From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755860AbZKDMpq (ORCPT ); Wed, 4 Nov 2009 07:45:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755781AbZKDMpp (ORCPT ); Wed, 4 Nov 2009 07:45:45 -0500 Received: from mga14.intel.com ([143.182.124.37]:23973 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753787AbZKDMpp (ORCPT ); Wed, 4 Nov 2009 07:45:45 -0500 X-ExtLoop1: 1 Date: Wed, 4 Nov 2009 20:18:32 +0800 From: Wu Fengguang To: Alex Chiang , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andi Kleen , "Li, Haicheng" Subject: Re: [PATCH] page-types: decode flags directly from command line Message-ID: <20091104121832.GB26504@localhost> References: <20091103225441.GB4087@grease> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091103225441.GB4087@grease> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alex, On Wed, Nov 04, 2009 at 06:54:41AM +0800, Alex Chiang wrote: > Teach page-types to decode page flags directly from the command > line. This is good feature to have - I considered adding it, too ;) > > 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. In fact it's more than decode - encoding is also possible with the _same_ code! So maybe "-d" and help message will not be all that appropriate. > 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 The output is a bit redundant - so does the code. Could you simplify them a bit? Thanks, Fengguang > Signed-off-by: Alex Chiang > --- > 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;