<stefano.stabellini@eu.citrix.com>
2011-Sep-21 12:37 UTC
[Xen-devel] [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> The xen-platform-pci module is small and for PV on HVM guests is a requirement for xenbus. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> --- drivers/xen/Kconfig | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index 5f7ff8e..a64b8e8 100644 --- a/drivers/xen/Kconfig +++ b/drivers/xen/Kconfig @@ -138,9 +138,9 @@ config XEN_GRANT_DEV_ALLOC or as part of an inter-domain shared memory channel. config XEN_PLATFORM_PCI - tristate "xen platform pci device driver" + bool "xen platform pci device driver" depends on XEN_PVHVM && PCI - default m + default y help Driver for the Xen PCI Platform device: it is responsible for initializing xenbus and grant_table when running in a Xen HVM -- 1.7.2.3 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Sep-21 18:51 UTC
[Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote:> From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > The xen-platform-pci module is small and for PV on HVM guests is aHow small? Does it get removed from memory if it never gets loaded?> requirement for xenbus.Ok, should it then have a depency on XenBus as well? Linus does not like the ''default y'' very much. He actually dislikes it quite much as I found when he tore Dan''s behind about cleancache. .. so I think making it ''default n'' is a better option or perhaps making it depend on some other functionality? Or perhaps just remove the tristate/bool altogether so it gets activated if XEN_PVHVM is set? Or remove the XEN_PLATFORM_PCI config option completly and make the config files that build this driver be CONFIG_XENPVHM dependent?> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > --- > drivers/xen/Kconfig | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > index 5f7ff8e..a64b8e8 100644 > --- a/drivers/xen/Kconfig > +++ b/drivers/xen/Kconfig > @@ -138,9 +138,9 @@ config XEN_GRANT_DEV_ALLOC > or as part of an inter-domain shared memory channel. > > config XEN_PLATFORM_PCI > - tristate "xen platform pci device driver" > + bool "xen platform pci device driver" > depends on XEN_PVHVM && PCI > - default m > + default y > help > Driver for the Xen PCI Platform device: it is responsible for > initializing xenbus and grant_table when running in a Xen HVM > -- > 1.7.2.3_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ian Campbell
2011-Sep-21 19:08 UTC
[Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, 2011-09-21 at 19:51 +0100, Konrad Rzeszutek Wilk wrote:> On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote: > > From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > The xen-platform-pci module is small and for PV on HVM guests is a > > How small?IIRC it is single digit numbers of kb.> Does it get removed from memory if it never gets loaded? > > > requirement for xenbus. > > Ok, should it then have a depency on XenBus as well?xenbus can''t be a module (which is why allowing platform-pci to be is causing problems).> Linus does not like the ''default y'' very much. He actually dislikes > it quite much as I found when he tore Dan''s behind about cleancache.In particular case the option is gated on a dependency on another Xen option (PVHVM) which doesn''t default on. But if you do select PVHVM you certainly want this option, so I think that''s ok (why else would ''default y'' even exist?)> .. so I think making it ''default n'' is a better option or perhaps > making it depend on some other functionality? Or perhaps just remove > the tristate/bool altogether so it gets activated if XEN_PVHVM > is set? > > Or remove the XEN_PLATFORM_PCI config option completly and make the > config files that build this driver be CONFIG_XENPVHM dependent?That would work too. Even better would be to make it an invisible Kconfig symbol which PVHVM just selects. Ian.> > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > --- > > drivers/xen/Kconfig | 4 ++-- > > 1 files changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig > > index 5f7ff8e..a64b8e8 100644 > > --- a/drivers/xen/Kconfig > > +++ b/drivers/xen/Kconfig > > @@ -138,9 +138,9 @@ config XEN_GRANT_DEV_ALLOC > > or as part of an inter-domain shared memory channel. > > > > config XEN_PLATFORM_PCI > > - tristate "xen platform pci device driver" > > + bool "xen platform pci device driver" > > depends on XEN_PVHVM && PCI > > - default m > > + default y > > help > > Driver for the Xen PCI Platform device: it is responsible for > > initializing xenbus and grant_table when running in a Xen HVM > > -- > > 1.7.2.3_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Sep-21 21:10 UTC
[Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, Sep 21, 2011 at 08:08:15PM +0100, Ian Campbell wrote:> On Wed, 2011-09-21 at 19:51 +0100, Konrad Rzeszutek Wilk wrote: > > On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote: > > > From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > > > The xen-platform-pci module is small and for PV on HVM guests is a > > > > How small? > > IIRC it is single digit numbers of kb. > > > Does it get removed from memory if it never gets loaded? > > > > > requirement for xenbus. > > > > Ok, should it then have a depency on XenBus as well? > > xenbus can''t be a module (which is why allowing platform-pci to be is > causing problems). > > > Linus does not like the ''default y'' very much. He actually dislikes > > it quite much as I found when he tore Dan''s behind about cleancache. > > In particular case the option is gated on a dependency on another Xen > option (PVHVM) which doesn''t default on. But if you do select PVHVM you > certainly want this option, so I think that''s ok (why else would > ''default y'' even exist?) > > > .. so I think making it ''default n'' is a better option or perhaps > > making it depend on some other functionality? Or perhaps just remove > > the tristate/bool altogether so it gets activated if XEN_PVHVM > > is set? > > > > Or remove the XEN_PLATFORM_PCI config option completly and make the > > config files that build this driver be CONFIG_XENPVHM dependent? > > That would work too. Even better would be to make it an invisible > Kconfig symbol which PVHVM just selects.<nods> Or that since you can''t really do PVHVM without the platform PCI driver. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2011-Sep-21 22:49 UTC
Re: [Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On 09/21/2011 12:08 PM, Ian Campbell wrote:> On Wed, 2011-09-21 at 19:51 +0100, Konrad Rzeszutek Wilk wrote: >> On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote: >>> From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> >>> >>> The xen-platform-pci module is small and for PV on HVM guests is a >> How small? > IIRC it is single digit numbers of kb.lsmod shows it''s about 2.5k.>> Does it get removed from memory if it never gets loaded?Nope.>>> requirement for xenbus. >> Ok, should it then have a depency on XenBus as well? > xenbus can''t be a module (which is why allowing platform-pci to be is > causing problems). > >> Linus does not like the ''default y'' very much. He actually dislikes >> it quite much as I found when he tore Dan''s behind about cleancache. > In particular case the option is gated on a dependency on another Xen > option (PVHVM) which doesn''t default on. But if you do select PVHVM you > certainly want this option, so I think that''s ok (why else would > ''default y'' even exist?)It was default ''m'' before, so making it ''y'' is just the logical mapping of tristate->bool.>> .. so I think making it ''default n'' is a better option or perhaps >> making it depend on some other functionality? Or perhaps just remove >> the tristate/bool altogether so it gets activated if XEN_PVHVM >> is set? >> >> Or remove the XEN_PLATFORM_PCI config option completly and make the >> config files that build this driver be CONFIG_XENPVHM dependent? > That would work too. Even better would be to make it an invisible > Kconfig symbol which PVHVM just selects.Eh, select is pretty nasty. J _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Olaf Hering
2011-Sep-22 06:18 UTC
Re: [Xen-devel] [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, Sep 21, stefano.stabellini@eu.citrix.com wrote:> From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > The xen-platform-pci module is small and for PV on HVM guests is a > requirement for xenbus. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>Because it depends on XEN_PVHVM and XEN_PVHVM usage depends on XEN_PLATFORM_PCI: Acked-by: Olaf Hering <olaf@aepfle.de> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ian Campbell
2011-Sep-22 06:21 UTC
