Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=304daa8132a95e998b6716d4b7bd8bd76aa152b2
Commit: 304daa8132a95e998b6716d4b7bd8bd76aa152b2
Parent: 161f47bf41c5ece90ac53cbb6a4cb9bf74ce0ef6
Author: Matt Mackall <[EMAIL PROTECTED]>
AuthorDate: Mon Feb 4 22:29:06 2008 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Feb 5 09:44:17 2008 -0800
maps4: add /proc/kpageflags interface
This makes a subset of physical page flags available to userspace. Together
with /proc/pid/kpagemap, this allows tracking of a wide variety of VM
behaviors.
Exported flags are decoupled from the kernel's internal flags. This
allows us to reorder flag bits, and synthesize any bits that get
redefined in terms of other bits.
[EMAIL PROTECTED]: remove unneeded access_ok()]
[EMAIL PROTECTED]: s/0/NULL/]
Signed-off-by: Matt Mackall <[EMAIL PROTECTED]>
Cc: Dave Hansen <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/proc/proc_misc.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 83 insertions(+), 1 deletions(-)
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index 19b69f9..fd751ea 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -699,7 +699,10 @@ static ssize_t kpagecount_read(struct file *file, char
__user *buf,
return -EIO;
while (count > 0) {
- ppage = pfn_to_page(pfn++);
+ ppage = NULL;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
if (!ppage)
pcount = 0;
else
@@ -724,6 +727,84 @@ static struct file_operations proc_kpagecount_operations =
{
.read = kpagecount_read,
};
+/* /proc/kpageflags - an array exposing page flags
+ *
+ * Each entry is a u64 representing the corresponding
+ * physical page flags.
+ */
+
+/* These macros are used to decouple internal flags from exported ones */
+
+#define KPF_LOCKED 0
+#define KPF_ERROR 1
+#define KPF_REFERENCED 2
+#define KPF_UPTODATE 3
+#define KPF_DIRTY 4
+#define KPF_LRU 5
+#define KPF_ACTIVE 6
+#define KPF_SLAB 7
+#define KPF_WRITEBACK 8
+#define KPF_RECLAIM 9
+#define KPF_BUDDY 10
+
+#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)
+
+static ssize_t kpageflags_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 __user *out = (u64 __user *)buf;
+ struct page *ppage;
+ unsigned long src = *ppos;
+ unsigned long pfn;
+ ssize_t ret = 0;
+ u64 kflags, uflags;
+
+ pfn = src / KPMSIZE;
+ count = min_t(unsigned long, count, (max_pfn * KPMSIZE) - src);
+ if (src & KPMMASK || count & KPMMASK)
+ return -EIO;
+
+ while (count > 0) {
+ ppage = NULL;
+ if (pfn_valid(pfn))
+ ppage = pfn_to_page(pfn);
+ pfn++;
+ if (!ppage)
+ kflags = 0;
+ else
+ kflags = ppage->flags;
+
+ uflags = kpf_copy_bit(KPF_LOCKED, PG_locked, kflags) |
+ kpf_copy_bit(kflags, KPF_ERROR, PG_error) |
+ kpf_copy_bit(kflags, KPF_REFERENCED, PG_referenced) |
+ kpf_copy_bit(kflags, KPF_UPTODATE, PG_uptodate) |
+ kpf_copy_bit(kflags, KPF_DIRTY, PG_dirty) |
+ kpf_copy_bit(kflags, KPF_LRU, PG_lru) |
+ kpf_copy_bit(kflags, KPF_ACTIVE, PG_active) |
+ kpf_copy_bit(kflags, KPF_SLAB, PG_slab) |
+ kpf_copy_bit(kflags, KPF_WRITEBACK, PG_writeback) |
+ kpf_copy_bit(kflags, KPF_RECLAIM, PG_reclaim) |
+ kpf_copy_bit(kflags, KPF_BUDDY, PG_buddy);
+
+ if (put_user(uflags, out++)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ count -= KPMSIZE;
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static struct file_operations proc_kpageflags_operations = {
+ .llseek = mem_lseek,
+ .read = kpageflags_read,
+};
+
struct proc_dir_entry *proc_root_kcore;
void create_seq_entry(char *name, mode_t mode, const struct file_operations *f)
@@ -805,6 +886,7 @@ void __init proc_misc_init(void)
}
#endif
create_seq_entry("kpagecount", S_IRUSR, &proc_kpagecount_operations);
+ create_seq_entry("kpageflags", S_IRUSR, &proc_kpageflags_operations);
#ifdef CONFIG_PROC_VMCORE
proc_vmcore = create_proc_entry("vmcore", S_IRUSR, NULL);
if (proc_vmcore)
-
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