[PATCH 00/10] x86/resctrl: Misc cleanup

[PATCH 00/10] x86/resctrl: Misc cleanup

[James Morse]

Hello!

These are the miscellaneous cleanup patches that floated to the top of
the MPAM tree. (more on that story later).

The only interesting thing are the patches to make the AMD/Intel
differences something resctrl understands, instead of just 'happening'
because of the different function pointers.
This will become more important once MPAM support is added. parse_bw()
and friends are what enforces resctrl's ABI resctrl. Allowing an
architecture/platform to provide a subtly different function here would
be bad for user-space.

MPAM would set arch_has_sparse_bitmaps, but not arch_needs_linear.

Nothing in this series should change any behaviour.
This series is based on v5.6-rc1.


Thanks,

James Morse (10):
  x86/resctrl: Nothing uses struct mbm_state chunks_bw
  x86/resctrl: Remove max_delay
  x86/resctrl: Fix stale comment
  x86/resctrl: use container_of() in delayed_work handlers
  x86/resctrl: Include pid.h
  x86/resctrl: Use is_closid_match() in more places
  x86/resctrl: Add arch_needs_linear to explain AMD/Intel MBA difference
  x86/resctrl: Merge AMD/Intel parse_bw() calls
  x86/resctrl: Add arch_has_sparse_bitmaps to explain AMD/Intel CAT
    difference
  cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file

 arch/x86/kernel/cpu/resctrl/core.c        | 36 ++++------
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 87 +++--------------------
 arch/x86/kernel/cpu/resctrl/internal.h    | 19 ++---
 arch/x86/kernel/cpu/resctrl/monitor.c     | 15 +---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 32 ++++-----
 include/linux/cacheinfo.h                 | 18 +++++
 include/linux/resctrl.h                   |  2 +
 7 files changed, 67 insertions(+), 142 deletions(-)

-- 
2.24.1

[PATCH 01/10] x86/resctrl: Nothing uses struct mbm_state chunks_bw

[James Morse]

Nothing reads struct mbm_states's chunks_bw value, its a copy of
chunks. Remove it.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/internal.h | 2 --
 arch/x86/kernel/cpu/resctrl/monitor.c  | 3 +--
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 181c992f448c..90ca6a090c77 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -275,7 +275,6 @@ struct rftype {
  * struct mbm_state - status for each MBM counter in each domain
  * @chunks:	Total data moved (multiply by rdt_group.mon_scale to get bytes)
  * @prev_msr	Value of IA32_QM_CTR for this RMID last time we read it
- * @chunks_bw	Total local data moved. Used for bandwidth calculation
  * @prev_bw_msr:Value of previous IA32_QM_CTR for bandwidth counting
  * @prev_bw	The most recent bandwidth in MBps
  * @delta_bw	Difference between the current and previous bandwidth
@@ -284,7 +283,6 @@ struct rftype {
 struct mbm_state {
 	u64	chunks;
 	u64	prev_msr;
-	u64	chunks_bw;
 	u64	prev_bw_msr;
 	u32	prev_bw;
 	u32	delta_bw;
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 773124b0e18a..af549df38ec6 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -279,8 +279,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
 		return;
 
 	chunks = mbm_overflow_count(m->prev_bw_msr, tval);
-	m->chunks_bw += chunks;
-	m->chunks = m->chunks_bw;
+	m->chunks += chunks;
 	cur_bw = (chunks * r->mon_scale) >> 20;
 
 	if (m->delta_comp)
-- 
2.24.1

Re: [PATCH 01/10] x86/resctrl: Nothing uses struct mbm_state chunks_bw

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> Nothing reads struct mbm_states's chunks_bw value, its a copy of
> chunks. Remove it.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 02/10] x86/resctrl: Remove max_delay

[James Morse]

max_delay is used by x86's rdt_get_mem_config() as a local variable.
Remove it, replacing it with a local variable.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/core.c     | 8 ++++----
 arch/x86/kernel/cpu/resctrl/internal.h | 3 ---
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 89049b343c7a..7d295ae620bb 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -254,16 +254,16 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 {
 	union cpuid_0x10_3_eax eax;
 	union cpuid_0x10_x_edx edx;
-	u32 ebx, ecx;
+	u32 ebx, ecx, max_delay;
 
 	cpuid_count(0x00000010, 3, &eax.full, &ebx, &ecx, &edx.full);
 	r->num_closid = edx.split.cos_max + 1;
-	r->membw.max_delay = eax.split.max_delay + 1;
+	max_delay = eax.split.max_delay + 1;
 	r->default_ctrl = MAX_MBA_BW;
 	if (ecx & MBA_IS_LINEAR) {
 		r->membw.delay_linear = true;
-		r->membw.min_bw = MAX_MBA_BW - r->membw.max_delay;
-		r->membw.bw_gran = MAX_MBA_BW - r->membw.max_delay;
+		r->membw.min_bw = MAX_MBA_BW - max_delay;
+		r->membw.bw_gran = MAX_MBA_BW - max_delay;
 	} else {
 		if (!rdt_get_mb_table(r))
 			return false;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 90ca6a090c77..3e3ba85843c4 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -361,8 +361,6 @@ struct rdt_cache {
 
