Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu 2015-10-22 14:19:26, David Howells wrote: > Petr Mladek wrote: > > > I would expect that the first few messages are printed to the console > > before the buffer is wrapped. IMHO, in many cases, you are interested > > into the final messages that describe why the system went down. > > The

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu 2015-10-22 14:19:26, David Howells wrote: > Petr Mladek wrote: > > > I would expect that the first few messages are printed to the console > > before the buffer is wrapped. IMHO, in many cases, you are interested > > into the final messages that describe why the system

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 14:19 +0100, David Howells wrote: > Petr Mladek wrote: > > > I would expect that the first few messages are printed to the console > > before the buffer is wrapped. IMHO, in many cases, you are interested > > into the final messages that describe why the system went down. >

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

Petr Mladek wrote: > I would expect that the first few messages are printed to the console > before the buffer is wrapped. IMHO, in many cases, you are interested > into the final messages that describe why the system went down. The last message might tell you that the machine panicked because

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 14:18 +0200, Jan Kara wrote: > > > > > What happened to it? And how do we fix it? > > Hard to fix since you'd easily get RCU stalls and softlockup messages on > systems with lots of CPUs and heavy printk traffic... If we have to explicitly opt in to synchronous output,

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

Added Andrew into CC who maintains printk() code. On Thu 2015-10-22 11:16:50, David Howells wrote: > printk() currently discards earlier messages to make space for new messages > arriving. This has the distinct downside that if the kernel starts > churning out messages because of some initial

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu 22-10-15 11:28:47, David Woodhouse wrote: > On Thu, 2015-10-22 at 11:16 +0100, David Howells wrote: > > printk() currently discards earlier messages to make space for new messages > > arriving. This has the distinct downside that if the kernel starts > > churning out messages because of

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 11:16 +0100, David Howells wrote: > printk() currently discards earlier messages to make space for new messages > arriving. This has the distinct downside that if the kernel starts > churning out messages because of some initial incident, the report of the > initial incident

[PATCH] printk: Don't discard earlier unprinted messages to make space

printk() currently discards earlier messages to make space for new messages arriving. This has the distinct downside that if the kernel starts churning out messages because of some initial incident, the report of the initial incident is likely to be lost under a blizzard of: ** NNN

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 11:16 +0100, David Howells wrote: > printk() currently discards earlier messages to make space for new messages > arriving. This has the distinct downside that if the kernel starts > churning out messages because of some initial incident, the report of the > initial incident

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu 22-10-15 11:28:47, David Woodhouse wrote: > On Thu, 2015-10-22 at 11:16 +0100, David Howells wrote: > > printk() currently discards earlier messages to make space for new messages > > arriving. This has the distinct downside that if the kernel starts > > churning out messages because of

[PATCH] printk: Don't discard earlier unprinted messages to make space

printk() currently discards earlier messages to make space for new messages arriving. This has the distinct downside that if the kernel starts churning out messages because of some initial incident, the report of the initial incident is likely to be lost under a blizzard of: ** NNN

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 14:18 +0200, Jan Kara wrote: > > > > > What happened to it? And how do we fix it? > > Hard to fix since you'd easily get RCU stalls and softlockup messages on > systems with lots of CPUs and heavy printk traffic... If we have to explicitly opt in to synchronous output,

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

On Thu, 2015-10-22 at 14:19 +0100, David Howells wrote: > Petr Mladek wrote: > > > I would expect that the first few messages are printed to the console > > before the buffer is wrapped. IMHO, in many cases, you are interested > > into the final messages that describe why the

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

Added Andrew into CC who maintains printk() code. On Thu 2015-10-22 11:16:50, David Howells wrote: > printk() currently discards earlier messages to make space for new messages > arriving. This has the distinct downside that if the kernel starts > churning out messages because of some initial

Re: [PATCH] printk: Don't discard earlier unprinted messages to make space

Petr Mladek wrote: > I would expect that the first few messages are printed to the console > before the buffer is wrapped. IMHO, in many cases, you are interested > into the final messages that describe why the system went down. The last message might tell you that the machine