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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 17:12:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 17:12:13 -0700
commit7f0ef0267e20d62d45d527911a993b1e998f4968 (patch)
treede51abc7da5903f59d83e23937f22420164c9477 /fs/proc/task_mmu.c
parent862f0012549110d6f2586bf54b52ed4540cbff3a (diff)
parent9307c29524502c21f0e8a6d96d850b2f5bc0bd9a (diff)
downloadop-kernel-dev-7f0ef0267e20d62d45d527911a993b1e998f4968.zip
op-kernel-dev-7f0ef0267e20d62d45d527911a993b1e998f4968.tar.gz
Merge branch 'akpm' (updates from Andrew Morton)
Merge first patch-bomb from Andrew Morton: - various misc bits - I'm been patchmonkeying ocfs2 for a while, as Joel and Mark have been distracted. There has been quite a bit of activity. - About half the MM queue - Some backlight bits - Various lib/ updates - checkpatch updates - zillions more little rtc patches - ptrace - signals - exec - procfs - rapidio - nbd - aoe - pps - memstick - tools/testing/selftests updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (445 commits) tools/testing/selftests: don't assume the x bit is set on scripts selftests: add .gitignore for kcmp selftests: fix clean target in kcmp Makefile selftests: add .gitignore for vm selftests: add hugetlbfstest self-test: fix make clean selftests: exit 1 on failure kernel/resource.c: remove the unneeded assignment in function __find_resource aio: fix wrong comment in aio_complete() drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode drivers/memstick/host/r592.c: convert to module_pci_driver drivers/memstick/host/jmb38x_ms: convert to module_pci_driver pps-gpio: add device-tree binding and support drivers/pps/clients/pps-gpio.c: convert to module_platform_driver drivers/pps/clients/pps-gpio.c: convert to devm_* helpers drivers/parport/share.c: use kzalloc Documentation/accounting/getdelays.c: avoid strncpy in accounting tool aoe: update internal version number to v83 aoe: update copyright date aoe: perform I/O completions in parallel ...
Diffstat (limited to 'fs/proc/task_mmu.c')
-rw-r--r--fs/proc/task_mmu.c145
1 files changed, 116 insertions, 29 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3e636d8..dbf61f6 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -11,6 +11,7 @@
#include <linux/rmap.h>
#include <linux/swap.h>
#include <linux/swapops.h>
+#include <linux/mmu_notifier.h>
#include <asm/elf.h>
#include <asm/uaccess.h>
@@ -688,10 +689,58 @@ const struct file_operations proc_tid_smaps_operations = {
.release = seq_release_private,
};
+/*
+ * We do not want to have constant page-shift bits sitting in
+ * pagemap entries and are about to reuse them some time soon.
+ *
+ * Here's the "migration strategy":
+ * 1. when the system boots these bits remain what they are,
+ * but a warning about future change is printed in log;
+ * 2. once anyone clears soft-dirty bits via clear_refs file,
+ * these flag is set to denote, that user is aware of the
+ * new API and those page-shift bits change their meaning.
+ * The respective warning is printed in dmesg;
+ * 3. In a couple of releases we will remove all the mentions
+ * of page-shift in pagemap entries.
+ */
+
+static bool soft_dirty_cleared __read_mostly;
+
+enum clear_refs_types {
+ CLEAR_REFS_ALL = 1,
+ CLEAR_REFS_ANON,
+ CLEAR_REFS_MAPPED,
+ CLEAR_REFS_SOFT_DIRTY,
+ CLEAR_REFS_LAST,
+};
+
+struct clear_refs_private {
+ struct vm_area_struct *vma;
+ enum clear_refs_types type;
+};
+
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+ unsigned long addr, pte_t *pte)
+{
+#ifdef CONFIG_MEM_SOFT_DIRTY
+ /*
+ * The soft-dirty tracker uses #PF-s to catch writes
+ * to pages, so write-protect the pte as well. See the
+ * Documentation/vm/soft-dirty.txt for full description
+ * of how soft-dirty works.
