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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-03 17:12:13 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-03 17:12:13 -0700 |
commit | 7f0ef0267e20d62d45d527911a993b1e998f4968 (patch) | |
tree | de51abc7da5903f59d83e23937f22420164c9477 /fs/proc/task_mmu.c | |
parent | 862f0012549110d6f2586bf54b52ed4540cbff3a (diff) | |
parent | 9307c29524502c21f0e8a6d96d850b2f5bc0bd9a (diff) | |
download | op-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.c | 145 |
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 */ |