lkml.org 
[lkml]   [2017]   [Mar]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:x86/mm] mm/gup: Implement the dev_pagemap() logic in the generic get_user_pages_fast() function
Commit-ID:  b59f65fa076a8eac2ff3a8ab7f8e1705b9fa86cb
Gitweb: http://git.kernel.org/tip/b59f65fa076a8eac2ff3a8ab7f8e1705b9fa86cb
Author: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
AuthorDate: Thu, 16 Mar 2017 18:26:53 +0300
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Sat, 18 Mar 2017 09:48:02 +0100

mm/gup: Implement the dev_pagemap() logic in the generic get_user_pages_fast() function

This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

Prepare generic GUP_fast() to handle dev_pagemap(). At the moment, it's
only implemented on x86. On non-x86, the new code will be compiled out.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-6-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
include/linux/mm.h | 4 +++
mm/gup.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
2 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5f01c88..e197d3c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -430,6 +430,10 @@ static inline int pud_devmap(pud_t pud)
{
return 0;
}
+static inline int pgd_devmap(pgd_t pgd)
+{
+ return 0;
+}
#endif

/*
diff --git a/mm/gup.c b/mm/gup.c
index 2b6cd357..e3d1e80 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1200,12 +1200,23 @@ static inline pte_t gup_get_pte(pte_t *ptep)
}
#endif

+static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)
+{
+ while ((*nr) - nr_start) {
+ struct page *page = pages[--(*nr)];
+
+ ClearPageReferenced(page);
+ put_page(page);
+ }
+}
+
#ifdef __HAVE_ARCH_PTE_SPECIAL
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
int write, struct page **pages, int *nr)
{
+ struct dev_pagemap *pgmap = NULL;
+ int nr_start = *nr, ret = 0;
pte_t *ptep, *ptem;
- int ret = 0;

ptem = ptep = pte_offset_map(&pmd, addr);
do {
@@ -1222,7 +1233,13 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
if (!pte_access_permitted(pte, write))
goto pte_unmap;

- if (pte_special(pte))
+ if (pte_devmap(pte)) {
+ pgmap = get_dev_pagemap(pte_pfn(pte), pgmap);
+ if (unlikely(!pgmap)) {
+ undo_dev_pagemap(nr, nr_start, pages);
+ goto pte_unmap;
+ }
+ } else if (pte_special(pte))
goto pte_unmap;

VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
@@ -1239,6 +1256,7 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,

VM_BUG_ON_PAGE(compound_head(page) != head, page);

+ put_dev_pagemap(pgmap);
SetPageReferenced(page);
pages[*nr] = page;
(*nr)++;
@@ -1269,6 +1287,64 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
}
#endif /* __HAVE_ARCH_PTE_SPECIAL */

+#ifdef __HAVE_ARCH_PTE_DEVMAP
+static int __gup_device_huge(unsigned long pfn, unsigned long addr,
+ unsigned long end, struct page **pages, int *nr)
+{
+ int nr_start = *nr;
+ struct dev_pagemap *pgmap = NULL;
+
+ do {
+ struct page *page = pfn_to_page(pfn);
+
+ pgmap = get_dev_pagemap(pfn, pgmap);
+ if (unlikely(!pgmap)) {
+ undo_dev_pagemap(nr, nr_start, pages);
+ return 0;
+ }
+ SetPageReferenced(page);
+ pages[*nr] = page;
+ get_page(page);
+ put_dev_pagemap(pgmap);
+ (*nr)++;
+ pfn++;
+ } while (addr += PAGE_SIZE, addr != end);
+ return 1;
+}
+
+static int __gup_device_huge_pmd(pmd_t pmd, unsigned long addr,
+ unsigned long end, struct page **pages, int *nr)
+{
+ unsigned long fault_pfn;
+
+ fault_pfn = pmd_pfn(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+ return __gup_device_huge(fault_pfn, addr, end, pages, nr);
+}
+
+static int __gup_device_huge_pud(pud_t pud, unsigned long addr,
+ unsigned long end, struct page **pages, int *nr)
+{
+ unsigned long fault_pfn;
+
+ fault_pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
+ return __gup_device_huge(fault_pfn, addr, end, pages, nr);
+}
+#else
+static int __gup_device_huge_pmd(pmd_t pmd, unsigned long addr,
+ unsigned long end, struct page **pages, int *nr)
+{
+ BUILD_BUG();
+ return 0;
+}
+
+static int __gup_device_huge_pud(pud_t pud, unsigned long addr,
+ unsigned long end, struct page **pages, int *nr)
+{
+ BUILD_BUG();
+ return 0;
+}
+#endif
+
static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
@@ -1278,6 +1354,9 @@ static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
if (!pmd_access_permitted(orig, write))
return 0;

+ if (pmd_devmap(orig))
+ return __gup_device_huge_pmd(orig, addr, end, pages, nr);
+
refs = 0;
head = pmd_page(orig);
page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
@@ -1314,6 +1393,9 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr,
if (!pud_access_permitted(orig, write))
return 0;

+ if (pud_devmap(orig))
+ return __gup_device_huge_pud(orig, addr, end, pages, nr);
+
refs = 0;
head = pud_page(orig);
page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
@@ -1351,6 +1433,7 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
if (!pgd_access_permitted(orig, write))
return 0;

+ BUILD_BUG_ON(pgd_devmap(orig));
refs = 0;
head = pgd_page(orig);
page = head + ((addr & ~PGDIR_MASK) >> PAGE_SHIFT);
\
 
 \ /
  Last update: 2017-03-18 10:54    [W:0.165 / U:0.096 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site