+ */
+ pte_t ptent = *pte;
+ ptent = pte_wrprotect(ptent);
+ ptent = pte_clear_flags(ptent, _PAGE_SOFT_DIRTY);
+ set_pte_at(vma->vm_mm, addr, pte, ptent);
+#endif
+}
+
static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end, struct mm_walk *walk)
{
- struct vm_area_struct *vma = walk->private;
+ struct clear_refs_private *cp = walk->private;
+ struct vm_area_struct *vma = cp->vma;
pte_t *pte, ptent;
spinlock_t *ptl;
struct page *page;
@@ -706,6 +755,11 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(ptent))
continue;
+ if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+ clear_soft_dirty(vma, addr, pte);
+ continue;
+ }
+
page = vm_normal_page(vma, addr, ptent);
if (!page)
continue;
@@ -719,10 +773,6 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
return 0;
}
-#define CLEAR_REFS_ALL 1
-#define CLEAR_REFS_ANON 2
-#define CLEAR_REFS_MAPPED 3
-
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
@@ -730,7 +780,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
char buffer[PROC_NUMBUF];
struct mm_struct *mm;
struct vm_area_struct *vma;
- int type;
+ enum clear_refs_types type;
+ int itype;
int rv;
memset(buffer, 0, sizeof(buffer));
@@ -738,23 +789,37 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
count = sizeof(buffer) - 1;
if (copy_from_user(buffer, buf, count))
return -EFAULT;
- rv = kstrtoint(strstrip(buffer), 10, &type);
+ rv = kstrtoint(strstrip(buffer), 10, &itype);
if (rv < 0)
return rv;
- if (type < CLEAR_REFS_ALL || type > CLEAR_REFS_MAPPED)
+ type = (enum clear_refs_types)itype;
+ if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
return -EINVAL;
+
+ if (type == CLEAR_REFS_SOFT_DIRTY) {
+ soft_dirty_cleared = true;
+ pr_warn_once("The pagemap bits 55-60 has changed their meaning! "
+ "See the linux/Documentation/vm/pagemap.txt for details.\n");
+ }
+
task = get_proc_task(file_inode(file));
if (!task)
return -ESRCH;
mm = get_task_mm(task);
if (mm) {
+ struct clear_refs_private cp = {
+ .type = type,
+ };
struct mm_walk clear_refs_walk = {
.pmd_entry = clear_refs_pte_range,
.mm = mm,
+ .private = &cp,
};
down_read(&mm->mmap_sem);
+ if (type == CLEAR_REFS_SOFT_DIRTY)
+ mmu_notifier_invalidate_range_start(mm, 0, -1);
for (vma = mm->mmap; vma; vma = vma->vm_next) {
- clear_refs_walk.private = vma;
+ cp.vma = vma;
if (is_vm_hugetlb_page(vma))
continue;
/*
@@ -773,6 +838,8 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
walk_page_range(vma->vm_start, vma->vm_end,
&clear_refs_walk);
}
+ if (type == CLEAR_REFS_SOFT_DIRTY)
+ mmu_notifier_invalidate_range_end(mm, 0, -1);
flush_tlb_mm(mm);
up_read(&mm->mmap_sem);
mmput(mm);
@@ -794,6 +861,7 @@ typedef struct {
struct pagemapread {
int pos, len;
pagemap_entry_t *buffer;
+ bool v2;
};
#define PAGEMAP_WALK_SIZE (PMD_SIZE)
@@ -807,14 +875,17 @@ struct pagemapread {
#define PM_PSHIFT_BITS 6
#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
-#define PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
+#define __PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1)
#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
+/* in "new" pagemap pshift bits are occupied with more status bits */
+#define PM_STATUS2(v2, x) (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
+#define __PM_SOFT_DIRTY (1LL)
#define PM_PRESENT PM_STATUS(4LL)
#define PM_SWAP PM_STATUS(2LL)
#define PM_FILE PM_STATUS(1LL)
-#define PM_NOT_PRESENT PM_PSHIFT(PAGE_SHIFT)
+#define PM_NOT_PRESENT(v2) PM_STATUS2(v2, 0)
#define PM_END_OF_BUFFER 1
static inline pagemap_entry_t make_pme(u64 val)
@@ -837,7 +908,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
struct pagemapread *pm = walk->private;
unsigned long addr;
int err = 0;
- pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);
+ pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
for (addr = start; addr < end; addr += PAGE_SIZE) {
err = add_to_pagemap(addr, &pme, pm);
@@ -847,11 +918,12 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
return err;
}
-static void pte_to_pagemap_entry(pagemap_entry_t *pme,
+static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
struct vm_area_struct *vma, unsigned long addr, pte_t pte)
{
u64 frame, flags;
struct page *page = NULL;
+ int flags2 = 0;
if (pte_present(pte)) {
frame = pte_pfn(pte);
