On (06/30/17 21:35), Tetsuo Handa wrote: > Date: Fri, 30 Jun 2017 21:35:28 +0900 > From: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp> > To: sergey.senozhatsky.w...@gmail.com > Cc: pmla...@suse.com, sergey.senozhat...@gmail.com, rost...@goodmis.org, > j...@suse.cz, a...@linux-foundation.org, pet...@infradead.org, > r...@rjwysocki.net, ebied...@xmission.com, gre...@linuxfoundation.org, > jsl...@suse.com, pa...@ucw.cz, a...@lisas.de, linux-kernel@vger.kernel.org > Subject: Re: [RFC][PATCHv3 2/5] printk: introduce printing kernel thread > X-Mailer: Winbiff [Version 2.51 PL2] > > Sergey Senozhatsky wrote: > > On (06/30/17 19:18), Tetsuo Handa wrote: > > > > I'm still thinking about Steven's proposals; but we will need offloading > > > > anyways, so the bits we are talking about here are important regardless > > > > the direction printk design will take, I think. > > > > > > Is there a chance that printk() waits for only data queued by that > > > printk() > > > call (exception will be printk() from NMI). > > > > hm, I don't think this can be done easily... consider > > > > console_lock(); > > printk(); > > printk(); > > ... -> this guys will wait forever. nothing > > flushes the logbuf. > > printk(); > > console_unlock(); > > Can't we remove console_lock()/console_unlock() from printk() ?
we can't... well, we can... and there are some ideas but we are years away from all it becoming reality. console_sem is the giant and major lock that fbcon, drm, tty and so on are using. please see a sub-thread starting from here: https://lists.linuxfoundation.org/pipermail/ksummit-discuss/2017-June/004389.html > I think that printk() depends on console_unlock() is complicating. it absolutely is. -ss
