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https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
pagemap: switch to the new format and do some cleanup
This patch removes page-shift bits (scheduled to remove since 3.11) and completes migration to the new bit layout. Also it cleans messy macro. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mark Williamson <mwilliamson@undo-software.com> Tested-by: Mark Williamson <mwilliamson@undo-software.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a06db751c3
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deb945441b
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@ -712,23 +712,6 @@ const struct file_operations proc_tid_smaps_operations = {
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.release = proc_map_release,
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};
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/*
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* We do not want to have constant page-shift bits sitting in
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* pagemap entries and are about to reuse them some time soon.
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*
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* Here's the "migration strategy":
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* 1. when the system boots these bits remain what they are,
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* but a warning about future change is printed in log;
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* 2. once anyone clears soft-dirty bits via clear_refs file,
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* these flag is set to denote, that user is aware of the
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* new API and those page-shift bits change their meaning.
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* The respective warning is printed in dmesg;
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* 3. In a couple of releases we will remove all the mentions
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* of page-shift in pagemap entries.
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*/
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static bool soft_dirty_cleared __read_mostly;
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enum clear_refs_types {
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CLEAR_REFS_ALL = 1,
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CLEAR_REFS_ANON,
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@ -889,13 +872,6 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
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if (type < CLEAR_REFS_ALL || type >= CLEAR_REFS_LAST)
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return -EINVAL;
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if (type == CLEAR_REFS_SOFT_DIRTY) {
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soft_dirty_cleared = true;
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pr_warn_once("The pagemap bits 55-60 has changed their meaning!"
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" See the linux/Documentation/vm/pagemap.txt for "
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"details.\n");
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}
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task = get_proc_task(file_inode(file));
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if (!task)
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return -ESRCH;
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@ -963,36 +939,24 @@ typedef struct {
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struct pagemapread {
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int pos, len; /* units: PM_ENTRY_BYTES, not bytes */
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pagemap_entry_t *buffer;
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bool v2;
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};
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#define PAGEMAP_WALK_SIZE (PMD_SIZE)
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#define PAGEMAP_WALK_MASK (PMD_MASK)
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#define PM_ENTRY_BYTES sizeof(pagemap_entry_t)
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#define PM_STATUS_BITS 3
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#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS)
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#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
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#define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
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#define PM_PSHIFT_BITS 6
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#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
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#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
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#define __PM_PSHIFT(x) (((u64) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
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#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1)
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#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
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/* in "new" pagemap pshift bits are occupied with more status bits */
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#define PM_STATUS2(v2, x) (__PM_PSHIFT(v2 ? x : PAGE_SHIFT))
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#define PM_ENTRY_BYTES sizeof(pagemap_entry_t)
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#define PM_PFRAME_BITS 55
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#define PM_PFRAME_MASK GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
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#define PM_SOFT_DIRTY BIT_ULL(55)
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#define PM_FILE BIT_ULL(61)
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#define PM_SWAP BIT_ULL(62)
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#define PM_PRESENT BIT_ULL(63)
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#define __PM_SOFT_DIRTY (1LL)
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#define PM_PRESENT PM_STATUS(4LL)
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#define PM_SWAP PM_STATUS(2LL)
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#define PM_FILE PM_STATUS(1LL)
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#define PM_NOT_PRESENT(v2) PM_STATUS2(v2, 0)
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#define PM_END_OF_BUFFER 1
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static inline pagemap_entry_t make_pme(u64 val)
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static inline pagemap_entry_t make_pme(u64 frame, u64 flags)
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{
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return (pagemap_entry_t) { .pme = val };
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return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags };
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}
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static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,
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@ -1013,7 +977,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
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while (addr < end) {
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struct vm_area_struct *vma = find_vma(walk->mm, addr);
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pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
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pagemap_entry_t pme = make_pme(0, 0);
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/* End of address space hole, which we mark as non-present. */
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unsigned long hole_end;
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@ -1033,7 +997,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
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/* Addresses in the VMA. */
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if (vma->vm_flags & VM_SOFTDIRTY)