@@ -866,19 +938,21 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme,
if (is_migration_entry(entry))
page = migration_entry_to_page(entry);
} else {
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
return;
}
if (page && !PageAnon(page))
flags |= PM_FILE;
+ if (pte_soft_dirty(pte))
+ flags2 |= __PM_SOFT_DIRTY;
- *pme = make_pme(PM_PFRAME(frame) | PM_PSHIFT(PAGE_SHIFT) | flags);
+ *pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
- pmd_t pmd, int offset)
+static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+ pmd_t pmd, int offset, int pmd_flags2)
{
/*
* Currently pmd for thp is always present because thp can not be
@@ -887,13 +961,13 @@ static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
*/
if (pmd_present(pmd))
*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
- | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ | PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
else
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
#else
-static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
- pmd_t pmd, int offset)
+static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
+ pmd_t pmd, int offset, int pmd_flags2)
{
}
#endif
@@ -905,17 +979,20 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct pagemapread *pm = walk->private;
pte_t *pte;
int err = 0;
- pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);
+ pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
/* find the first VMA at or above 'addr' */
vma = find_vma(walk->mm, addr);
if (vma && pmd_trans_huge_lock(pmd, vma) == 1) {
+ int pmd_flags2;
+
+ pmd_flags2 = (pmd_soft_dirty(*pmd) ? __PM_SOFT_DIRTY : 0);
for (; addr != end; addr += PAGE_SIZE) {
unsigned long offset;
offset = (addr & ~PAGEMAP_WALK_MASK) >>
PAGE_SHIFT;
- thp_pmd_to_pagemap_entry(&pme, *pmd, offset);
+ thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2);
err = add_to_pagemap(addr, &pme, pm);
if (err)
break;
@@ -932,7 +1009,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
* and need a new, higher one */
if (vma && (addr >= vma->vm_end)) {
vma = find_vma(walk->mm, addr);
- pme = make_pme(PM_NOT_PRESENT);
+ pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
/* check that 'vma' actually covers this address,
@@ -940,7 +1017,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
if (vma && (vma->vm_start <= addr) &&
!is_vm_hugetlb_page(vma)) {
pte = pte_offset_map(pmd, addr);
- pte_to_pagemap_entry(&pme, vma, addr, *pte);
+ pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
/* unmap before userspace copy */
pte_unmap(pte);
}
@@ -955,14 +1032,14 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
}
#ifdef CONFIG_HUGETLB_PAGE
-static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme,
+static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
pte_t pte, int offset)
{
if (pte_present(pte))
*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)
- | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);
+ | PM_STATUS2(pm->v2, 0) | PM_PRESENT);
else
- *pme = make_pme(PM_NOT_PRESENT);
+ *pme = make_pme(PM_NOT_PRESENT(pm->v2));
}
/* This function walks within one hugetlb entry in the single call */
@@ -976,7 +1053,7 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
for (; addr != end; addr += PAGE_SIZE) {
int offset = (addr & ~hmask) >> PAGE_SHIFT;
- huge_pte_to_pagemap_entry(&pme, *pte, offset);
+ huge_pte_to_pagemap_entry(&pme, pm, *pte, offset);
err = add_to_pagemap(addr, &pme, pm);
if (err)
return err;
@@ -1038,6 +1115,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
if (!count)
goto out_task;
+ pm.v2 = soft_dirty_cleared;
pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
pm.buffer = kmalloc(pm.len, GFP_TEMPORARY);
ret = -ENOMEM;
@@ -1110,9 +1188,18 @@ out:
return ret;
}
+static int pagemap_open(struct inode *inode, struct file *file)
+{
+ pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
+ "to stop being page-shift some time soon. See the "
+ "linux/Documentation/vm/pagemap.txt for details.\n");
+ return 0;
+}
+
const struct file_operations proc_pagemap_operations = {
.llseek = mem_lseek, /* borrow this */
.read = pagemap_read,
+ .open = pagemap_open,
};
#endif /* CONFIG_PROC_PAGE_MONITOR */
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