page-types: learn to describe flags directly from command line
Teach page-types to describe 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 3836dd0/1/1e00000000000010
It would be nice to decode those page flags without staring at the source.
Example usage and output:
# Documentation/vm/page-types -d 0x10
0x0000000000000010 ____D_____________________________ dirty
# Documentation/vm/page-types -d anon
0x0000000000001000 ____________a_____________________ anonymous
# Documentation/vm/page-types -d anon,0x10
0x0000000000001010 ____D_______a_____________________ dirty,anonymous
[achiang@hp.com: documentation]
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Haicheng Li <haicheng.li@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c
index 2279b61..8c28be6 100644
--- a/Documentation/vm/page-types.c
+++ b/Documentation/vm/page-types.c
@@ -674,6 +674,7 @@
printf(
"page-types [options]\n"
" -r|--raw Raw mode, for kernel developers\n"
+" -d|--describe flags Describe 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"
@@ -686,6 +687,10 @@
" -X|--hwpoison hwpoison pages\n"
" -x|--unpoison unpoison pages\n"
" -h|--help Show this usage message\n"
+"flags:\n"
+" 0x10 bitfield format, e.g.\n"
+" anon bit-name, e.g.\n"
+" 0x10,anon comma-separated list, 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"
@@ -884,6 +889,15 @@
add_bits_filter(mask, bits);
}
+static void describe_flags(const char *optarg)
+{
+ uint64_t flags = parse_flag_names(optarg, 0);
+
+ printf("0x%016llx\t%s\t%s\n",
+ (unsigned long long)flags,
+ page_flag_name(flags),
+ page_flag_longname(flags));
+}
static const struct option opts[] = {
{ "raw" , 0, NULL, 'r' },
@@ -891,6 +905,7 @@
{ "file" , 1, NULL, 'f' },
{ "addr" , 1, NULL, 'a' },
{ "bits" , 1, NULL, 'b' },
+ { "describe" , 1, NULL, 'd' },
{ "list" , 0, NULL, 'l' },
{ "list-each" , 0, NULL, 'L' },
{ "no-summary", 0, NULL, 'N' },
@@ -907,7 +922,7 @@
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 +939,10 @@
case 'b':
parse_bits_mask(optarg);
break;
+ case 'd':
+ opt_no_summary = 1;
+ describe_flags(optarg);
+ break;
case 'l':
opt_list = 1;
break;