| Message ID | 20190116175804.30196-6-keith.busch@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Heterogeneuos memory node attributes | expand |
On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > Add entries for memory initiator and target node class attributes. > > Signed-off-by: Keith Busch <keith.busch@intel.com> I would recommend combining this with the previous patch, as the way it is now I need to look at two patches at the time. :-) > --- > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > --- a/Documentation/ABI/stable/sysfs-devices-node > +++ b/Documentation/ABI/stable/sysfs-devices-node > @@ -90,4 +90,27 @@ Date: December 2009 > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > Description: > The node's huge page size control/query attributes. > - See Documentation/admin-guide/mm/hugetlbpage.rst > \ No newline at end of file > + See Documentation/admin-guide/mm/hugetlbpage.rst > + > +What: /sys/devices/system/node/nodeX/classY/ > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node's relationship to other nodes for access class "Y". > + > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node list of memory initiators that have class "Y" access > + to this node's memory. CPUs and other memory initiators in > + nodes not in the list accessing this node's memory may have > + different performance. This does not follow the general "one value per file" rule of sysfs (I know that there are other sysfs files with more than one value in them, but it is better to follow this rule as long as that makes sense). > + > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node list of memory targets that this initiator node has > + class "Y" access. Memory accesses from this node to nodes not > + in this list may have differet performance. > -- Same here. And if you follow the recommendation given in the previous message (add "initiators" and "targets" subdirs under "classX"), you won't even need the two files above. And, of course, the symlinks part needs to be documented as well. I guess you can follow the Documentation/ABI/testing/sysfs-devices-power_resources_D0 with that.
On Wed, 16 Jan 2019 10:57:56 -0700 Keith Busch <keith.busch@intel.com> wrote: > Add entries for memory initiator and target node class attributes. > > Signed-off-by: Keith Busch <keith.busch@intel.com> > --- > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > --- a/Documentation/ABI/stable/sysfs-devices-node > +++ b/Documentation/ABI/stable/sysfs-devices-node > @@ -90,4 +90,27 @@ Date: December 2009 > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > Description: > The node's huge page size control/query attributes. > - See Documentation/admin-guide/mm/hugetlbpage.rst > \ No newline at end of file > + See Documentation/admin-guide/mm/hugetlbpage.rst > + > +What: /sys/devices/system/node/nodeX/classY/ > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node's relationship to other nodes for access class "Y". > + > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node list of memory initiators that have class "Y" access > + to this node's memory. CPUs and other memory initiators in > + nodes not in the list accessing this node's memory may have > + different performance. > + > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > +Date: December 2018 > +Contact: Keith Busch <keith.busch@intel.com> > +Description: > + The node list of memory targets that this initiator node has > + class "Y" access. Memory accesses from this node to nodes not > + in this list may have differet performance. Different performance from what? In the other thread we established that these target_nodelists are kind of a backwards reference, they all have their characteristics anyway. Perhaps this just needs to say: "Memory access from this node to these targets may have different performance"? i.e. Don't make the assumption I did that they should all be the same!
On Fri, Jan 18, 2019 at 3:22 AM Jonathan Cameron <jonathan.cameron@huawei.com> wrote: > > On Wed, 16 Jan 2019 10:57:56 -0700 > Keith Busch <keith.busch@intel.com> wrote: > > > Add entries for memory initiator and target node class attributes. > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > --- > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > --- a/Documentation/ABI/stable/sysfs-devices-node > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > @@ -90,4 +90,27 @@ Date: December 2009 > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > Description: > > The node's huge page size control/query attributes. > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > \ No newline at end of file > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > + > > +What: /sys/devices/system/node/nodeX/classY/ > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node's relationship to other nodes for access class "Y". > > + > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory initiators that have class "Y" access > > + to this node's memory. CPUs and other memory initiators in > > + nodes not in the list accessing this node's memory may have > > + different performance. > > + > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory targets that this initiator node has > > + class "Y" access. Memory accesses from this node to nodes not > > + in this list may have differet performance. > > Different performance from what? In the other thread we established that > these target_nodelists are kind of a backwards reference, they all have > their characteristics anyway. Perhaps this just needs to say: > "Memory access from this node to these targets may have different performance"? > > i.e. Don't make the assumption I did that they should all be the same! I think a clarification of "class" is needed in this context. A "class" is the the set of initiators that have the same rated performance to a given target set. In other words "class" is a tuple of (performance profile, initiator set, target set). Different performance creates a different tuple / class.