 /**
  * struct rdt_membw - Memory bandwidth allocation related data
- * @max_delay:		Max throttle delay. Delay is the hardware
- *			representation for memory bandwidth.
  * @min_bw:		Minimum memory bandwidth percentage user can request
  * @bw_gran:		Granularity at which the memory bandwidth is allocated
  * @delay_linear:	True if memory B/W delay is in linear scale
@@ -370,7 +368,6 @@ struct rdt_cache {
  * @mb_map:		Mapping of memory B/W percentage to memory B/W delay
  */
 struct rdt_membw {
-	u32		max_delay;
 	u32		min_bw;
 	u32		bw_gran;
 	u32		delay_linear;
-- 
2.24.1

Re: [PATCH 02/10] x86/resctrl: Remove max_delay

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> max_delay is used by x86's rdt_get_mem_config() as a local variable.

get_mem_config() may be more appropriate since rdt_get_mem_config() does
not exist, __get_mem_config_intel() would be most accurate.

> Remove it, replacing it with a local variable.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---

Apart from the above ...

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 03/10] x86/resctrl: Fix stale comment

[James Morse]

The comment in rdtgroup_init() refers to the non existent function
rdt_mount(), which has now been renamed rdt_get_tree(). Fix the
comment.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 064e9ef44cd6..fef09105cbe4 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -3181,7 +3181,7 @@ int __init rdtgroup_init(void)
 	 * It may also be ok since that would enable debugging of RDT before
 	 * resctrl is mounted.
 	 * The reason why the debugfs directory is created here and not in
-	 * rdt_mount() is because rdt_mount() takes rdtgroup_mutex and
+	 * rdt_get_tree() is because rdt_get_tree() takes rdtgroup_mutex and
 	 * during the debugfs directory creation also &sb->s_type->i_mutex_key
 	 * (the lockdep class of inode->i_rwsem). Other filesystem
 	 * interactions (eg. SyS_getdents) have the lock ordering:
-- 
2.24.1

Re: [PATCH 03/10] x86/resctrl: Fix stale comment

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> The comment in rdtgroup_init() refers to the non existent function
> rdt_mount(), which has now been renamed rdt_get_tree(). Fix the
> comment.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 04/10] x86/resctrl: use container_of() in delayed_work handlers

[James Morse]

mbm_handle_overflow() and cqm_handle_limbo() are both provided with
the domain's work_struct when called, but use get_domain_from_cpu()
to find the domain, along with the appropriate error handling.

container_of() saves some list walking and bitmap testing, use that
instead.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/monitor.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index af549df38ec6..a02a7f886a0a 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -476,19 +476,13 @@ void cqm_handle_limbo(struct work_struct *work)
 	mutex_lock(&rdtgroup_mutex);
 
 	r = &rdt_resources_all[RDT_RESOURCE_L3];
-	d = get_domain_from_cpu(cpu, r);
-
-	if (!d) {
-		pr_warn_once("Failure to get domain for limbo worker\n");
-		goto out_unlock;
-	}
+	d = container_of(work, struct rdt_domain, cqm_limbo.work);
 
 	__check_limbo(d, false);
 
 	if (has_busy_rmid(r, d))
 		schedule_delayed_work_on(cpu, &d->cqm_limbo, delay);
 
-out_unlock:
 	mutex_unlock(&rdtgroup_mutex);
 }
 
@@ -516,9 +510,7 @@ void mbm_handle_overflow(struct work_struct *work)
 	if (!static_branch_likely(&rdt_mon_enable_key))
 		goto out_unlock;
 
-	d = get_domain_from_cpu(cpu, &rdt_resources_all[RDT_RESOURCE_L3]);
-	if (!d)
-		goto out_unlock;
+	d = container_of(work, struct rdt_domain, mbm_over.work);
 
 	list_for_each_entry(prgrp, &rdt_all_groups, rdtgroup_list) {
 		mbm_update(d, prgrp->mon.rmid);
-- 
2.24.1

Re: [PATCH 04/10] x86/resctrl: use container_of() in delayed_work handlers

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> mbm_handle_overflow() and cqm_handle_limbo() are both provided with
> the domain's work_struct when called, but use get_domain_from_cpu()
> to find the domain, along with the appropriate error handling.
> 
> container_of() saves some list walking and bitmap testing, use that
> instead.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 05/10] x86/resctrl: Include pid.h

[James Morse]

We are about to disturb the header soup. This header uses struct pid
and struct pid_namespace. Include their header.