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pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY);
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pme = make_pme(0, PM_SOFT_DIRTY);
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for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
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err = add_to_pagemap(addr, &pme, pm);
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if (err)
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@ -1044,63 +1008,61 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end,
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return err;
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}
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static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
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static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm,
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struct vm_area_struct *vma, unsigned long addr, pte_t pte)
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{
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u64 frame, flags;
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u64 frame = 0, flags = 0;
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struct page *page = NULL;
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int flags2 = 0;
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if (pte_present(pte)) {
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frame = pte_pfn(pte);
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flags = PM_PRESENT;
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flags |= PM_PRESENT;
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page = vm_normal_page(vma, addr, pte);
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if (pte_soft_dirty(pte))
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flags2 |= __PM_SOFT_DIRTY;
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flags |= PM_SOFT_DIRTY;
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} else if (is_swap_pte(pte)) {
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swp_entry_t entry;
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if (pte_swp_soft_dirty(pte))
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flags2 |= __PM_SOFT_DIRTY;
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flags |= PM_SOFT_DIRTY;
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entry = pte_to_swp_entry(pte);
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frame = swp_type(entry) |
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(swp_offset(entry) << MAX_SWAPFILES_SHIFT);
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flags = PM_SWAP;
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flags |= PM_SWAP;
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if (is_migration_entry(entry))
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page = migration_entry_to_page(entry);
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} else {
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if (vma->vm_flags & VM_SOFTDIRTY)
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flags2 |= __PM_SOFT_DIRTY;
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*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, flags2));
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return;
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}
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if (page && !PageAnon(page))
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flags |= PM_FILE;
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if ((vma->vm_flags & VM_SOFTDIRTY))
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flags2 |= __PM_SOFT_DIRTY;
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if (vma->vm_flags & VM_SOFTDIRTY)
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flags |= PM_SOFT_DIRTY;
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*pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags);
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return make_pme(frame, flags);
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}
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
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pmd_t pmd, int offset, int pmd_flags2)
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static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
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pmd_t pmd, int offset, u64 flags)
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{
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u64 frame = 0;
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/*
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* Currently pmd for thp is always present because thp can not be
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* swapped-out, migrated, or HWPOISONed (split in such cases instead.)
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* This if-check is just to prepare for future implementation.
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*/
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if (pmd_present(pmd))
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*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)
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| PM_STATUS2(pm->v2, pmd_flags2) | PM_PRESENT);
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else
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*pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, pmd_flags2));
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if (pmd_present(pmd)) {
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frame = pmd_pfn(pmd) + offset;
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flags |= PM_PRESENT;
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}
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return make_pme(frame, flags);
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}
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#else
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static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
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pmd_t pmd, int offset, int pmd_flags2)
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static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm,
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pmd_t pmd, int offset, u64 flags)
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{
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return make_pme(0, 0);
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}
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#endif
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@ -1114,12 +1076,10 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
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int err = 0;
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if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
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int pmd_flags2;
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u64 flags = 0;
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if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
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pmd_flags2 = __PM_SOFT_DIRTY;
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else
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pmd_flags2 = 0;
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flags |= PM_SOFT_DIRTY;
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for (; addr != end; addr += PAGE_SIZE) {
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unsigned long offset;
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offset = (addr & ~PAGEMAP_WALK_MASK) >>
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PAGE_SHIFT;
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thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2);
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pme = thp_pmd_to_pagemap_entry(pm, *pmd, offset, flags);
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err = add_to_pagemap(addr, &pme, pm);
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if (err)
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break;
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for (; addr < end; pte++, addr += PAGE_SIZE) {
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pagemap_entry_t pme;