On Thu, Jan 17, 2019 at 12:41:19PM +0100, Rafael J. Wysocki wrote: > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > Add entries for memory initiator and target node class attributes. > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > I would recommend combining this with the previous patch, as the way > it is now I need to look at two patches at the time. :-) Will do. > > --- > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > --- a/Documentation/ABI/stable/sysfs-devices-node > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > @@ -90,4 +90,27 @@ Date: December 2009 > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > Description: > > The node's huge page size control/query attributes. > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > \ No newline at end of file > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > + > > +What: /sys/devices/system/node/nodeX/classY/ > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node's relationship to other nodes for access class "Y". > > + > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory initiators that have class "Y" access > > + to this node's memory. CPUs and other memory initiators in > > + nodes not in the list accessing this node's memory may have > > + different performance. > > This does not follow the general "one value per file" rule of sysfs (I > know that there are other sysfs files with more than one value in > them, but it is better to follow this rule as long as that makes > sense). I think it actually does make sense to use "%*pbl" format here. The type we're displaying is a bit array, so this is one value for that attribute. There are many precedents for disapling bit arrays this way. The existing node attributes that we're appending to show cpu lists, and the top loevel shows node lists for "possible", "online", "has_memory", "has_cpu". This new attribute should fit well with exisiting similar attributes from this subsystem. > > + > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory targets that this initiator node has > > + class "Y" access. Memory accesses from this node to nodes not > > + in this list may have differet performance. > > -- > > Same here. > > And if you follow the recommendation given in the previous message > (add "initiators" and "targets" subdirs under "classX"), you won't > even need the two files above. I think that makes sense, I'll take try out this suggestion. > And, of course, the symlinks part needs to be documented as well. I > guess you can follow the > Documentation/ABI/testing/sysfs-devices-power_resources_D0 with that.
On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > Add entries for memory initiator and target node class attributes. > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > I would recommend combining this with the previous patch, as the way > it is now I need to look at two patches at the time. :-) > > > --- > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > --- a/Documentation/ABI/stable/sysfs-devices-node > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > @@ -90,4 +90,27 @@ Date: December 2009 > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > Description: > > The node's huge page size control/query attributes. > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > \ No newline at end of file > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > + > > +What: /sys/devices/system/node/nodeX/classY/ > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node's relationship to other nodes for access class "Y". > > + > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory initiators that have class "Y" access > > + to this node's memory. CPUs and other memory initiators in > > + nodes not in the list accessing this node's memory may have > > + different performance. > > This does not follow the general "one value per file" rule of sysfs (I > know that there are other sysfs files with more than one value in > them, but it is better to follow this rule as long as that makes > sense). > > > + > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > +Date: December 2018 > > +Contact: Keith Busch <keith.busch@intel.com> > > +Description: > > + The node list of memory targets that this initiator node has > > + class "Y" access. Memory accesses from this node to nodes not > > + in this list may have differet performance. > > -- > > Same here. > > And if you follow the recommendation given in the previous message > (add "initiators" and "targets" subdirs under "classX"), you won't > even need the two files above. This recommendation is in conflict with Greg's feedback about kobject usage. If these are just "vanity" subdirs I think it's better to have a multi-value sysfs file. This "list" style is already commonplace for the /sys/devices/system hierarchy.
