Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2 May 2018, John Stoffel wrote: > You miss my point, which is that there's no explanation of what the > difference is between SLAB and SLUB and which I should choose. The > same goes here. If the KConfig option doesn't give useful info, it's > useless. So what, we could write

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2 May 2018, John Stoffel wrote: > You miss my point, which is that there's no explanation of what the > difference is between SLAB and SLUB and which I should choose. The > same goes here. If the KConfig option doesn't give useful info, it's > useless. So what, we could write

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "Mikulas" == Mikulas Patocka writes: Mikulas> On Mon, 30 Apr 2018, John Stoffel wrote: >> > "Mikulas" == Mikulas Patocka writes: >> Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: >> Mikulas> I see your point - and I think the

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "Mikulas" == Mikulas Patocka writes: Mikulas> On Mon, 30 Apr 2018, John Stoffel wrote: >> > "Mikulas" == Mikulas Patocka writes: >> Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: >> Mikulas> I see your point - and I think the misunderstanding is this. >> >> Thanks. >> Mikulas>

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Mon, 30 Apr 2018, John Stoffel wrote: > > "Mikulas" == Mikulas Patocka writes: > > Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: > > Mikulas> I see your point - and I think the misunderstanding is this. > > Thanks. > > Mikulas> This patch is not really

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Mon, 30 Apr 2018, John Stoffel wrote: > > "Mikulas" == Mikulas Patocka writes: > > Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: > > Mikulas> I see your point - and I think the misunderstanding is this. > > Thanks. > > Mikulas> This patch is not really helping people to debug

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "Mikulas" == Mikulas Patocka writes: Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: >> > "James" == James Bottomley >> > writes: >> James> I may be an atypical developer but I'd rather have a root canal James> than

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "Mikulas" == Mikulas Patocka writes: Mikulas> On Thu, 26 Apr 2018, John Stoffel wrote: >> > "James" == James Bottomley >> > writes: >> James> I may be an atypical developer but I'd rather have a root canal James> than browse through menuconfig options. The way to get people

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > 2. Ability to control this from a separate config >option. > >It's still not that clear to me why is this such a >hard requirement. If a distro wants to force specific >boot time options, why isn't CONFIG_CMDLINE sufficient?

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > 2. Ability to control this from a separate config >option. > >It's still not that clear to me why is this such a >hard requirement. If a distro wants to force specific >boot time options, why isn't CONFIG_CMDLINE sufficient?

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michal Hocko wrote: > On Thu 26-04-18 18:52:05, Mikulas Patocka wrote: > > > > > > On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > [...] > > >But assuming it's important to control this kind of > > >fault injection to be controlled from > > >a dedicated

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michal Hocko wrote: > On Thu 26-04-18 18:52:05, Mikulas Patocka wrote: > > > > > > On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > [...] > > >But assuming it's important to control this kind of > > >fault injection to be controlled from > > >a dedicated

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu 26-04-18 18:52:05, Mikulas Patocka wrote: > > > On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: [...] > >But assuming it's important to control this kind of > >fault injection to be controlled from > >a dedicated menuconfig option, why not the rest of > >faults? > > The

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu 26-04-18 18:52:05, Mikulas Patocka wrote: > > > On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: [...] > >But assuming it's important to control this kind of > >fault injection to be controlled from > >a dedicated menuconfig option, why not the rest of > >faults? > > The

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 05:50:20PM -0400, Mikulas Patocka wrote: > > How is the user or developer supposed to learn about this option, if > > he gets no crash at all? > > Look in /sys/kernel/debug/fail* ? That actually lets you > filter by

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Fri, 27 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 05:50:20PM -0400, Mikulas Patocka wrote: > > How is the user or developer supposed to learn about this option, if > > he gets no crash at all? > > Look in /sys/kernel/debug/fail* ? That actually lets you > filter by

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 05:50:20PM -0400, Mikulas Patocka wrote: > How is the user or developer supposed to learn about this option, if > he gets no crash at all? Look in /sys/kernel/debug/fail* ? That actually lets you filter by module, process etc. I think this patch conflates two things: 1.

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 05:50:20PM -0400, Mikulas Patocka wrote: > How is the user or developer supposed to learn about this option, if > he gets no crash at all? Look in /sys/kernel/debug/fail* ? That actually lets you filter by module, process etc. I think this patch conflates two things: 1.

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, John Stoffel wrote: > > "James" == James Bottomley > > writes: > > James> I may be an atypical developer but I'd rather have a root canal > James> than browse through menuconfig options. The way to get people > James> to

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, John Stoffel wrote: > > "James" == James Bottomley > > writes: > > James> I may be an atypical developer but I'd rather have a root canal > James> than browse through menuconfig options. The way to get people > James> to learn about new debugging options is to

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 03:36:14PM -0400, Mikulas Patocka wrote: > > People on this list argue "this should be a kernel parameter". > > How about making it a writeable attribute, so it's easy to turn on/off > after boot. Then you can keep it

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 03:36:14PM -0400, Mikulas Patocka wrote: > > People on this list argue "this should be a kernel parameter". > > How about making it a writeable attribute, so it's easy to turn on/off > after boot. Then you can keep it

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 03:36:14PM -0400, Mikulas Patocka wrote: > People on this list argue "this should be a kernel parameter". How about making it a writeable attribute, so it's easy to turn on/off after boot. Then you can keep it deterministic, userspace can play with the attribute at random

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 03:36:14PM -0400, Mikulas Patocka wrote: > People on this list argue "this should be a kernel parameter". How about making it a writeable attribute, so it's easy to turn on/off after boot. Then you can keep it deterministic, userspace can play with the attribute at random

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 02:54:26PM -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > > > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > > > IIUC debug kernels mainly exist so

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 02:54:26PM -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > > > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > > > IIUC debug kernels mainly exist so

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "James" == James Bottomley writes: James> On Wed, 2018-04-25 at 19:00 -0400, Mikulas Patocka wrote: >> >> On Wed, 25 Apr 2018, James Bottomley wrote: >> >> > > > Do we really need the new config option?  This could just be >> > > > manually  tunable

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

> "James" == James Bottomley writes: James> On Wed, 2018-04-25 at 19:00 -0400, Mikulas Patocka wrote: >> >> On Wed, 25 Apr 2018, James Bottomley wrote: >> >> > > > Do we really need the new config option?  This could just be >> > > > manually  tunable via fault injection IIUC. >> > >  >> >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 02:54:26PM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > > IIUC debug kernels mainly exist so people who experience e.g. memory > > > > corruption can try

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 02:54:26PM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > > IIUC debug kernels mainly exist so people who experience e.g. memory > > > > corruption can try

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 02:58:08PM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > How do you make sure QA tests a specific corner case? Add it to > > the test plan :) > > BTW. how many "lines of code" of corporate bureaucracy would that take? :-) It's

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 02:58:08PM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > > > How do you make sure QA tests a specific corner case? Add it to > > the test plan :) > > BTW. how many "lines of code" of corporate bureaucracy would that take? :-) It's

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > How do you make sure QA tests a specific corner case? Add it to > the test plan :) BTW. how many "lines of code" of corporate bureaucracy would that take? :-) > I don't speak for Red Hat, etc. > > -- > MST Mikulas

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > How do you make sure QA tests a specific corner case? Add it to > the test plan :) BTW. how many "lines of code" of corporate bureaucracy would that take? :-) > I don't speak for Red Hat, etc. > > -- > MST Mikulas

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > IIUC debug kernels mainly exist so people who experience e.g. memory > > > corruption can try and debug the failure. In this case, CONFIG_DEBUG_SG > > > will *already* catch a

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > > IIUC debug kernels mainly exist so people who experience e.g. memory > > > corruption can try and debug the failure. In this case, CONFIG_DEBUG_SG > > > will *already* catch a

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > IIUC debug kernels mainly exist so people who experience e.g. memory > > corruption can try and debug the failure. In this case, CONFIG_DEBUG_SG > > will *already* catch a failure early. Nothing special needs to be done. > > The

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 12:07:25PM -0400, Mikulas Patocka wrote: > > IIUC debug kernels mainly exist so people who experience e.g. memory > > corruption can try and debug the failure. In this case, CONFIG_DEBUG_SG > > will *already* catch a failure early. Nothing special needs to be done. > > The

