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Subject[PATCH] page-types: decode flags directly from command line
Teach page-types to decode page flags directly from the command
line.

Why is this useful? For instance, if you're using memory hotplug
and see this in /var/log/messages:

kernel: removing from LRU failed 3836dd0/1/1e00000000000400

It would be nice to decode those page flags without staring at
the source.

Example usage and output:

linux-2.6/Documentation/vm$ ./page-types -d 0x1e00000000000400
flags page-count MB symbolic-flags long-symbolic-flags
0x1e00000000000400 1 0 __________B_______________________buddy
total 1 0

Signed-off-by: Alex Chiang <achiang@hp.com>
---
page-types.c | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
---
diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c
index 3ec4f2a..a55c624 100644
--- a/Documentation/vm/page-types.c
+++ b/Documentation/vm/page-types.c
@@ -674,6 +674,7 @@ static void usage(void)
printf(
"page-types [options]\n"
" -r|--raw Raw mode, for kernel developers\n"
+" -d|--decode flags Decode a single page's flags\n"
" -a|--addr addr-spec Walk a range of pages\n"
" -b|--bits bits-spec Walk pages with specified bits\n"
" -p|--pid pid Walk process address space\n"
@@ -682,10 +683,12 @@ static void usage(void)
#endif
" -l|--list Show page details in ranges\n"
" -L|--list-each Show page details one by one\n"
-" -N|--no-summary Don't show summay info\n"
+" -N|--no-summary Don't show summary info\n"
" -X|--hwpoison hwpoison pages\n"
" -x|--unpoison unpoison pages\n"
" -h|--help Show this usage message\n"
+"flags:\n"
+" 0x0000000000000400 A single page's flags, e.g.\n"
"addr-spec:\n"
" N one page at offset N (unit: pages)\n"
" N+M pages range from N to N+M-1\n"
@@ -884,12 +887,28 @@ static void parse_bits_mask(const char *optarg)
add_bits_filter(mask, bits);
}

+static void decode_flags_and_exit(const char *optarg)
+{
+ uint64_t flags;
+
+ flags = parse_number(optarg);
+
+ opt_list = 0;
+ opt_hwpoison = 0;
+ opt_unpoison = 0;
+
+ add_page(0, 0, flags);
+ show_summary();
+
+ exit(0);
+}

static struct option opts[] = {
{ "raw" , 0, NULL, 'r' },
{ "pid" , 1, NULL, 'p' },
{ "file" , 1, NULL, 'f' },
{ "addr" , 1, NULL, 'a' },
+ { "decode" , 1, NULL, 'd' },
{ "bits" , 1, NULL, 'b' },
{ "list" , 0, NULL, 'l' },
{ "list-each" , 0, NULL, 'L' },
@@ -907,7 +926,7 @@ int main(int argc, char *argv[])
page_size = getpagesize();

while ((c = getopt_long(argc, argv,
- "rp:f:a:b:lLNXxh", opts, NULL)) != -1) {
+ "rp:f:a:b:d:lLNXxh", opts, NULL)) != -1) {
switch (c) {
case 'r':
opt_raw = 1;
@@ -924,6 +943,9 @@ int main(int argc, char *argv[])
case 'b':
parse_bits_mask(optarg);
break;
+ case 'd':
+ decode_flags_and_exit(optarg);
+ break;
case 'l':
opt_list = 1;
break;

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