On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > I would recommend combining this with the previous patch, as the way > > it is now I need to look at two patches at the time. :-) > > > > > --- > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > Description: > > > The node's huge page size control/query attributes. > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > \ No newline at end of file > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > + > > > +What: /sys/devices/system/node/nodeX/classY/ > > > +Date: December 2018 > > > +Contact: Keith Busch <keith.busch@intel.com> > > > +Description: > > > + The node's relationship to other nodes for access class "Y". > > > + > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > +Date: December 2018 > > > +Contact: Keith Busch <keith.busch@intel.com> > > > +Description: > > > + The node list of memory initiators that have class "Y" access > > > + to this node's memory. CPUs and other memory initiators in > > > + nodes not in the list accessing this node's memory may have > > > + different performance. > > > > This does not follow the general "one value per file" rule of sysfs (I > > know that there are other sysfs files with more than one value in > > them, but it is better to follow this rule as long as that makes > > sense). > > > > > + > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > +Date: December 2018 > > > +Contact: Keith Busch <keith.busch@intel.com> > > > +Description: > > > + The node list of memory targets that this initiator node has > > > + class "Y" access. Memory accesses from this node to nodes not > > > + in this list may have differet performance. > > > -- > > > > Same here. > > > > And if you follow the recommendation given in the previous message > > (add "initiators" and "targets" subdirs under "classX"), you won't > > even need the two files above. > > This recommendation is in conflict with Greg's feedback about kobject > usage. If these are just "vanity" subdirs I think it's better to have > a multi-value sysfs file. This "list" style is already commonplace for > the /sys/devices/system hierarchy. If you do a subdirectory "correctly" (i.e. a name for an attribute group), that's fine. Just do not ever create a kobject just for a subdir, that will mess up userspace. And I hate the "multi-value" sysfs files, where at all possible, please do not copy past bad mistakes there. If you can make them individual files, please do that, it makes it easier to maintain and code the kernel for. thanks, greg k-h
On Sat, Jan 19, 2019 at 1:01 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > > > I would recommend combining this with the previous patch, as the way > > > it is now I need to look at two patches at the time. :-) > > > > > > > --- > > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > > Description: > > > > The node's huge page size control/query attributes. > > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > > \ No newline at end of file > > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/ > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node's relationship to other nodes for access class "Y". > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node list of memory initiators that have class "Y" access > > > > + to this node's memory. CPUs and other memory initiators in > > > > + nodes not in the list accessing this node's memory may have > > > > + different performance. > > > > > > This does not follow the general "one value per file" rule of sysfs (I > > > know that there are other sysfs files with more than one value in > > > them, but it is better to follow this rule as long as that makes > > > sense). > > > > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node list of memory targets that this initiator node has > > > > + class "Y" access. Memory accesses from this node to nodes not > > > > + in this list may have differet performance. > > > > -- > > > > > > Same here. > > > > > > And if you follow the recommendation given in the previous message > > > (add "initiators" and "targets" subdirs under "classX"), you won't > > > even need the two files above. > > > > This recommendation is in conflict with Greg's feedback about kobject > > usage. If these are just "vanity" subdirs I think it's better to have > > a multi-value sysfs file. This "list" style is already commonplace for > > the /sys/devices/system hierarchy. > > If you do a subdirectory "correctly" (i.e. a name for an attribute > group), that's fine. Just do not ever create a kobject just for a > subdir, that will mess up userspace. > > And I hate the "multi-value" sysfs files, where at all possible, please > do not copy past bad mistakes there. If you can make them individual > files, please do that, it makes it easier to maintain and code the > kernel for. I agree in general about multi-value sysfs, but in this case we're talking about a mask. Masks are a single value. That said I can get on board with calling what 'cpulist' does a design mistake (human readable mask), but otherwise switching to one file per item in the mask is a mess for userspace to consume.
