Re: network driver usage count
David Miller <[EMAIL PROTECTED]> writes: > From: Wagner Ferenc <[EMAIL PROTECTED]> > Date: Wed, 21 Nov 2007 23:16:59 +0100 > >> Hmm, that would warrant nuking all the reference counts on every >> driver. > > That's not true. When packets are in flight, references go > to the device and the device cannot be unloaded until those > references get dropped. I'm trying to understand it. Do you mean that the "usage count" in the lsmod output does not express the user's view of a piece of *ware being in use, but rather the number of internal kernel references to it, which would become invalid should that piece disappear? Where the former "invalidily" means some undetectable and uncorrectable inconsistency in the kernel data structures, which leads to a kernel crash. > This behavior makes sense because otherwise you have to figure > out the myriad of references (each ipv4 address, each ipv6 > address, routes, ARP entries, etc.) just to perform such a > simple operation. Yes, that's the user's idea of a network device being in use. It can get hairy indeed. > If you do not mean to unload the device, simply do not do it. Now I know... -- Thanks for taking the time, Feri. - 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/
Re: network driver usage count
David Miller [EMAIL PROTECTED] writes: From: Wagner Ferenc [EMAIL PROTECTED] Date: Wed, 21 Nov 2007 23:16:59 +0100 Hmm, that would warrant nuking all the reference counts on every driver. That's not true. When packets are in flight, references go to the device and the device cannot be unloaded until those references get dropped. I'm trying to understand it. Do you mean that the usage count in the lsmod output does not express the user's view of a piece of *ware being in use, but rather the number of internal kernel references to it, which would become invalid should that piece disappear? Where the former invalidily means some undetectable and uncorrectable inconsistency in the kernel data structures, which leads to a kernel crash. This behavior makes sense because otherwise you have to figure out the myriad of references (each ipv4 address, each ipv6 address, routes, ARP entries, etc.) just to perform such a simple operation. Yes, that's the user's idea of a network device being in use. It can get hairy indeed. If you do not mean to unload the device, simply do not do it. Now I know... -- Thanks for taking the time, Feri. - 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/
Re: network driver usage count
From: Wagner Ferenc <[EMAIL PROTECTED]> Date: Wed, 21 Nov 2007 23:16:59 +0100 > Hmm, that would warrant nuking all the reference counts on every > driver. That's not true. When packets are in flight, references go to the device and the device cannot be unloaded until those references get dropped. This behavior makes sense because otherwise you have to figure out the myriad of references (each ipv4 address, each ipv6 address, routes, ARP entries, etc.) just to perform such a simple operation. If you do not mean to unload the device, simply do not do it. - 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/
Re: network driver usage count
From: Wagner Ferenc [EMAIL PROTECTED] Date: Wed, 21 Nov 2007 23:16:59 +0100 Hmm, that would warrant nuking all the reference counts on every driver. That's not true. When packets are in flight, references go to the device and the device cannot be unloaded until those references get dropped. This behavior makes sense because otherwise you have to figure out the myriad of references (each ipv4 address, each ipv6 address, routes, ARP entries, etc.) just to perform such a simple operation. If you do not mean to unload the device, simply do not do it. - 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/
Re: network driver usage count
Wagner Ferenc <[EMAIL PROTECTED]> : [...] > So why can I remove a driver serving live network traffic? Why not ? It is quite common to remove physically a network/storage device. -- Ueimor - 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/
Re: network driver usage count
