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From: Greg Kroah-Hartmann <greg@kroah.com>
To: Kay Sievers <kay@vrfy.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH RESEND 2/3] kmsg: export printk records to the /dev/kmsg interface
Date: Mon, 7 May 2012 17:28:30 -0700	[thread overview]
Message-ID: <20120508002830.GA2204@kroah.com> (raw)
In-Reply-To: <1336004981.4240.10.camel@mop>

On Thu, May 03, 2012 at 02:29:41AM +0200, Kay Sievers wrote:
> From: Kay Sievers <kay@vrfy.org>
> Subject: kmsg: export printk records to the /dev/kmsg interface
> 
> Support for multiple concurrent readers of /dev/kmsg, with read(),
> seek(), poll() support. Output of message sequence numbers, to allow
> userspace log consumers to reliably reconnect and reconstruct their
> state at any given time. After open("/dev/kmsg"), read() always
> returns *all* buffered records. If only future messages should be
> read, SEEK_END can be used. In case records get overwritten while
> /dev/kmsg is held open, or records get faster overwritten than they
> are read, the next read() will return -EPIPE and the current reading
> position gets updated to the next available record. The passed
> sequence numbers allow the log consumer to calculate the amount of
> lost messages.
> 
>   [root@mop ~]# cat /dev/kmsg
>   5,0,0;Linux version 3.4.0-rc1+ (kay@mop) (gcc version 4.7.0 20120315 ...
>   6,159,423091;ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
>   7,160,424069;pci_root PNP0A03:00: host bridge window [io  0x0000-0x0cf7] (ignored)
>    SUBSYSTEM=acpi
>    DEVICE=+acpi:PNP0A03:00
>   6,339,5140900;NET: Registered protocol family 10
>   30,340,5690716;udevd[80]: starting version 181
>   6,341,6081421;FDC 0 is a S82078B
>   6,345,6154686;microcode: CPU0 sig=0x623, pf=0x0, revision=0x0
>   7,346,6156968;sr 1:0:0:0: Attached scsi CD-ROM sr0
>    SUBSYSTEM=scsi
>    DEVICE=+scsi:1:0:0:0
>   6,347,6289375;microcode: CPU1 sig=0x623, pf=0x0, revision=0x0

Can you add a file somwhere in Documentation (Documentatin/ABI?) that
documents the file format for this file?

Other than that, nice, I've queued all of these up.

thanks,

greg k-h

  reply	other threads:[~2012-05-08  0:28 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-03  0:29 [PATCH RESEND 2/3] kmsg: export printk records to the /dev/kmsg interface Kay Sievers
2012-05-08  0:28 ` Greg Kroah-Hartmann [this message]
2012-05-08 16:50   ` Kay Sievers
2012-05-08 17:00     ` Greg Kroah-Hartmann
2012-05-10 11:45 ` Dan Carpenter
2012-05-10 16:05   ` Linus Torvalds

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