On Tue 2014-07-22 06:48:22, Alex Elder wrote: > On 07/21/2014 08:02 AM, Alex Elder wrote: > > Two global variables, "syslog_prev" and "console_prev", maintain a > > copy of the flags value used in the log record most recently > > formatted for syslog or the console, respectively. > > > > Initially there is no previous formatted log record, and these > > variables simply have an initial value 0. And occasionally log > > records can get consumed at a rate such that syslog or the console > > can't keep up, in which case those variables (along with their > > corresponding position variables) must be reset. Here too, they're > > reset to 0. > > > > This patch changes it so the initial value used is LOG_NEWLINE. > > That is, if we know nothing about the prevously-formatted log > > record, we can assume it was complete, and ended with a newline. > > One exception is that occasionally we reset our syslog or console > > (etc.) position variables. In that case the previously-formatted > > record flags value is still valid, so we preserve that information. > > > > This is being done to support the next patch. Initializing > > these variables this way makes LOG_NEWLINE and LOG_CONT be > > mutually exclusive, and the next patch uses that fact to simplify > > some logic. > > > > Signed-off-by: Alex Elder <[email protected]> > > Reviewed-by: Petr Mládek <[email protected]> > > I have one change I'd like to suggest on this one. > > Petr, could you offer your opinion? > > > > --- > > kernel/printk/printk.c | 44 ++++++++++++++++++++++++++++++-------------- > > 1 file changed, 30 insertions(+), 14 deletions(-) > > > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > > index 9f11eab..2f43116 100644 > > --- a/kernel/printk/printk.c > > +++ b/kernel/printk/printk.c > > > . . . > > > @@ -2156,10 +2168,14 @@ again: > > "%s** %u printk messages dropped **\n", > > (console_prev & LOG_CONT) ? "\n" : "", > > (unsigned)(log_first_seq - console_seq)); > > - /* messages are gone, move to first one */ > > + /* > > + * Messages are gone, move to first one. > > + * Don't discard what we know about the > > + * previously-formatted record. > > + */ > > console_seq = log_first_seq; > > console_idx = log_first_idx; > > - console_prev = 0; > > + console_prev &= LOG_NEWLINE|LOG_CONT; > > In this one spot, I think console_prev should simply be > initialized with LOG_NEWLINE. > > The reason is that the "printk messages dropped" message will > be inserted into the formatted output, and is hence the last > formatted line. And that message is (now) terminated with > a newline.
Sure. Great catch! I actually mentioned it when commenting v4, see https://lkml.org/lkml/2014/7/21/153 . But I forgot it today :-/ Best Regards, Petr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