Stephen Hemminger <[EMAIL PROTECTED]> writes: > On Wed, 21 Nov 2007 20:45:11 +0100 > Ferenc Wagner <[EMAIL PROTECTED]> wrote: > >> Under 2.6.23.1, my lsmod output shows this: >> >> $ lsmod | grep tg3 >> tg3 100580 0 >> >> The usage count is zero, even though it drives my two physical >> interfaces: >> >> $ ls -l /sys/class/net/eth-gb?/device/driver >> lrwxrwxrwx 1 root root 0 2007-11-21 19:58 >> /sys/class/net/eth-gb1/device/driver -> ../../../bus/pci/drivers/tg3 >> lrwxrwxrwx 1 root root 0 2007-11-21 19:58 >> /sys/class/net/eth-gb2/device/driver -> ../../../bus/pci/drivers/tg3 >> >> These interfaces are up and bonded together, but that doesn't seem to >> matter at all. I also checked other machines, the network driver >> (tg3, e1000) usage counts are always zero under various recent 2.6 >> kernels, but nonzero under 2.4.21 for example. >> >> And really, the module could be removed, cutting my ssh session. :) >> >> Was this made possible intentionally? If yes, why? > > Yes, so devices can be removed at anytime. Hmm, that would warrant nuking all the reference counts on every driver. I must be missing something, since I really feel it goes against common sense. Can you point me to some discussion of this change? I mean, I couldn't remove the driver of a mounted filesystem. So why can I remove a driver serving live network traffic? -- Thanks, Feri. - 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/
Re: network driver usage count
On Wed, 21 Nov 2007 20:45:11 +0100 Ferenc Wagner <[EMAIL PROTECTED]> wrote: > Hi! > > Under 2.6.23.1, my lsmod output shows this: > > $ lsmod | grep tg3 > tg3 100580 0 > > The usage count is zero, even though it drives my two physical > interfaces: > > $ ls -l /sys/class/net/eth-gb?/device/driver > lrwxrwxrwx 1 root root 0 2007-11-21 19:58 > /sys/class/net/eth-gb1/device/driver -> ../../../bus/pci/drivers/tg3 > lrwxrwxrwx 1 root root 0 2007-11-21 19:58 > /sys/class/net/eth-gb2/device/driver -> ../../../bus/pci/drivers/tg3 > > These interfaces are up and bonded together, but that doesn't seem to > matter at all. I also checked other machines, the network driver > (tg3, e1000) usage counts are always zero under various recent 2.6 > kernels, but nonzero under 2.4.21 for example. > > And really, the module could be removed, cutting my ssh session. :) > > Was this made possible intentionally? If yes, why? Yes, so devices can be removed at anytime. -- Stephen Hemminger <[EMAIL PROTECTED]> - 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/
Re: network driver usage count
On Wed, 21 Nov 2007 20:45:11 +0100 Ferenc Wagner [EMAIL PROTECTED] wrote: Hi! Under 2.6.23.1, my lsmod output shows this: $ lsmod | grep tg3 tg3 100580 0 The usage count is zero, even though it drives my two physical interfaces: $ ls -l /sys/class/net/eth-gb?/device/driver lrwxrwxrwx 1 root root 0 2007-11-21 19:58 /sys/class/net/eth-gb1/device/driver - ../../../bus/pci/drivers/tg3 lrwxrwxrwx 1 root root 0 2007-11-21 19:58 /sys/class/net/eth-gb2/device/driver - ../../../bus/pci/drivers/tg3 These interfaces are up and bonded together, but that doesn't seem to matter at all. I also checked other machines, the network driver (tg3, e1000) usage counts are always zero under various recent 2.6 kernels, but nonzero under 2.4.21 for example. And really, the module could be removed, cutting my ssh session. :) Was this made possible intentionally? If yes, why? Yes, so devices can be removed at anytime. -- Stephen Hemminger [EMAIL PROTECTED] - 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/
Re: network driver usage count
Stephen Hemminger [EMAIL PROTECTED] writes: On Wed, 21 Nov 2007 20:45:11 +0100 Ferenc Wagner [EMAIL PROTECTED] wrote: Under 2.6.23.1, my lsmod output shows this: $ lsmod | grep tg3 tg3 100580 0 The usage count is zero, even though it drives my two physical interfaces: $ ls -l /sys/class/net/eth-gb?/device/driver lrwxrwxrwx 1 root root 0 2007-11-21 19:58 /sys/class/net/eth-gb1/device/driver - ../../../bus/pci/drivers/tg3 lrwxrwxrwx 1 root root 0 2007-11-21 19:58 /sys/class/net/eth-gb2/device/driver - ../../../bus/pci/drivers/tg3 These interfaces are up and bonded together, but that doesn't seem to matter at all. I also checked other machines, the network driver (tg3, e1000) usage counts are always zero under various recent 2.6 kernels, but nonzero under 2.4.21 for example. And really, the module could be removed, cutting my ssh session. :) Was this made possible intentionally? If yes, why? Yes, so devices can be removed at anytime. Hmm, that would warrant nuking all the reference counts on every driver. I must be missing something, since I really feel it goes against common sense. Can you point me to some discussion of this change? I mean, I couldn't remove the driver of a mounted filesystem. So why can I remove a driver serving live network traffic? -- Thanks, Feri. - 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/
Re: network driver usage count
Wagner Ferenc [EMAIL PROTECTED] : [...] So why can I remove a driver serving live network traffic? Why not ? It is quite common to remove physically a network/storage device. -- Ueimor - 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/
