Danilo Krummrich
2023-Oct-31 17:52 UTC
[Nouveau] [PATCH drm-misc-next v7 4/7] drm/gpuvm: add an abstraction for a VM / BO combination
On 10/31/23 17:45, Thomas Hellstr?m wrote:> On Tue, 2023-10-31 at 17:39 +0100, Danilo Krummrich wrote: >> On 10/31/23 12:25, Thomas Hellstr?m wrote: >>> On Mon, 2023-10-23 at 22:16 +0200, Danilo Krummrich wrote: >>>> Add an abstraction layer between the drm_gpuva mappings of a >>>> particular >>>> drm_gem_object and this GEM object itself. The abstraction >>>> represents >>>> a >>>> combination of a drm_gem_object and drm_gpuvm. The drm_gem_object >>>> holds >>>> a list of drm_gpuvm_bo structures (the structure representing >>>> this >>>> abstraction), while each drm_gpuvm_bo contains list of mappings >>>> of >>>> this >>>> GEM object. >>>> >>>> This has multiple advantages: >>>> >>>> 1) We can use the drm_gpuvm_bo structure to attach it to various >>>> lists >>>> ??? of the drm_gpuvm. This is useful for tracking external and >>>> evicted >>>> ??? objects per VM, which is introduced in subsequent patches. >>>> >>>> 2) Finding mappings of a certain drm_gem_object mapped in a >>>> certain >>>> ??? drm_gpuvm becomes much cheaper. >>>> >>>> 3) Drivers can derive and extend the structure to easily >>>> represent >>>> ??? driver specific states of a BO for a certain GPUVM. >>>> >>>> The idea of this abstraction was taken from amdgpu, hence the >>>> credit >>>> for >>>> this idea goes to the developers of amdgpu. >>>> >>>> Cc: Christian K?nig <christian.koenig at amd.com> >>>> Signed-off-by: Danilo Krummrich <dakr at redhat.com> >>>> --- >>>> ??drivers/gpu/drm/drm_gpuvm.c??????????? | 335 >>>> +++++++++++++++++++++-- >>>> -- >>>> ??drivers/gpu/drm/nouveau/nouveau_uvmm.c |? 64 +++-- >>>> ??include/drm/drm_gem.h????????????????? |? 32 +-- >>>> ??include/drm/drm_gpuvm.h??????????????? | 188 +++++++++++++- >>>> ??4 files changed, 533 insertions(+), 86 deletions(-) >>> >>> That checkpatch.pl error still remains as well. >> >> I guess you refer to: >> >> ERROR: do not use assignment in if condition >> #633: FILE: drivers/gpu/drm/nouveau/nouveau_uvmm.c:1165: >> +?????????????????????? if (!(op->gem.obj = obj)) >> >> This was an intentional decision, since in this specific case it >> seems to >> be more readable than the alternatives. >> >> However, if we consider this to be a hard rule, which we never ever >> break, >> I'm fine changing it too. > > With the errors, sooner or later they are going to start generate > patches to "fix" them. In this particular case also Xe CI is > complaining and abort building when I submit the Xe adaptation, so it'd > be good to be checkpatch.pl conformant IMHO.Ok, I will change this one. However, in general my opinion on coding style is that we should preserve us the privilege to deviate from it when we agree it makes sense and improves the code quality. Having a CI forcing people to *blindly* follow certain rules and even abort building isn't very beneficial in that respect. Also, consider patches which partially change a line of code that already contains a coding style "issue" - the CI would also block you on that one I guess. Besides that it seems to block you on unrelated code, note that the assignment in question is from Nouveau and not from GPUVM. - Danilo> > Thanks, > Thomas > > > > >> >>> >>> Thanks, >>> Thomas >>> >> >
Thomas Hellström
2023-Nov-01 09:41 UTC
[Nouveau] [PATCH drm-misc-next v7 4/7] drm/gpuvm: add an abstraction for a VM / BO combination
