| Message ID | 3d99e1291b3bc8f2a78467d11b1a7a31393180fc.1589086800.git.riteshh@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ext4: mballoc/extents: Code cleanup and debug improvements | expand |
On Sun, May 10, 2020 at 11:54:56AM +0530, Ritesh Harjani wrote: > This adds process name and pid for ext4_msg(). > I found this to be useful. For e.g. below print gives more > info about process name and pid. > > [ 7671.131912] [mount/12543] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr I'm not entirely sure about adding the command/pid at the beginning of the message. The way we do this in ext4_warning and ext4_err is to print that information like this: printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n", sb->s_id, function, line, current->comm, &vaf); ... and I wonder if it would make more sense to add something like to ext4_msg(), just out of consistency's sake. Which of the debugging messages were you finding this to be most helpful? - Ted
Hello Ted, Sorry about the long delay. Had taken some time off and was tinkering around with another hobby project. On 5/21/20 11:56 PM, Theodore Y. Ts'o wrote: > On Sun, May 10, 2020 at 11:54:56AM +0530, Ritesh Harjani wrote: >> This adds process name and pid for ext4_msg(). >> I found this to be useful. For e.g. below print gives more >> info about process name and pid. >> >> [ 7671.131912] [mount/12543] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr > > I'm not entirely sure about adding the command/pid at the beginning of > the message. The way we do this in ext4_warning and ext4_err is to > print that information like this: > > printk(KERN_CRIT > "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n", > sb->s_id, function, line, current->comm, &vaf); > > ... and I wonder if it would make more sense to add something like to > ext4_msg(), just out of consistency's sake. Which of the debugging > messages were you finding this to be most helpful? Well earlier ext4_mb_show_ac() was using ext4_msg() function. But I changed that to use mb_debug() msg in patch-14 of this series, since mb_debug() is meant for those debug msgs. So I am completely ok if we think this patch is unnecessary, that's also why I kept this patch at the end of the series to check opinion of others. FWIW, the mballoc issue which I was seeing was mostly due to a multi- threaded application. And without name/pid of the process/threads, it was difficult to identify which debug msgs belonged to which threads. For this reason I thought such info in ext4_msg() would also help in future. Thanks for taking both patch series! -ritesh
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index bf5fcb477f66..5067a47f4f46 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -756,7 +756,8 @@ void __ext4_msg(struct super_block *sb, va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; - printk("%sEXT4-fs (%s): %pV\n", prefix, sb->s_id, &vaf); + printk("%s [%s/%d] EXT4-fs (%s): %pV\n", prefix, current->comm, + task_pid_nr(current), sb->s_id, &vaf); va_end(args); }
This adds process name and pid for ext4_msg(). I found this to be useful. For e.g. below print gives more info about process name and pid. [ 7671.131912] [mount/12543] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: acl,user_xattr Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> --- fs/ext4/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)