_val(pmdp) | prot));
diff --git a/arch/ia64/include/asm/pgalloc.h b/arch/ia64/include/asm/pgalloc.h
index 2a3050345099..5da1fc76477b 100644
--- a/arch/ia64/include/asm/pgalloc.h
+++ b/arch/ia64/include/asm/pgalloc.h
@@ -59,16 +59,6 @@  pud_populate(struct mm_struct *mm, pud_t * pud_entry, pmd_t * pmd)
 	pud_val(*pud_entry) = __pa(pmd);
 }
 
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	return (pmd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_page((unsigned long)pmd);
-}
-
 #define __pmd_free_tlb(tlb, pmd, address)	pmd_free((tlb)->mm, pmd)
 
 static inline void
diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
index fa77cb71f303..eed1b3e8c642 100644
--- a/arch/mips/include/asm/pgalloc.h
+++ b/arch/mips/include/asm/pgalloc.h
@@ -13,7 +13,8 @@ 
 #include <linux/mm.h>
 #include <linux/sched.h>
 
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#define __HAVE_ARCH_PMD_ALLOC_ONE
+#include <asm-generic/pgalloc.h>
 
 static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
 	pte_t *pte)
@@ -70,11 +71,6 @@  static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
 	return pmd;
 }
 
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_pages((unsigned long)pmd, PMD_ORDER);
-}
-
 #define __pmd_free_tlb(tlb, x, addr)	pmd_free((tlb)->mm, x)
 
 #endif
diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index 9ac74da256b8..689766b914ed 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -10,7 +10,8 @@ 
 
 #include <asm/cache.h>
 
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#define __HAVE_ARCH_PMD_FREE
+#include <asm-generic/pgalloc.h>
 
 /* Allocate the top level pgd (page directory)
  *
@@ -65,14 +66,6 @@  static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
 			(__u32)(__pa((unsigned long)pmd) >> PxD_VALUE_SHIFT)));
 }
 
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
-{
-	pmd_t *pmd = (pmd_t *)__get_free_pages(GFP_KERNEL, PMD_ORDER);
-	if (pmd)
-		memset(pmd, 0, PAGE_SIZE<<PMD_ORDER);
-	return pmd;
-}
-
 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
 {
 	if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) {
diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index 3f601ee8233f..8d3135f05b8e 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -11,7 +11,7 @@ 
 #include <asm/tlb.h>
 
 #ifdef CONFIG_MMU
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#include <asm-generic/pgalloc.h>
 
 static inline void pmd_populate_kernel(struct mm_struct *mm,
 	pmd_t *pmd, pte_t *pte)
@@ -62,17 +62,6 @@  static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 
 #ifndef __PAGETABLE_PMD_FOLDED
 
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	return (pmd_t *)__get_free_page(
-		GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_ZERO);
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_page((unsigned long)pmd);
-}
-
 #define __pmd_free_tlb(tlb, pmd, addr)  pmd_free((tlb)->mm, pmd)
 
 #endif /* __PAGETABLE_PMD_FOLDED */
diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index 22d968bfe9bb..59263df76f51 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -3,6 +3,9 @@ 
 #define __ASM_SH_PGALLOC_H
 
 #include <asm/page.h>
+
+#define __HAVE_ARCH_PMD_ALLOC_ONE
+#define __HAVE_ARCH_PMD_FREE
 #include <asm-generic/pgalloc.h>
 
 extern pgd_t *pgd_alloc(struct mm_struct *);
diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h
index 881e76da1938..bdde433dbdec 100644
--- a/arch/um/include/asm/pgalloc.h
+++ b/arch/um/include/asm/pgalloc.h
@@ -10,7 +10,7 @@ 
 
 #include <linux/mm.h>
 
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#include <asm-generic/pgalloc.h>
 
 #define pmd_populate_kernel(mm, pmd, pte) \
 	set_pmd(pmd, __pmd(_PAGE_TABLE + (unsigned long) __pa(pte)))
@@ -34,12 +34,6 @@  do {							\
 } while (0)
 