On Sat, Jan 19, 2019 at 10:01 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > > > I would recommend combining this with the previous patch, as the way > > > it is now I need to look at two patches at the time. :-) > > > > > > > --- > > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > > Description: > > > > The node's huge page size control/query attributes. > > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > > \ No newline at end of file > > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/ > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node's relationship to other nodes for access class "Y". > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node list of memory initiators that have class "Y" access > > > > + to this node's memory. CPUs and other memory initiators in > > > > + nodes not in the list accessing this node's memory may have > > > > + different performance. > > > > > > This does not follow the general "one value per file" rule of sysfs (I > > > know that there are other sysfs files with more than one value in > > > them, but it is better to follow this rule as long as that makes > > > sense). > > > > > > > + > > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > > +Date: December 2018 > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > +Description: > > > > + The node list of memory targets that this initiator node has > > > > + class "Y" access. Memory accesses from this node to nodes not > > > > + in this list may have differet performance. > > > > -- > > > > > > Same here. > > > > > > And if you follow the recommendation given in the previous message > > > (add "initiators" and "targets" subdirs under "classX"), you won't > > > even need the two files above. > > > > This recommendation is in conflict with Greg's feedback about kobject > > usage. If these are just "vanity" subdirs I think it's better to have > > a multi-value sysfs file. This "list" style is already commonplace for > > the /sys/devices/system hierarchy. > > If you do a subdirectory "correctly" (i.e. a name for an attribute > group), that's fine. Yes, that's what I was thinking about: along the lines of the "power" group under device kobjects. Cheers, Rafael
On Sat, Jan 19, 2019 at 5:56 PM Dan Williams <dan.j.williams@intel.com> wrote: > > On Sat, Jan 19, 2019 at 1:01 AM Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > > > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > > > > > I would recommend combining this with the previous patch, as the way > > > > it is now I need to look at two patches at the time. :-) > > > > > > > > > --- > > > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > > > Description: > > > > > The node's huge page size control/query attributes. > > > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > \ No newline at end of file > > > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > + > > > > > +What: /sys/devices/system/node/nodeX/classY/ > > > > > +Date: December 2018 > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > +Description: > > > > > + The node's relationship to other nodes for access class "Y". > > > > > + > > > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > > > +Date: December 2018 > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > +Description: > > > > > + The node list of memory initiators that have class "Y" access > > > > > + to this node's memory. CPUs and other memory initiators in > > > > > + nodes not in the list accessing this node's memory may have > > > > > + different performance. > > > > > > > > This does not follow the general "one value per file" rule of sysfs (I > > > > know that there are other sysfs files with more than one value in > > > > them, but it is better to follow this rule as long as that makes > > > > sense). > > > > > > > > > + > > > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > > > +Date: December 2018 > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > +Description: > > > > > + The node list of memory targets that this initiator node has > > > > > + class "Y" access. Memory accesses from this node to nodes not > > > > > + in this list may have differet performance. > > > > > -- > > > > > > > > Same here. > > > > > > > > And if you follow the recommendation given in the previous message > > > > (add "initiators" and "targets" subdirs under "classX"), you won't > > > > even need the two files above. > > > > > > This recommendation is in conflict with Greg's feedback about kobject > > > usage. If these are just "vanity" subdirs I think it's better to have > > > a multi-value sysfs file. This "list" style is already commonplace for > > > the /sys/devices/system hierarchy. > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > group), that's fine. Just do not ever create a kobject just for a > > subdir, that will mess up userspace. > > > > And I hate the "multi-value" sysfs files, where at all possible, please > > do not copy past bad mistakes there. If you can make them individual > > files, please do that, it makes it easier to maintain and code the > > kernel for. > > I agree in general about multi-value sysfs, but in this case we're > talking about a mask. Masks are a single value. That said I can get on > board with calling what 'cpulist' does a design mistake (human > readable mask), but otherwise switching to one file per item in the > mask is a mess for userspace to consume. Can you please refer to my response to Keith? If you have "initiators" and "targets" under "classX" and a list of symlinks in each of them, I don't see any kind of a mess here.
