Re: [PATCH v3 4/4] pagemap: switch to the new format and do some cleanup
From: Mark Williamson <hidden>
Date: 2015-06-12 18:49:53
Also in:
linux-mm, lkml
One tiny nitpick / typo, inline below - functionally, this looks good from our side... Reviewed-by: mwilliamson-/4lU09Eg6ahx67MzidHQgQC/G2K4zDHf@public.gmane.org Tested-by: mwilliamson-/4lU09Eg6ahx67MzidHQgQC/G2K4zDHf@public.gmane.org On Tue, Jun 9, 2015 at 9:00 PM, Konstantin Khlebnikov [off-list ref] wrote:
From: Konstantin Khlebnikov <redacted>
<...snip...>
-#define __PM_SOFT_DIRTY (1LL) -#define __PM_MMAP_EXCLUSIVE (2LL) -#define PM_PRESENT PM_STATUS(4LL) -#define PM_SWAP PM_STATUS(2LL) -#define PM_FILE PM_STATUS(1LL) -#define PM_NOT_PRESENT(v2) PM_STATUS2(v2, 0) +#define PM_ENTRY_BYTES sizeof(pagemap_entry_t) +#define PM_PFEAME_BITS 54 +#define PM_PFRAME_MASK GENMASK_ULL(PM_PFEAME_BITS - 1, 0)
s/PM_FEAME_BITS/PM_FRAME_BITS/ I presume?
quoted hunk ↗ jump to hunk
+#define PM_SOFT_DIRTY BIT_ULL(55) +#define PM_MMAP_EXCLUSIVE BIT_ULL(56) +#define PM_FILE BIT_ULL(61) +#define PM_SWAP BIT_ULL(62) +#define PM_PRESENT BIT_ULL(63) + #define PM_END_OF_BUFFER 1 -static inline pagemap_entry_t make_pme(u64 val) +static inline pagemap_entry_t make_pme(u64 frame, u64 flags) { - return (pagemap_entry_t) { .pme = val }; + return (pagemap_entry_t) { .pme = (frame & PM_PFRAME_MASK) | flags }; } static int add_to_pagemap(unsigned long addr, pagemap_entry_t *pme,@@ -1013,7 +977,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end, while (addr < end) { struct vm_area_struct *vma = find_vma(walk->mm, addr); - pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2)); + pagemap_entry_t pme = make_pme(0, 0); /* End of address space hole, which we mark as non-present. */ unsigned long hole_end;@@ -1033,7 +997,7 @@ static int pagemap_pte_hole(unsigned long start, unsigned long end, /* Addresses in the VMA. */ if (vma->vm_flags & VM_SOFTDIRTY) - pme.pme |= PM_STATUS2(pm->v2, __PM_SOFT_DIRTY); + pme = make_pme(0, PM_SOFT_DIRTY); for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) { err = add_to_pagemap(addr, &pme, pm); if (err)@@ -1044,50 +1008,44 @@ out: return err; } -static void pte_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm, +static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, struct vm_area_struct *vma, unsigned long addr, pte_t pte) { - u64 frame = 0, flags; + u64 frame = 0, flags = 0; struct page *page = NULL; - int flags2 = 0; if (pte_present(pte)) { if (pm->show_pfn) frame = pte_pfn(pte); - flags = PM_PRESENT; + flags |= PM_PRESENT; page = vm_normal_page(vma, addr, pte); if (pte_soft_dirty(pte)) - flags2 |= __PM_SOFT_DIRTY; + flags |= PM_SOFT_DIRTY; } else if (is_swap_pte(pte)) { swp_entry_t entry; if (pte_swp_soft_dirty(pte)) - flags2 |= __PM_SOFT_DIRTY; + flags |= PM_SOFT_DIRTY; entry = pte_to_swp_entry(pte); frame = swp_type(entry) | (swp_offset(entry) << MAX_SWAPFILES_SHIFT); - flags = PM_SWAP; + flags |= PM_SWAP; if (is_migration_entry(entry)) page = migration_entry_to_page(entry); - } else { - if (vma->vm_flags & VM_SOFTDIRTY) - flags2 |= __PM_SOFT_DIRTY; - *pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, flags2)); - return; } if (page && !PageAnon(page)) flags |= PM_FILE; if (page && page_mapcount(page) == 1) - flags2 |= __PM_MMAP_EXCLUSIVE; - if ((vma->vm_flags & VM_SOFTDIRTY)) - flags2 |= __PM_SOFT_DIRTY; + flags |= PM_MMAP_EXCLUSIVE; + if (vma->vm_flags & VM_SOFTDIRTY) + flags |= PM_SOFT_DIRTY; - *pme = make_pme(PM_PFRAME(frame) | PM_STATUS2(pm->v2, flags2) | flags); + return make_pme(frame, flags); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE -static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm, - pmd_t pmd, int offset, int pmd_flags2) +static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm, + pmd_t pmd, int offset, u64 flags) { u64 frame = 0;@@ -1099,15 +1057,16 @@ static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *p if (pmd_present(pmd)) { if (pm->show_pfn) frame = pmd_pfn(pmd) + offset; - *pme = make_pme(PM_PFRAME(frame) | PM_PRESENT | - PM_STATUS2(pm->v2, pmd_flags2)); - } else - *pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, pmd_flags2)); + flags |= PM_PRESENT; + } + + return make_pme(frame, flags); } #else -static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemapread *pm, - pmd_t pmd, int offset, int pmd_flags2) +static pagemap_entry_t thp_pmd_to_pagemap_entry(struct pagemapread *pm, + pmd_t pmd, int offset, u64 flags) { + return make_pme(0, 0); } #endif@@ -1121,18 +1080,16 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, int err = 