Hi, Danilo, On Tue, 2023-10-31 at 18:52 +0100, Danilo Krummrich wrote:> On 10/31/23 17:45, Thomas Hellstr?m wrote: > > On Tue, 2023-10-31 at 17:39 +0100, Danilo Krummrich wrote: > > > On 10/31/23 12:25, Thomas Hellstr?m wrote: > > > > On Mon, 2023-10-23 at 22:16 +0200, Danilo Krummrich wrote: > > > > > Add an abstraction layer between the drm_gpuva mappings of a > > > > > particular > > > > > drm_gem_object and this GEM object itself. The abstraction > > > > > represents > > > > > a > > > > > combination of a drm_gem_object and drm_gpuvm. The > > > > > drm_gem_object > > > > > holds > > > > > a list of drm_gpuvm_bo structures (the structure representing > > > > > this > > > > > abstraction), while each drm_gpuvm_bo contains list of > > > > > mappings > > > > > of > > > > > this > > > > > GEM object. > > > > > > > > > > This has multiple advantages: > > > > > > > > > > 1) We can use the drm_gpuvm_bo structure to attach it to > > > > > various > > > > > lists > > > > > ???? of the drm_gpuvm. This is useful for tracking external > > > > > and > > > > > evicted > > > > > ???? objects per VM, which is introduced in subsequent > > > > > patches. > > > > > > > > > > 2) Finding mappings of a certain drm_gem_object mapped in a > > > > > certain > > > > > ???? drm_gpuvm becomes much cheaper. > > > > > > > > > > 3) Drivers can derive and extend the structure to easily > > > > > represent > > > > > ???? driver specific states of a BO for a certain GPUVM. > > > > > > > > > > The idea of this abstraction was taken from amdgpu, hence the > > > > > credit > > > > > for > > > > > this idea goes to the developers of amdgpu. > > > > > > > > > > Cc: Christian K?nig <christian.koenig at amd.com> > > > > > Signed-off-by: Danilo Krummrich <dakr at redhat.com> > > > > > --- > > > > > ???drivers/gpu/drm/drm_gpuvm.c??????????? | 335 > > > > > +++++++++++++++++++++-- > > > > > -- > > > > > ???drivers/gpu/drm/nouveau/nouveau_uvmm.c |? 64 +++-- > > > > > ???include/drm/drm_gem.h????????????????? |? 32 +-- > > > > > ???include/drm/drm_gpuvm.h??????????????? | 188 > > > > > +++++++++++++- > > > > > ???4 files changed, 533 insertions(+), 86 deletions(-) > > > > > > > > That checkpatch.pl error still remains as well. > > > > > > I guess you refer to: > > > > > > ERROR: do not use assignment in if condition > > > #633: FILE: drivers/gpu/drm/nouveau/nouveau_uvmm.c:1165: > > > +?????????????????????? if (!(op->gem.obj = obj)) > > > > > > This was an intentional decision, since in this specific case it > > > seems to > > > be more readable than the alternatives. > > > > > > However, if we consider this to be a hard rule, which we never > > > ever > > > break, > > > I'm fine changing it too. > > > > With the errors, sooner or later they are going to start generate > > patches to "fix" them. In this particular case also Xe CI is > > complaining and abort building when I submit the Xe adaptation, so > > it'd > > be good to be checkpatch.pl conformant IMHO. > > Ok, I will change this one. > > However, in general my opinion on coding style is that we should > preserve us > the privilege to deviate from it when we agree it makes sense and > improves > the code quality. > > Having a CI forcing people to *blindly* follow certain rules and even > abort > building isn't very beneficial in that respect. > > Also, consider patches which partially change a line of code that > already > contains a coding style "issue" - the CI would also block you on that > one I > guess. Besides that it seems to block you on unrelated code, note > that the > assignment in question is from Nouveau and not from GPUVM.Yes, I completely agree that having CI enforce error free coding style checks is bad, and I'll see if I can get that changed on Xe CI. To my Knowledge It hasn't always been like that. But OTOH my take on this is that if there are coding style rules and recommendations we should try to follow them unless there are *strong* reasons not to. Sometimes that may result in code that may be a little harder to read, but OTOH a reviewer won't have to read up on the component's style flavor before reviewing and it will avoid future style fix patches. Thanks, Thomas> > - Danilo > > > > > Thanks, > > Thomas > > > > > > > > > > > > > > > > > > > Thanks, > > > > Thomas > > > > > > > > > >