On Sun, Jan 20, 2019 at 8:20 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Sat, Jan 19, 2019 at 5:56 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > On Sat, Jan 19, 2019 at 1:01 AM Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > > > > > > On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > > > > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > > > > > > > I would recommend combining this with the previous patch, as the way > > > > > it is now I need to look at two patches at the time. :-) > > > > > > > > > > > --- > > > > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > > > > Description: > > > > > > The node's huge page size control/query attributes. > > > > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > > \ No newline at end of file > > > > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > > + > > > > > > +What: /sys/devices/system/node/nodeX/classY/ > > > > > > +Date: December 2018 > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > +Description: > > > > > > + The node's relationship to other nodes for access class "Y". > > > > > > + > > > > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > > > > +Date: December 2018 > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > +Description: > > > > > > + The node list of memory initiators that have class "Y" access > > > > > > + to this node's memory. CPUs and other memory initiators in > > > > > > + nodes not in the list accessing this node's memory may have > > > > > > + different performance. > > > > > > > > > > This does not follow the general "one value per file" rule of sysfs (I > > > > > know that there are other sysfs files with more than one value in > > > > > them, but it is better to follow this rule as long as that makes > > > > > sense). > > > > > > > > > > > + > > > > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > > > > +Date: December 2018 > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > +Description: > > > > > > + The node list of memory targets that this initiator node has > > > > > > + class "Y" access. Memory accesses from this node to nodes not > > > > > > + in this list may have differet performance. > > > > > > -- > > > > > > > > > > Same here. > > > > > > > > > > And if you follow the recommendation given in the previous message > > > > > (add "initiators" and "targets" subdirs under "classX"), you won't > > > > > even need the two files above. > > > > > > > > This recommendation is in conflict with Greg's feedback about kobject > > > > usage. If these are just "vanity" subdirs I think it's better to have > > > > a multi-value sysfs file. This "list" style is already commonplace for > > > > the /sys/devices/system hierarchy. > > > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > > group), that's fine. Just do not ever create a kobject just for a > > > subdir, that will mess up userspace. > > > > > > And I hate the "multi-value" sysfs files, where at all possible, please > > > do not copy past bad mistakes there. If you can make them individual > > > files, please do that, it makes it easier to maintain and code the > > > kernel for. > > > > I agree in general about multi-value sysfs, but in this case we're > > talking about a mask. Masks are a single value. That said I can get on > > board with calling what 'cpulist' does a design mistake (human > > readable mask), but otherwise switching to one file per item in the > > mask is a mess for userspace to consume. > > Can you please refer to my response to Keith? Ah, ok I missed the patch4 comments and was reading this one in isolation... which also bolsters your comment about squashing these two patches together. > If you have "initiators" and "targets" under "classX" and a list of > symlinks in each of them, I don't see any kind of a mess here. In this instance, I think having symlinks at all is "messy" vs just having a mask. Yes, you're right, if we have the proposed symlinks from patch4 there is no need for these _nodelist attributes, and those symlinks would be better under "initiator" and "target" directories. However, I'm arguing going the other way, just have the 2 mask attributes and no symlinks. The HMAT erodes the concept of "numa nodes" typically being a single digit number space per platform. Given increasing numbers of memory target types and initiator devices its going to be cumbersome to have userspace walk multiple symlinks vs just reading a mask and opening the canonical path for a node directly. This is also part of the rationale for only emitting one "class" (initiator / target performance profile) by default. There's an N-to-N initiator-target description in the HMAT. When / if we decide emit more classes the more work userspace would need to do to convert directory structures back into data.
On Sun, Jan 20, 2019 at 6:34 PM Dan Williams <dan.j.williams@intel.com> wrote: > > On Sun, Jan 20, 2019 at 8:20 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > On Sat, Jan 19, 2019 at 5:56 PM Dan Williams <dan.j.williams@intel.com> wrote: > > > > > > On Sat, Jan 19, 2019 at 1:01 AM Greg Kroah-Hartman > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > On Fri, Jan 18, 2019 at 01:08:02PM -0800, Dan Williams wrote: > > > > > On Thu, Jan 17, 2019 at 3:41 AM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > > > > > > > > > On Wed, Jan 16, 2019 at 6:59 PM Keith Busch <keith.busch@intel.com> wrote: > > > > > > > > > > > > > > Add entries for memory initiator and target node class attributes. > > > > > > > > > > > > > > Signed-off-by: Keith Busch <keith.busch@intel.com> > > > > > > > > > > > > I would recommend combining this with the previous patch, as the way > > > > > > it is now I need to look at two patches at the time. :-) > > > > > > > > > > > > > --- > > > > > > > Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- > > > > > > > 1 file changed, 24 insertions(+), 1 deletion(-) > > > > > > > > > > > > > > diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node > > > > > > > index 3e90e1f3bf0a..a9c47b4b0eee 100644 > > > > > > > --- a/Documentation/ABI/stable/sysfs-devices-node > > > > > > > +++ b/Documentation/ABI/stable/sysfs-devices-node > > > > > > > @@ -90,4 +90,27 @@ Date: December 2009 > > > > > > > Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> > > > > > > > Description: > > > > > > > The node's huge page size control/query attributes. > > > > > > > - See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > > > \ No newline at end of file > > > > > > > + See Documentation/admin-guide/mm/hugetlbpage.rst > > > > > > > + > > > > > > > +What: /sys/devices/system/node/nodeX/classY/ > > > > > > > +Date: December 2018 > > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > > +Description: > > > > > > > + The node's relationship to other nodes for access class "Y". > > > > > > > + > > > > > > > +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist > > > > > > > +Date: December 2018 > > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > > +Description: > > > > > > > + The node list of memory initiators that have class "Y" access > > > > > > > + to this node's memory. CPUs and other memory initiators in > > > > > > > + nodes not in the list accessing this node's memory may have > > > > > > > + different performance. > > > > > > > > > > > > This does not follow the general "one value per file" rule of sysfs (I > > > > > > know that there are other sysfs files with more than one value in > > > > > > them, but it is better to follow this rule as long as that makes > > > > > > sense). > > > > > > > > > > > > > + > > > > > > > +What: /sys/devices/system/node/nodeX/classY/target_nodelist > > > > > > > +Date: December 2018 > > > > > > > +Contact: Keith Busch <keith.busch@intel.com> > > > > > > > +Description: > > > > > > > + The node list of memory targets that this initiator node has > > > > > > > + class "Y" access. Memory accesses from this node to nodes not > > > > > > > + in this list may have differet performance. > > > > > > > -- > > > > > > > > > > > > Same here. > > > > > > > > > > > > And if you follow the recommendation given in the previous message > > > > > > (add "initiators" and "targets" subdirs under "classX"), you won't > > > > > > even need the two files above. > > > > > > > > > > This recommendation is in conflict with Greg's feedback about kobject > > > > > usage. If these are just "vanity" subdirs I think it's better to have > > > > > a multi-value sysfs file. This "list" style is already commonplace for > > > > > the /sys/devices/system hierarchy. > > > > > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > > > group), that's fine. Just do not ever create a kobject just for a > > > > subdir, that will mess up userspace. > > > > > > > > And I hate the "multi-value" sysfs files, where at all possible, please > > > > do not copy past bad mistakes there. If you can make them individual > > > > files, please do that, it makes it easier to maintain and code the > > > > kernel for. > > > > > > I agree in general about multi-value sysfs, but in this case we're > > > talking about a mask. Masks are a single value. That said I can get on > > > board with calling what 'cpulist' does a design mistake (human > > > readable mask), but otherwise switching to one file per item in the > > > mask is a mess for userspace to consume. > > > > Can you please refer to my response to Keith? > > Ah, ok I missed the patch4 comments and was reading this one in > isolation... which also bolsters your comment about squashing these > two patches together. > > > If you have "initiators" and "targets" under "classX" and a list of > > symlinks in each of them, I don't see any kind of a mess here. > > In this instance, I think having symlinks at all is "messy" vs just > having a mask. Yes, you're right, if we have the proposed symlinks > from patch4 there is no need for these _nodelist attributes, and those > symlinks would be better under "initiator" and "target" directories. > However, I'm arguing going the other way, just have the 2 mask > attributes and no symlinks. The HMAT erodes the concept of "numa > nodes" typically being a single digit number space per platform. Given > increasing numbers of memory target types and initiator devices its > going to be cumbersome to have userspace walk multiple symlinks vs > just reading a mask and opening the canonical path for a node > directly. The symlinks only need to be walked once, however, and after walking them (once) the user space program can simply create a mask for itself. To me, the question here is how to represent a graph in a filesystem, and since nodes are naturally represented by directories, it is also natural to represent connections between them as symlinks. > This is also part of the rationale for only emitting one "class" > (initiator / target performance profile) by default. There's an N-to-N > initiator-target description in the HMAT. When / if we decide emit > more classes the more work userspace would need to do to convert > directory structures back into data. I'm not convinced by this argument, as this conversion is a one-off exercise. Ultimately, a tool in user space would need to represent a graph anyway and how it obtains the data to do that doesn't matter too much to it. However, IMO there is value in representing the graph in a filesystem in such a way that, say, a file manager program (without special modifications) can be used to walk it by a human. Let alone the one-value-per-file rule of sysfs that doesn't need to be violated if symlinks are used.