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 11:44:21AM -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > > > > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > > > > > On Thu, 26 Apr 2018, James Bottomley

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michael S. Tsirkin wrote: > On Thu, Apr 26, 2018 at 11:44:21AM -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > > > > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > > > > > On Thu, 26 Apr 2018, James Bottomley

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 11:44:21AM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > [...] > > > > Perhaps find out beforehand instead of

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, Apr 26, 2018 at 11:44:21AM -0400, Mikulas Patocka wrote: > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > > [...] > > > > Perhaps find out beforehand instead of

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > So you're shifting your argument from "I have to do it as a Kconfig > option because the distros require it" to "distributions will build > separate kernel packages for this, but won't do enabling in a non > kernel package"? To be honest, I think

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > So you're shifting your argument from "I have to do it as a Kconfig > option because the distros require it" to "distributions will build > separate kernel packages for this, but won't do enabling in a non > kernel package"? To be honest, I think

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > [...] > > > Perhaps find out beforehand instead of insisting on an approach > > without > > > knowing.  On openSUSE the grub config is

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > > > On Thu, 26 Apr 2018, James Bottomley wrote: > [...] > > > Perhaps find out beforehand instead of insisting on an approach > > without > > > knowing.  On openSUSE the grub config is

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > On Thu, 26 Apr 2018, James Bottomley wrote: [...] > > Perhaps find out beforehand instead of insisting on an approach > without > > knowing.  On openSUSE the grub config is built from the files in > > /etc/grub.d/ so any package can

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 2018-04-26 at 11:05 -0400, Mikulas Patocka wrote: > > On Thu, 26 Apr 2018, James Bottomley wrote: [...] > > Perhaps find out beforehand instead of insisting on an approach > without > > knowing.  On openSUSE the grub config is built from the files in > > /etc/grub.d/ so any package can

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Mikulas Patocka wrote: > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > > BTW. even developers who compile their own kernel should have this > > > enabled by a CONFIG option - because if the developer sees the option > > > when browsing through menuconfig, he may

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Mikulas Patocka wrote: > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > > BTW. even developers who compile their own kernel should have this > > > enabled by a CONFIG option - because if the developer sees the option > > > when browsing through menuconfig, he may

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > On Thu, 2018-04-26 at 10:28 -0400, Mikulas Patocka wrote: > > > > On Thu, 26 Apr 2018, Michal Hocko wrote: > > > > > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > >  > > > >  > > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > [...]

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, James Bottomley wrote: > On Thu, 2018-04-26 at 10:28 -0400, Mikulas Patocka wrote: > > > > On Thu, 26 Apr 2018, Michal Hocko wrote: > > > > > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > >  > > > >  > > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > [...]

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > > BTW. even developers who compile their own kernel should have this > > enabled by a CONFIG option - because if the developer sees the option > > when browsing through menuconfig, he may enable it. If he doesn't see > > the option, he won't even

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > > BTW. even developers who compile their own kernel should have this > > enabled by a CONFIG option - because if the developer sees the option > > when browsing through menuconfig, he may enable it. If he doesn't see > > the option, he won't even

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 2018-04-26 at 10:28 -0400, Mikulas Patocka wrote: > > On Thu, 26 Apr 2018, Michal Hocko wrote: > > > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > >  > > >  > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > [...] > > > > Kconfig proliferation, conversely, is a bit of a

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 2018-04-26 at 10:28 -0400, Mikulas Patocka wrote: > > On Thu, 26 Apr 2018, Michal Hocko wrote: > > > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > >  > > >  > > > On Wed, 25 Apr 2018, James Bottomley wrote: > > [...] > > > > Kconfig proliferation, conversely, is a bit of a

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michal Hocko wrote: > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > > > > On Wed, 25 Apr 2018, James Bottomley wrote: > [...] > > > Kconfig proliferation, conversely, is a bit of a nightmare from both > > > the user and the tester's point of view, so we're trying

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Thu, 26 Apr 2018, Michal Hocko wrote: > On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > > > > On Wed, 25 Apr 2018, James Bottomley wrote: > [...] > > > Kconfig proliferation, conversely, is a bit of a nightmare from both > > > the user and the tester's point of view, so we're trying