 #ifdef CONFIG_3_LEVEL_PGTABLES
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	free_page((unsigned long)pmd);
-}
-
 #define __pmd_free_tlb(tlb,x, address)   tlb_remove_page((tlb),virt_to_page(x))
 #endif
 
diff --git a/arch/um/include/asm/pgtable-3level.h b/arch/um/include/asm/pgtable-3level.h
index 36f452957cef..7e6a4180db9d 100644
--- a/arch/um/include/asm/pgtable-3level.h
+++ b/arch/um/include/asm/pgtable-3level.h
@@ -78,9 +78,6 @@  static inline void pgd_mkuptodate(pgd_t pgd) { pgd_val(pgd) &= ~_PAGE_NEWPAGE; }
 #define set_pmd(pmdptr, pmdval) (*(pmdptr) = (pmdval))
 #endif
 
-struct mm_struct;
-extern pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address);
-
 static inline void pud_clear (pud_t *pud)
 {
 	set_pud(pud, __pud(_PAGE_NEWPAGE));
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index c2ff76c8981e..a4accb14cbd5 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -201,18 +201,6 @@  void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 	free_page((unsigned long) pgd);
 }
 
-#ifdef CONFIG_3_LEVEL_PGTABLES
-pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
-{
-	pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL);
-
-	if (pmd)
-		memset(pmd, 0, PAGE_SIZE);
-
-	return pmd;
-}
-#endif
-
 void *uml_kmalloc(int size, int flags)
 {
 	return kmalloc(size, flags);
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index 29aa7859bdee..25feaa117c40 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h
@@ -7,7 +7,7 @@ 
 #include <linux/pagemap.h>
 
 #define __HAVE_ARCH_PTE_ALLOC_ONE
-#include <asm-generic/pgalloc.h>	/* for pte_{alloc,free}_one */
+#include <asm-generic/pgalloc.h>
 
 static inline int  __paravirt_pgd_alloc(struct mm_struct *mm) { return 0; }
 
@@ -86,30 +86,6 @@  static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
 #define pmd_pgtable(pmd) pmd_page(pmd)
 
 #if CONFIG_PGTABLE_LEVELS > 2
-static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	struct page *page;
-	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO;
-
-	if (mm == &init_mm)
-		gfp &= ~__GFP_ACCOUNT;
-	page = alloc_pages(gfp, 0);
-	if (!page)
-		return NULL;
-	if (!pgtable_pmd_page_ctor(page)) {
-		__free_pages(page, 0);
-		return NULL;
-	}
-	return (pmd_t *)page_address(page);
-}
-
-static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
-{
-	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
-	pgtable_pmd_page_dtor(virt_to_page(pmd));
-	free_page((unsigned long)pmd);
-}
-
 extern void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);
 
 static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
diff --git a/include/asm-generic/pgalloc.h b/include/asm-generic/pgalloc.h
index 73f7421413cb..1bc027891a00 100644
--- a/include/asm-generic/pgalloc.h
+++ b/include/asm-generic/pgalloc.h
@@ -102,6 +102,49 @@  static inline void pte_free(struct mm_struct *mm, struct page *pte_page)
 	__free_page(pte_page);
 }
 
+
+#if CONFIG_PGTABLE_LEVELS > 2
+
+#ifndef __HAVE_ARCH_PMD_ALLOC_ONE
+/**
+ * pmd_alloc_one - allocate a page for PMD-level page table
+ * @mm: the mm_struct of the current context
+ *
+ * Allocates a page and runs the pgtable_pmd_page_ctor().
+ * Allocations use %GFP_PGTABLE_USER in user context and
+ * %GFP_PGTABLE_KERNEL in kernel context.
+ *
+ * Return: pointer to the allocated memory or %NULL on error
+ */
+static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
+{
+	struct page *page;
+	gfp_t gfp = GFP_PGTABLE_USER;
+
+	if (mm == &init_mm)
+		gfp = GFP_PGTABLE_KERNEL;
+	page = alloc_pages(gfp, 0);
+	if (!page)
+		return NULL;
+	if (!pgtable_pmd_page_ctor(page)) {
+		__free_pages(page, 0);
+		return NULL;
+	}
+	return (pmd_t *)page_address(page);
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMD_FREE
+static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
+{
+	BUG_ON((unsigned long)pmd & (PAGE_SIZE-1));
+	pgtable_pmd_page_dtor(virt_to_page(pmd));
+	free_page((unsigned long)pmd);
+}
+#endif
+
+#endif /* CONFIG_PGTABLE_LEVELS > 2 */
+
 #endif /* CONFIG_MMU */
 
 #endif /* __ASM_GENERIC_PGALLOC_H */