![Hugh Dickins](/assets/img/avatar_default.png)
KSM will need to identify its kernel merged pages unambiguously, and /proc/kpageflags will probably like to do so too. Since KSM will only be substituting anonymous pages, statistics are best preserved by making a PageKsm page a special PageAnon page: one with no anon_vma. But KSM then needs its own page_add_ksm_rmap() - keep it in ksm.h near PageKsm; and do_wp_page() must COW them, unlike singly mapped PageAnons. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Chris Wright <chrisw@redhat.com> Signed-off-by: Izik Eidus <ieidus@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Avi Kivity <avi@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
245 lines
5.6 KiB
C
245 lines
5.6 KiB
C
#include <linux/bootmem.h>
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#include <linux/compiler.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/ksm.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/hugetlb.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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#define KPMSIZE sizeof(u64)
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#define KPMMASK (KPMSIZE - 1)
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/* /proc/kpagecount - an array exposing page counts
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*
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* Each entry is a u64 representing the corresponding
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* physical page count.
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*/
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static ssize_t kpagecount_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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u64 __user *out = (u64 __user *)buf;
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struct page *ppage;
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unsigned long src = *ppos;
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unsigned long pfn;
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ssize_t ret = 0;
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u64 pcount;
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pfn = src / KPMSIZE;
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count = min_t(size_t, count, (max_pfn * KPMSIZE) - src);
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if (src & KPMMASK || count & KPMMASK)
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return -EINVAL;
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while (count > 0) {
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if (pfn_valid(pfn))
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ppage = pfn_to_page(pfn);
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else
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ppage = NULL;
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if (!ppage)
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pcount = 0;
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else
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pcount = page_mapcount(ppage);
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if (put_user(pcount, out)) {
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ret = -EFAULT;
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break;
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}
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pfn++;
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out++;
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count -= KPMSIZE;
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}
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*ppos += (char __user *)out - buf;
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if (!ret)
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ret = (char __user *)out - buf;
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return ret;
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}
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static const struct file_operations proc_kpagecount_operations = {
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.llseek = mem_lseek,
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.read = kpagecount_read,
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};
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/* /proc/kpageflags - an array exposing page flags
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*
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* Each entry is a u64 representing the corresponding
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* physical page flags.
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*/
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/* These macros are used to decouple internal flags from exported ones */
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#define KPF_LOCKED 0
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#define KPF_ERROR 1
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#define KPF_REFERENCED 2
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#define KPF_UPTODATE 3
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#define KPF_DIRTY 4
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#define KPF_LRU 5
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#define KPF_ACTIVE 6
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#define KPF_SLAB 7
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#define KPF_WRITEBACK 8
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#define KPF_RECLAIM 9
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#define KPF_BUDDY 10
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/* 11-20: new additions in 2.6.31 */
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#define KPF_MMAP 11
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#define KPF_ANON 12
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#define KPF_SWAPCACHE 13
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#define KPF_SWAPBACKED 14
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#define KPF_COMPOUND_HEAD 15
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#define KPF_COMPOUND_TAIL 16
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#define KPF_HUGE 17
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#define KPF_UNEVICTABLE 18
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#define KPF_NOPAGE 20
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#define KPF_KSM 21
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/* kernel hacking assistances
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* WARNING: subject to change, never rely on them!
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*/
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#define KPF_RESERVED 32
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#define KPF_MLOCKED 33
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#define KPF_MAPPEDTODISK 34
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#define KPF_PRIVATE 35
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#define KPF_PRIVATE_2 36
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#define KPF_OWNER_PRIVATE 37
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#define KPF_ARCH 38
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#define KPF_UNCACHED 39
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static inline u64 kpf_copy_bit(u64 kflags, int ubit, int kbit)
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{
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return ((kflags >> kbit) & 1) << ubit;
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}
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static u64 get_uflags(struct page *page)
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{
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u64 k;
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u64 u;
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/*
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* pseudo flag: KPF_NOPAGE
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* it differentiates a memory hole from a page with no flags
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*/
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if (!page)
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return 1 << KPF_NOPAGE;
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k = page->flags;
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u = 0;
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/*
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* pseudo flags for the well known (anonymous) memory mapped pages
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*
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* Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
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* simple test in page_mapped() is not enough.