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pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
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pme = pte_to_pagemap_entry(pm, vma, addr, *pte);
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err = add_to_pagemap(addr, &pme, pm);
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if (err)
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break;
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}
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#ifdef CONFIG_HUGETLB_PAGE
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static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm,
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pte_t pte, int offset, int flags2)
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static pagemap_entry_t huge_pte_to_pagemap_entry(struct pagemapread *pm,
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pte_t pte, int offset, u64 flags)
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{
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if (pte_present(pte))
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*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset) |
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PM_STATUS2(pm->v2, flags2) |
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PM_PRESENT);
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else
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*pme = make_pme(PM_NOT_PRESENT(pm->v2) |
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PM_STATUS2(pm->v2, flags2));
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u64 frame = 0;
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if (pte_present(pte)) {
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frame = pte_pfn(pte) + offset;
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flags |= PM_PRESENT;
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}
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return make_pme(frame, flags);
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}
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/* This function walks within one hugetlb entry in the single call */
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struct pagemapread *pm = walk->private;
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struct vm_area_struct *vma = walk->vma;
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int err = 0;
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int flags2;
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u64 flags = 0;
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pagemap_entry_t pme;
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if (vma->vm_flags & VM_SOFTDIRTY)
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flags2 = __PM_SOFT_DIRTY;
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else
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flags2 = 0;
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flags |= PM_SOFT_DIRTY;
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for (; addr != end; addr += PAGE_SIZE) {
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int offset = (addr & ~hmask) >> PAGE_SHIFT;
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huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2);
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pme = huge_pte_to_pagemap_entry(pm, *pte, offset, flags);
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err = add_to_pagemap(addr, &pme, pm);
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if (err)
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return err;
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@ -1211,7 +1170,8 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
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* Bits 0-54 page frame number (PFN) if present
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* Bits 0-4 swap type if swapped
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* Bits 5-54 swap offset if swapped
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* Bits 55-60 page shift (page size = 1<<page shift)
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* Bit 55 pte is soft-dirty (see Documentation/vm/soft-dirty.txt)
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* Bits 56-60 zero
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* Bit 61 page is file-page or shared-anon
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* Bit 62 page swapped
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* Bit 63 page present
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if (!count)
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goto out_mm;
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pm.v2 = soft_dirty_cleared;
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pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT);
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pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY);
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ret = -ENOMEM;
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/* do not disclose physical addresses: attack vector */
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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pr_warn_once("Bits 55-60 of /proc/PID/pagemap entries are about "
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"to stop being page-shift some time soon. See the "
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"linux/Documentation/vm/pagemap.txt for details.\n");
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mm = proc_mem_open(inode, PTRACE_MODE_READ);
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if (IS_ERR(mm))
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@ -57,23 +57,14 @@
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* pagemap kernel ABI bits
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*/
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#define PM_ENTRY_BYTES sizeof(uint64_t)
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#define PM_STATUS_BITS 3
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#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS)
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#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET)
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#define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK)
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#define PM_PSHIFT_BITS 6
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#define PM_PSHIFT_OFFSET (PM_STATUS_OFFSET - PM_PSHIFT_BITS)
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#define PM_PSHIFT_MASK (((1LL << PM_PSHIFT_BITS) - 1) << PM_PSHIFT_OFFSET)
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#define __PM_PSHIFT(x) (((uint64_t) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK)
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#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1)
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#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
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#define __PM_SOFT_DIRTY (1LL)
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#define PM_PRESENT PM_STATUS(4LL)
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#define PM_SWAP PM_STATUS(2LL)
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#define PM_SOFT_DIRTY __PM_PSHIFT(__PM_SOFT_DIRTY)
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#define PM_ENTRY_BYTES 8
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#define PM_PFRAME_BITS 55
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#define PM_PFRAME_MASK ((1LL << PM_PFRAME_BITS) - 1)
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#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK)
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#define PM_SOFT_DIRTY (1ULL << 55)
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#define PM_FILE (1ULL << 61)
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#define PM_SWAP (1ULL << 62)
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#define PM_PRESENT (1ULL << 63)
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/*
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* kernel page flags
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