0; if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { - int pmd_flags2; + u64 flags = 0; if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd)) - pmd_flags2 = __PM_SOFT_DIRTY; - else - pmd_flags2 = 0; + flags |= PM_SOFT_DIRTY; if (pmd_present(*pmd)) { struct page *page = pmd_page(*pmd); if (page_mapcount(page) == 1) - pmd_flags2 |= __PM_MMAP_EXCLUSIVE; + flags |= PM_MMAP_EXCLUSIVE; } for (; addr != end; addr += PAGE_SIZE) {@@ -1141,7 +1098,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, offset = (addr & ~PAGEMAP_WALK_MASK) >> PAGE_SHIFT; - thp_pmd_to_pagemap_entry(&pme, pm, *pmd, offset, pmd_flags2); + pme = thp_pmd_to_pagemap_entry(pm, *pmd, offset, flags); err = add_to_pagemap(addr, &pme, pm); if (err) break;@@ -1161,7 +1118,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, for (; addr < end; pte++, addr += PAGE_SIZE) { pagemap_entry_t pme; - pte_to_pagemap_entry(&pme, pm, vma, addr, *pte); + pme = pte_to_pagemap_entry(pm, vma, addr, *pte); err = add_to_pagemap(addr, &pme, pm); if (err) break;@@ -1174,19 +1131,18 @@ 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, struct pagemapread *pm, - pte_t pte, int offset, int flags2) +static pagemap_entry_t huge_pte_to_pagemap_entry(struct pagemapread *pm, + pte_t pte, int offset, u64 flags) { u64 frame = 0; if (pte_present(pte)) { if (pm->show_pfn) frame = pte_pfn(pte) + offset; - *pme = make_pme(PM_PFRAME(frame) | PM_PRESENT | - PM_STATUS2(pm->v2, flags2)); - } else - *pme = make_pme(PM_NOT_PRESENT(pm->v2) | - PM_STATUS2(pm->v2, flags2)); + flags |= PM_PRESENT; + } + + return make_pme(frame, flags); } /* This function walks within one hugetlb entry in the single call */@@ -1197,17 +1153,15 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, struct pagemapread *pm = walk->private; struct vm_area_struct *vma = walk->vma; int err = 0; - int flags2; + u64 flags = 0; pagemap_entry_t pme; if (vma->vm_flags & VM_SOFTDIRTY) - flags2 = __PM_SOFT_DIRTY; - else - flags2 = 0; + flags |= PM_SOFT_DIRTY; for (; addr != end; addr += PAGE_SIZE) { int offset = (addr & ~hmask) >> PAGE_SHIFT; - huge_pte_to_pagemap_entry(&pme, pm, *pte, offset, flags2); + pme = huge_pte_to_pagemap_entry(pm, *pte, offset, flags); err = add_to_pagemap(addr, &pme, pm); if (err) return err;@@ -1228,7 +1182,9 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, * Bits 0-54 page frame number (PFN) if present * Bits 0-4 swap type if swapped * Bits 5-54 swap offset if swapped - * Bits 55-60 page shift (page size = 1<<page shift) + * Bit 55 pte is soft-dirty (see Documentation/vm/soft-dirty.txt) + * Bit 56 page exclusively mapped + * Bits 57-60 zero * Bit 61 page is file-page or shared-anon * Bit 62 page swapped * Bit 63 page present@@ -1269,7 +1225,6 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, /* do not disclose physical addresses: attack vector */ pm.show_pfn = file_ns_capable(file, &init_user_ns, CAP_SYS_ADMIN); - pm.v2 = soft_dirty_cleared; pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY); ret = -ENOMEM;@@ -1339,10 +1294,6 @@ static int pagemap_open(struct inode *inode, struct file *file) { struct mm_struct *mm; - 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"); - mm = proc_mem_open(inode, PTRACE_MODE_READ); if (IS_ERR(mm)) return PTR_ERR(mm);diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c index 3a9f193..1fa872e 100644 --- a/tools/vm/page-types.c +++ b/tools/vm/page-types.c@@ -57,26 +57,15 @@ * pagemap kernel ABI bits */ -#define PM_ENTRY_BYTES sizeof(uint64_t) -#define PM_STATUS_BITS 3 -#define PM_STATUS_OFFSET (64 - PM_STATUS_BITS) -#define PM_STATUS_MASK (((1LL << PM_STATUS_BITS) - 1) << PM_STATUS_OFFSET) -#define PM_STATUS(nr) (((nr) << PM_STATUS_OFFSET) & PM_STATUS_MASK) -#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) (((uint64_t) (x) << PM_PSHIFT_OFFSET) & PM_PSHIFT_MASK) -#define PM_PFRAME_MASK ((1LL << PM_PSHIFT_OFFSET) - 1) -#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK) - -#define __PM_SOFT_DIRTY (1LL) -#define __PM_MMAP_EXCLUSIVE (2LL) -#define PM_PRESENT PM_STATUS(4LL) -#define PM_SWAP PM_STATUS(2LL) -#define PM_FILE PM_STATUS(1LL) -#define PM_SOFT_DIRTY __PM_PSHIFT(__PM_SOFT_DIRTY) -#define PM_MMAP_EXCLUSIVE __PM_PSHIFT(__PM_MMAP_EXCLUSIVE) - +#define PM_ENTRY_BYTES 8 +#define PM_PFEAME_BITS 54 +#define PM_PFRAME_MASK ((1LL << PM_PFEAME_BITS) - 1) +#define PM_PFRAME(x) ((x) & PM_PFRAME_MASK) +#define PM_SOFT_DIRTY (1ULL << 55) +#define PM_MMAP_EXCLUSIVE (1ULL << 56) +#define PM_FILE (1ULL << 61) +#define PM_SWAP (1ULL << 62) +#define PM_PRESENT (1ULL << 63) /* * kernel page flags