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > On Wed, 25 Apr 2018, James Bottomley wrote: [...] > > Kconfig proliferation, conversely, is a bit of a nightmare from both > > the user and the tester's point of view, so we're trying to avoid it > > unless absolutely necessary. > > > >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed 25-04-18 18:42:57, Mikulas Patocka wrote: > > > On Wed, 25 Apr 2018, James Bottomley wrote: [...] > > Kconfig proliferation, conversely, is a bit of a nightmare from both > > the user and the tester's point of view, so we're trying to avoid it > > unless absolutely necessary. > > > >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2018-04-25 at 19:00 -0400, Mikulas Patocka wrote: > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > > > Do we really need the new config option?  This could just be > > > > manually  tunable via fault injection IIUC. > > >  > > > We do, because we want to enable it in RHEL and Fedora

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2018-04-25 at 19:00 -0400, Mikulas Patocka wrote: > > On Wed, 25 Apr 2018, James Bottomley wrote: > > > > > Do we really need the new config option?  This could just be > > > > manually  tunable via fault injection IIUC. > > >  > > > We do, because we want to enable it in RHEL and Fedora

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > > > Do we really need the new config option?  This could just be > > > manually  tunable via fault injection IIUC. > > > > We do, because we want to enable it in RHEL and Fedora debugging > > kernels, so that it will be tested by the users. > > >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > > > Do we really need the new config option?  This could just be > > > manually  tunable via fault injection IIUC. > > > > We do, because we want to enable it in RHEL and Fedora debugging > > kernels, so that it will be tested by the users. > > >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, David Rientjes wrote: > On Wed, 25 Apr 2018, Mikulas Patocka wrote: > > > You need to enable it on boot. Enabling it when the kernel starts to > > execute userspace code is already too late (because you would miss > > kvmalloc calls in the kernel boot path). > > Is your

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, David Rientjes wrote: > On Wed, 25 Apr 2018, Mikulas Patocka wrote: > > > You need to enable it on boot. Enabling it when the kernel starts to > > execute userspace code is already too late (because you would miss > > kvmalloc calls in the kernel boot path). > > Is your

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, Mikulas Patocka wrote: > You need to enable it on boot. Enabling it when the kernel starts to > execute userspace code is already too late (because you would miss > kvmalloc calls in the kernel boot path). > Is your motivation that since kvmalloc() never falls back to

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, Mikulas Patocka wrote: > You need to enable it on boot. Enabling it when the kernel starts to > execute userspace code is already too late (because you would miss > kvmalloc calls in the kernel boot path). > Is your motivation that since kvmalloc() never falls back to

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > On Wed, 2018-04-25 at 17:22 -0400, Mikulas Patocka wrote: > > > > On Wed, 25 Apr 2018, David Rientjes wrote: > > > > > > Do we really need the new config option?  This could just be > > > manually  tunable via fault injection IIUC. > > > > We do,

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 25 Apr 2018, James Bottomley wrote: > On Wed, 2018-04-25 at 17:22 -0400, Mikulas Patocka wrote: > > > > On Wed, 25 Apr 2018, David Rientjes wrote: > > > > > > Do we really need the new config option?  This could just be > > > manually  tunable via fault injection IIUC. > > > > We do,

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2018-04-25 at 17:22 -0400, Mikulas Patocka wrote: > > On Wed, 25 Apr 2018, David Rientjes wrote: > > > On Wed, 25 Apr 2018, Mikulas Patocka wrote: > > > > > From: Mikulas Patocka > > > Subject: [PATCH] fault-injection: introduce kvmalloc fallback > > > options > >

Re: [dm-devel] [PATCH v5] fault-injection: introduce kvmalloc fallback options

On Wed, 2018-04-25 at 17:22 -0400, Mikulas Patocka wrote: > > On Wed, 25 Apr 2018, David Rientjes wrote: > > > On Wed, 25 Apr 2018, Mikulas Patocka wrote: > > > > > From: Mikulas Patocka > > > Subject: [PATCH] fault-injection: introduce kvmalloc fallback > > > options > > > > > > This patch