Re: [Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, 2011-09-21 at 23:49 +0100, Jeremy Fitzhardinge wrote:> > That would work too. Even better would be to make it an invisible > > Kconfig symbol which PVHVM just selects. > > Eh, select is pretty nasty.Select of a non user visible symbol is perfectly fine. It''s only when you select something a user can also set that things get nasty. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Stefano Stabellini
2011-Sep-22 11:23 UTC
[Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On Wed, 21 Sep 2011, Konrad Rzeszutek Wilk wrote:> On Wed, Sep 21, 2011 at 08:08:15PM +0100, Ian Campbell wrote: > > On Wed, 2011-09-21 at 19:51 +0100, Konrad Rzeszutek Wilk wrote: > > > On Wed, Sep 21, 2011 at 01:37:50PM +0100, stefano.stabellini@eu.citrix.com wrote: > > > > From: Stefano Stabellini <stefano.stabellini@eu.citrix.com> > > > > > > > > The xen-platform-pci module is small and for PV on HVM guests is a > > > > > > How small? > > > > IIRC it is single digit numbers of kb. > > > > > Does it get removed from memory if it never gets loaded? > > > > > > > requirement for xenbus. > > > > > > Ok, should it then have a depency on XenBus as well? > > > > xenbus can''t be a module (which is why allowing platform-pci to be is > > causing problems). > > > > > Linus does not like the ''default y'' very much. He actually dislikes > > > it quite much as I found when he tore Dan''s behind about cleancache. > > > > In particular case the option is gated on a dependency on another Xen > > option (PVHVM) which doesn''t default on. But if you do select PVHVM you > > certainly want this option, so I think that''s ok (why else would > > ''default y'' even exist?) > > > > > .. so I think making it ''default n'' is a better option or perhaps > > > making it depend on some other functionality? Or perhaps just remove > > > the tristate/bool altogether so it gets activated if XEN_PVHVM > > > is set? > > > > > > Or remove the XEN_PLATFORM_PCI config option completly and make the > > > config files that build this driver be CONFIG_XENPVHM dependent? > > > > That would work too. Even better would be to make it an invisible > > Kconfig symbol which PVHVM just selects. > <nods> > Or that since you can''t really do PVHVM without the platform PCI driver. >Considering that we all agree that XEN_PLATFORM_PCI is needed for PVHVM, why should we keep around the old XEN_PLATFORM_PCI config option? I think that Konrad''s idea of just using CONFIG_XEN_PVHVM to build xen-platform-pci.o is the best one. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jeremy Fitzhardinge
2011-Sep-22 19:35 UTC
Re: [Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
On 09/21/2011 11:21 PM, Ian Campbell wrote:> On Wed, 2011-09-21 at 23:49 +0100, Jeremy Fitzhardinge wrote: >>> That would work too. Even better would be to make it an invisible >>> Kconfig symbol which PVHVM just selects. >> Eh, select is pretty nasty. > Select of a non user visible symbol is perfectly fine. It''s only when > you select something a user can also set that things get nasty.It doesn''t matter if its user-visible. If the selected symbol acquires other dependencies, the selection won''t set them. J _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jan Beulich
2011-Sep-23 06:56 UTC
Re: [Xen-devel] Re: [PATCH] xen: change XEN_PLATFORM_PCI to bool default y
>>> On 22.09.11 at 21:35, Jeremy Fitzhardinge <jeremy@goop.org> wrote: > On 09/21/2011 11:21 PM, Ian Campbell wrote: >> On Wed, 2011-09-21 at 23:49 +0100, Jeremy Fitzhardinge wrote: >>>> That would work too. Even better would be to make it an invisible >>>> Kconfig symbol which PVHVM just selects. >>> Eh, select is pretty nasty. >> Select of a non user visible symbol is perfectly fine. It''s only when >> you select something a user can also set that things get nasty. > > It doesn''t matter if its user-visible. If the selected symbol acquires > other dependencies, the selection won''t set them.Despite there being numerous contrary examples in the tree: Either one wants a select-only symbol (then putting dependencies on it is wrong) or one wants an automatic symbol (then selecting it is very likely wrong). Which all boils down to the bogus mixing of normal (forward) and reverse dependencies (using the kconfig source/doc wording). Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel