| Message ID | 20221116075736.1909690-3-vishal.l.verma@intel.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | ACPI: HMAT: fix single-initiator target registrations | expand |
On Wed, Nov 16, 2022 at 12:57:36AM -0700, Vishal Verma wrote: > In a system with a single initiator node, and one or more memory-only > 'target' nodes, the memory-only node(s) would fail to register their > initiator node correctly. i.e. in sysfs: > > # ls /sys/devices/system/node/node0/access0/targets/ > node0 > > Where as the correct behavior should be: > > # ls /sys/devices/system/node/node0/access0/targets/ > node0 node1 > > This happened because hmat_register_target_initiators() uses list_sort() > to sort the initiator list, but the sort comparision function > (initiator_cmp()) is overloaded to also set the node mask's bits. > > In a system with a single initiator, the list is singular, and list_sort > elides the comparision helper call. Thus the node mask never gets set, > and the subsequent search for the best initiator comes up empty. > > Add a new helper to sort the initiator list, and handle the singular > list corner case by setting the node mask for that explicitly. > > Reported-by: Chris Piper <chris.d.piper@intel.com> > Cc: <stable@vger.kernel.org> > Cc: Rafael J. Wysocki <rafael@kernel.org> > Cc: Liu Shixin <liushixin2@huawei.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > --- > drivers/acpi/numa/hmat.c | 32 ++++++++++++++++++++++++++++++-- > 1 file changed, 30 insertions(+), 2 deletions(-) > > diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > index 144a84f429ed..cd20b0e9cdfa 100644 > --- a/drivers/acpi/numa/hmat.c > +++ b/drivers/acpi/numa/hmat.c > @@ -573,6 +573,30 @@ static int initiator_cmp(void *priv, const struct list_head *a, > return ia->processor_pxm - ib->processor_pxm; > } > > +static int initiators_to_nodemask(unsigned long *p_nodes) > +{ > + /* > + * list_sort doesn't call @cmp (initiator_cmp) for 0 or 1 sized lists. > + * For a single-initiator system with other memory-only nodes, this > + * means an empty p_nodes mask, since that is set by initiator_cmp(). > + * Special case the singular list, and make sure the node mask gets set > + * appropriately. > + */ > + if (list_empty(&initiators)) > + return -ENXIO; > + > + if (list_is_singular(&initiators)) { > + struct memory_initiator *initiator = list_first_entry( > + &initiators, struct memory_initiator, node); > + > + set_bit(initiator->processor_pxm, p_nodes); > + return 0; > + } > + > + list_sort(p_nodes, &initiators, initiator_cmp); > + return 0; > +} > + Hm. I think it indicates that these set_bit()s do not belong to initiator_cmp(). Maybe remove both set_bit() from the compare helper and walk the list separately to initialize the node mask? I think it will be easier to follow.
On Wed, 2022-11-16 at 15:46 +0300, Kirill A. Shutemov wrote: > On Wed, Nov 16, 2022 at 12:57:36AM -0700, Vishal Verma wrote: > > In a system with a single initiator node, and one or more memory-only > > 'target' nodes, the memory-only node(s) would fail to register their > > initiator node correctly. i.e. in sysfs: > > > > # ls /sys/devices/system/node/node0/access0/targets/ > > node0 > > > > Where as the correct behavior should be: > > > > # ls /sys/devices/system/node/node0/access0/targets/ > > node0 node1 > > > > This happened because hmat_register_target_initiators() uses list_sort() > > to sort the initiator list, but the sort comparision function > > (initiator_cmp()) is overloaded to also set the node mask's bits. > > > > In a system with a single initiator, the list is singular, and list_sort > > elides the comparision helper call. Thus the node mask never gets set, > > and the subsequent search for the best initiator comes up empty. > > > > Add a new helper to sort the initiator list, and handle the singular > > list corner case by setting the node mask for that explicitly. > > > > Reported-by: Chris Piper <chris.d.piper@intel.com> > > Cc: <stable@vger.kernel.org> > > Cc: Rafael J. Wysocki <rafael@kernel.org> > > Cc: Liu Shixin <liushixin2@huawei.com> > > Cc: Dan Williams <dan.j.williams@intel.com> > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > --- > > drivers/acpi/numa/hmat.c | 32 ++++++++++++++++++++++++++++++-- > > 1 file changed, 30 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > > index 144a84f429ed..cd20b0e9cdfa 100644 > > --- a/drivers/acpi/numa/hmat.c > > +++ b/drivers/acpi/numa/hmat.c > > @@ -573,6 +573,30 @@ static int initiator_cmp(void *priv, const struct list_head *a, > > return ia->processor_pxm - ib->processor_pxm; > > } > > > > +static int initiators_to_nodemask(unsigned long *p_nodes) > > +{ > > + /* > > + * list_sort doesn't call @cmp (initiator_cmp) for 0 or 1 sized lists. > > + * For a single-initiator system with other memory-only nodes, this > > + * means an empty p_nodes mask, since that is set by initiator_cmp(). > > + * Special case the singular list, and make sure the node mask gets set > > + * appropriately. > > + */ > > + if (list_empty(&initiators)) > > + return -ENXIO; > > + > > + if (list_is_singular(&initiators)) { > > + struct memory_initiator *initiator = list_first_entry( > > + &initiators, struct memory_initiator, node); > > + > > + set_bit(initiator->processor_pxm, p_nodes); > > + return 0; > > + } > > + > > + list_sort(p_nodes, &initiators, initiator_cmp); > > + return 0; > > +} > > + > > Hm. I think it indicates that these set_bit()s do not belong to > initiator_cmp(). > > Maybe remove both set_bit() from the compare helper and walk the list > separately to initialize the node mask? I think it will be easier to > follow. Yes - I thuoght about this, but went with the seemingly less intrusive change. I can send a v2 which separates out the set_bit()s. I agree that's cleaner and easier to follow than overloading initiator_cmp().
On Wed, Nov 16, 2022 at 06:02:32PM +0000, Verma, Vishal L wrote: > On Wed, 2022-11-16 at 15:46 +0300, Kirill A. Shutemov wrote: > > On Wed, Nov 16, 2022 at 12:57:36AM -0700, Vishal Verma wrote: > > > In a system with a single initiator node, and one or more memory-only > > > 'target' nodes, the memory-only node(s) would fail to register their > > > initiator node correctly. i.e. in sysfs: > > > > > > # ls /sys/devices/system/node/node0/access0/targets/ > > > node0 > > > > > > Where as the correct behavior should be: > > > > > > # ls /sys/devices/system/node/node0/access0/targets/ > > > node0 node1 > > > > > > This happened because hmat_register_target_initiators() uses list_sort() > > > to sort the initiator list, but the sort comparision function > > > (initiator_cmp()) is overloaded to also set the node mask's bits. > > > > > > In a system with a single initiator, the list is singular, and list_sort > > > elides the comparision helper call. Thus the node mask never gets set, > > > and the subsequent search for the best initiator comes up empty. > > > > > > Add a new helper to sort the initiator list, and handle the singular > > > list corner case by setting the node mask for that explicitly. > > > > > > Reported-by: Chris Piper <chris.d.piper@intel.com> > > > Cc: <stable@vger.kernel.org> > > > Cc: Rafael J. Wysocki <rafael@kernel.org> > > > Cc: Liu Shixin <liushixin2@huawei.com> > > > Cc: Dan Williams <dan.j.williams@intel.com> > > > Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> > > > --- > > > drivers/acpi/numa/hmat.c | 32 ++++++++++++++++++++++++++++++-- > > > 1 file changed, 30 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c > > > index 144a84f429ed..cd20b0e9cdfa 100644 > > > --- a/drivers/acpi/numa/hmat.c > > > +++ b/drivers/acpi/numa/hmat.c > > > @@ -573,6 +573,30 @@ static int initiator_cmp(void *priv, const struct list_head *a, > > > return ia->processor_pxm - ib->processor_pxm; > > > } > > > > > > +static int initiators_to_nodemask(unsigned long *p_nodes) > > > +{ > > > + /* > > > + * list_sort doesn't call @cmp (initiator_cmp) for 0 or 1 sized lists. > > > + * For a single-initiator system with other memory-only nodes, this > > > + * means an empty p_nodes mask, since that is set by initiator_cmp(). > > > + * Special case the singular list, and make sure the node mask gets set > > > + * appropriately. > > > + */ > > > + if (list_empty(&initiators)) > > > + return -ENXIO; > > > + > > > + if (list_is_singular(&initiators)) { > > > + struct memory_initiator *initiator = list_first_entry( > > > + &initiators, struct memory_initiator, node); > > > + > > > + set_bit(initiator->processor_pxm, p_nodes); > > > + return 0; > > > + } > > > + > > > + list_sort(p_nodes, &initiators, initiator_cmp); > > > + return 0; > > > +} > > > + > > > > Hm. I think it indicates that these set_bit()s do not belong to > > initiator_cmp(). > > > > Maybe remove both set_bit() from the compare helper and walk the list > > separately to initialize the node mask? I think it will be easier to > > follow. > > > Yes - I thuoght about this, but went with the seemingly less intrusive > change. I can send a v2 which separates out the set_bit()s. I agree > that's cleaner and easier to follow than overloading initiator_cmp(). Yes, please make v2. With current implementation set_bit() can be called multiple times on the same initiator, depending on placement of the initiator in the list. It is totally wrong place.
diff --git a/drivers/acpi/numa/hmat.c b/drivers/acpi/numa/hmat.c index 144a84f429ed..cd20b0e9cdfa 100644 --- a/drivers/acpi/numa/hmat.c +++ b/drivers/acpi/numa/hmat.c @@ -573,6 +573,30 @@ static int initiator_cmp(void *priv, const struct list_head *a, return ia->processor_pxm - ib->processor_pxm; } +static int initiators_to_nodemask(unsigned long *p_nodes) +{ + /* + * list_sort doesn't call @cmp (initiator_cmp) for 0 or 1 sized lists. + * For a single-initiator system with other memory-only nodes, this + * means an empty p_nodes mask, since that is set by initiator_cmp(). + * Special case the singular list, and make sure the node mask gets set + * appropriately. + */ + if (list_empty(&initiators)) + return -ENXIO; + + if (list_is_singular(&initiators)) { + struct memory_initiator *initiator = list_first_entry( + &initiators, struct memory_initiator, node); + + set_bit(initiator->processor_pxm, p_nodes); + return 0; + } + + list_sort(p_nodes, &initiators, initiator_cmp); + return 0; +} + static void hmat_register_target_initiators(struct memory_target *target) { static DECLARE_BITMAP(p_nodes, MAX_NUMNODES); @@ -609,7 +633,9 @@ static void hmat_register_target_initiators(struct memory_target *target) * initiators. */ bitmap_zero(p_nodes, MAX_NUMNODES); - list_sort(p_nodes, &initiators, initiator_cmp); + if (initiators_to_nodemask(p_nodes) < 0) + return; + if (!access0done) { for (i = WRITE_LATENCY; i <= READ_BANDWIDTH; i++) { loc = localities_types[i]; @@ -643,7 +669,9 @@ static void hmat_register_target_initiators(struct memory_target *target) /* Access 1 ignores Generic Initiators */ bitmap_zero(p_nodes, MAX_NUMNODES); - list_sort(p_nodes, &initiators, initiator_cmp); + if (initiators_to_nodemask(p_nodes) < 0) + return; + for (i = WRITE_LATENCY; i <= READ_BANDWIDTH; i++) { loc = localities_types[i]; if (!loc)
In a system with a single initiator node, and one or more memory-only 'target' nodes, the memory-only node(s) would fail to register their initiator node correctly. i.e. in sysfs: # ls /sys/devices/system/node/node0/access0/targets/ node0 Where as the correct behavior should be: # ls /sys/devices/system/node/node0/access0/targets/ node0 node1 This happened because hmat_register_target_initiators() uses list_sort() to sort the initiator list, but the sort comparision function (initiator_cmp()) is overloaded to also set the node mask's bits. In a system with a single initiator, the list is singular, and list_sort elides the comparision helper call. Thus the node mask never gets set, and the subsequent search for the best initiator comes up empty. Add a new helper to sort the initiator list, and handle the singular list corner case by setting the node mask for that explicitly. Reported-by: Chris Piper <chris.d.piper@intel.com> Cc: <stable@vger.kernel.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Liu Shixin <liushixin2@huawei.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> --- drivers/acpi/numa/hmat.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-)