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*/
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if (!PageSlab(page) && page_mapped(page))
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u |= 1 << KPF_MMAP;
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if (PageAnon(page))
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u |= 1 << KPF_ANON;
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if (PageKsm(page))
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u |= 1 << KPF_KSM;
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/*
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* compound pages: export both head/tail info
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* they together define a compound page's start/end pos and order
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*/
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if (PageHead(page))
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u |= 1 << KPF_COMPOUND_HEAD;
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if (PageTail(page))
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u |= 1 << KPF_COMPOUND_TAIL;
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if (PageHuge(page))
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u |= 1 << KPF_HUGE;
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u |= kpf_copy_bit(k, KPF_LOCKED, PG_locked);
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/*
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* Caveats on high order pages:
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* PG_buddy will only be set on the head page; SLUB/SLQB do the same
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* for PG_slab; SLOB won't set PG_slab at all on compound pages.
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*/
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u |= kpf_copy_bit(k, KPF_SLAB, PG_slab);
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u |= kpf_copy_bit(k, KPF_BUDDY, PG_buddy);
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u |= kpf_copy_bit(k, KPF_ERROR, PG_error);
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u |= kpf_copy_bit(k, KPF_DIRTY, PG_dirty);
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u |= kpf_copy_bit(k, KPF_UPTODATE, PG_uptodate);
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u |= kpf_copy_bit(k, KPF_WRITEBACK, PG_writeback);
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u |= kpf_copy_bit(k, KPF_LRU, PG_lru);
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u |= kpf_copy_bit(k, KPF_REFERENCED, PG_referenced);
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u |= kpf_copy_bit(k, KPF_ACTIVE, PG_active);
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u |= kpf_copy_bit(k, KPF_RECLAIM, PG_reclaim);
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u |= kpf_copy_bit(k, KPF_SWAPCACHE, PG_swapcache);
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u |= kpf_copy_bit(k, KPF_SWAPBACKED, PG_swapbacked);
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u |= kpf_copy_bit(k, KPF_UNEVICTABLE, PG_unevictable);
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u |= kpf_copy_bit(k, KPF_MLOCKED, PG_mlocked);
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#ifdef CONFIG_IA64_UNCACHED_ALLOCATOR
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u |= kpf_copy_bit(k, KPF_UNCACHED, PG_uncached);
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#endif
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u |= kpf_copy_bit(k, KPF_RESERVED, PG_reserved);
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u |= kpf_copy_bit(k, KPF_MAPPEDTODISK, PG_mappedtodisk);
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u |= kpf_copy_bit(k, KPF_PRIVATE, PG_private);
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u |= kpf_copy_bit(k, KPF_PRIVATE_2, PG_private_2);
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u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE, PG_owner_priv_1);
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u |= kpf_copy_bit(k, KPF_ARCH, PG_arch_1);
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return u;
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};
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static ssize_t kpageflags_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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u64 __user *out = (u64 __user *)buf;
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struct page *ppage;
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unsigned long src = *ppos;
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unsigned long pfn;
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ssize_t ret = 0;
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pfn = src / KPMSIZE;
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count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
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if (src & KPMMASK || count & KPMMASK)
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return -EINVAL;
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while (count > 0) {
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if (pfn_valid(pfn))
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ppage = pfn_to_page(pfn);
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else
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ppage = NULL;
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if (put_user(get_uflags(ppage), out)) {
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ret = -EFAULT;
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break;
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}
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pfn++;
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out++;
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count -= KPMSIZE;
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}
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*ppos += (char __user *)out - buf;
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if (!ret)
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ret = (char __user *)out - buf;
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return ret;
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}
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static const struct file_operations proc_kpageflags_operations = {
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.llseek = mem_lseek,
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.read = kpageflags_read,
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};
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static int __init proc_page_init(void)
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{
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proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
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proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
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return 0;
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}
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module_init(proc_page_init);
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