On Sun, Jan 20, 2019 at 05:16:05PM +0100, Rafael J. Wysocki wrote: > On Sat, Jan 19, 2019 at 10:01 AM Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > group), that's fine. > > Yes, that's what I was thinking about: along the lines of the "power" > group under device kobjects. We can't append symlinks to an attribute group, though. I'd need to create a lot of struct devices just to get the desired directory hiearchy. And then each of those "devices" will have their own "power" group, which really doesn't make any sense for what we're trying to show. Is that really the right way to do this, or something else I'm missing?
On Tue, Jan 22, 2019 at 5:37 PM Keith Busch <keith.busch@intel.com> wrote: > > On Sun, Jan 20, 2019 at 05:16:05PM +0100, Rafael J. Wysocki wrote: > > On Sat, Jan 19, 2019 at 10:01 AM Greg Kroah-Hartman > > <gregkh@linuxfoundation.org> wrote: > > > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > > group), that's fine. > > > > Yes, that's what I was thinking about: along the lines of the "power" > > group under device kobjects. > > We can't append symlinks to an attribute group, though. That's right, unfortunately. > I'd need to create a lot of struct devices just to get the desired directory hiearchy. No, you don't need to do that. Kobjects can be added without registering a struct device for each of them kind of along the lines of what cpufreq does for its policy objects etc. See cpufreq_policy_alloc() and cpufreq_core_init() for examples. > And then each of those "devices" will have their own "power" group, which > really doesn't make any sense for what we're trying to show. Is that > really the right way to do this, or something else I'm missing? Above?
On Tue, Jan 22, 2019 at 5:51 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > On Tue, Jan 22, 2019 at 5:37 PM Keith Busch <keith.busch@intel.com> wrote: > > > > On Sun, Jan 20, 2019 at 05:16:05PM +0100, Rafael J. Wysocki wrote: > > > On Sat, Jan 19, 2019 at 10:01 AM Greg Kroah-Hartman > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > If you do a subdirectory "correctly" (i.e. a name for an attribute > > > > group), that's fine. > > > > > > Yes, that's what I was thinking about: along the lines of the "power" > > > group under device kobjects. > > > > We can't append symlinks to an attribute group, though. > > That's right, unfortunately. Scratch this. You can add them using sysfs_add_link_to_group(). For example, see what acpi_power_expose_list() does.
diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node index 3e90e1f3bf0a..a9c47b4b0eee 100644 --- a/Documentation/ABI/stable/sysfs-devices-node +++ b/Documentation/ABI/stable/sysfs-devices-node @@ -90,4 +90,27 @@ Date: December 2009 Contact: Lee Schermerhorn <lee.schermerhorn@hp.com> Description: The node's huge page size control/query attributes. - See Documentation/admin-guide/mm/hugetlbpage.rst \ No newline at end of file + See Documentation/admin-guide/mm/hugetlbpage.rst + +What: /sys/devices/system/node/nodeX/classY/ +Date: December 2018 +Contact: Keith Busch <keith.busch@intel.com> +Description: + The node's relationship to other nodes for access class "Y". + +What: /sys/devices/system/node/nodeX/classY/initiator_nodelist +Date: December 2018 +Contact: Keith Busch <keith.busch@intel.com> +Description: + The node list of memory initiators that have class "Y" access + to this node's memory. CPUs and other memory initiators in + nodes not in the list accessing this node's memory may have + different performance. + +What: /sys/devices/system/node/nodeX/classY/target_nodelist +Date: December 2018 +Contact: Keith Busch <keith.busch@intel.com> +Description: + The node list of memory targets that this initiator node has + class "Y" access. Memory accesses from this node to nodes not + in this list may have differet performance.
Add entries for memory initiator and target node class attributes. Signed-off-by: Keith Busch <keith.busch@intel.com> --- Documentation/ABI/stable/sysfs-devices-node | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-)