Signed-off-by: James Morse <james.morse@arm.com>
---
 include/linux/resctrl.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index daf5cf64c6a6..9b05af9b3e28 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -2,6 +2,8 @@
 #ifndef _RESCTRL_H
 #define _RESCTRL_H
 
+#include <linux/pid.h>
+
 #ifdef CONFIG_PROC_CPU_RESCTRL
 
 int proc_resctrl_show(struct seq_file *m,
-- 
2.24.1

Re: [PATCH 05/10] x86/resctrl: Include pid.h

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> We are about to disturb the header soup. This header uses struct pid
> and struct pid_namespace. Include their header.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 06/10] x86/resctrl: Use is_closid_match() in more places

[James Morse]

rdtgroup_tasks_assigned() and show_rdt_tasks() loop over threads testing
for a CTRL/MON group match by closid/rmid with the provided rdtgrp.
Further down the file are helpers to do this, move these further up and
make use of them here.

These helpers additionally check for alloc/mon capable. This is harmless
as rdtgroup_mkdir() tests these capable flags before allowing the config
directories to be created.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 30 ++++++++++++--------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index fef09105cbe4..c84b1f355a9a 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -592,6 +592,18 @@ static int __rdtgroup_move_task(struct task_struct *tsk,
 	return ret;
 }
 
+static bool is_closid_match(struct task_struct *t, struct rdtgroup *r)
+{
+	return (rdt_alloc_capable &&
+	       (r->type == RDTCTRL_GROUP) && (t->closid == r->closid));
+}
+
+static bool is_rmid_match(struct task_struct *t, struct rdtgroup *r)
+{
+	return (rdt_mon_capable &&
+	       (r->type == RDTMON_GROUP) && (t->rmid == r->mon.rmid));
+}
+
 /**
  * rdtgroup_tasks_assigned - Test if tasks have been assigned to resource group
  * @r: Resource group
@@ -607,8 +619,7 @@ int rdtgroup_tasks_assigned(struct rdtgroup *r)
 
 	rcu_read_lock();
 	for_each_process_thread(p, t) {
-		if ((r->type == RDTCTRL_GROUP && t->closid == r->closid) ||
-		    (r->type == RDTMON_GROUP && t->rmid == r->mon.rmid)) {
+		if (is_closid_match(t, r) || is_rmid_match(t, r)) {
 			ret = 1;
 			break;
 		}
@@ -706,8 +717,7 @@ static void show_rdt_tasks(struct rdtgroup *r, struct seq_file *s)
 
 	rcu_read_lock();
 	for_each_process_thread(p, t) {
-		if ((r->type == RDTCTRL_GROUP && t->closid == r->closid) ||
-		    (r->type == RDTMON_GROUP && t->rmid == r->mon.rmid))
+		if (is_closid_match(t, r) || is_rmid_match(t, r))
 			seq_printf(s, "%d\n", t->pid);
 	}
 	rcu_read_unlock();
@@ -2231,18 +2241,6 @@ static int reset_all_ctrls(struct rdt_resource *r)
 	return 0;
 }
 
-static bool is_closid_match(struct task_struct *t, struct rdtgroup *r)
-{
-	return (rdt_alloc_capable &&
-		(r->type == RDTCTRL_GROUP) && (t->closid == r->closid));
-}
-
-static bool is_rmid_match(struct task_struct *t, struct rdtgroup *r)
-{
-	return (rdt_mon_capable &&
-		(r->type == RDTMON_GROUP) && (t->rmid == r->mon.rmid));
-}
-
 /*
  * Move tasks from one to the other group. If @from is NULL, then all tasks
  * in the systems are moved unconditionally (used for teardown).
-- 
2.24.1

Re: [PATCH 06/10] x86/resctrl: Use is_closid_match() in more places

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> rdtgroup_tasks_assigned() and show_rdt_tasks() loop over threads testing
> for a CTRL/MON group match by closid/rmid with the provided rdtgrp.
> Further down the file are helpers to do this, move these further up and
> make use of them here.
> 
> These helpers additionally check for alloc/mon capable. This is harmless
> as rdtgroup_mkdir() tests these capable flags before allowing the config
> directories to be created.
> 
> Signed-off-by: James Morse <james.morse@arm.com>

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 07/10] x86/resctrl: Add arch_needs_linear to explain AMD/Intel MBA difference

[James Morse]

The configuration values user-space provides to the resctrl filesystem
are ABI. To make this work on another architecture we want to move all
the ABI bits out of /arch/x86 and under /fs.

To do this, the differences between AMD and Intel CPUs needs to be
explained to resctrl via resource properties, instead of function
pointers that let the arch code accept subtly different values on
different platforms/architectures.

For MBA, Intel CPUs reject configuration attempts for non-linear
resources, whereas AMD ignore this field as its MBA resource is never
linear. To merge the parse/validate functions we need to explain
this difference.

Add arch_needs_linear to indicate the arch code needs the linear
property to be true to configure this resource. AMD can set this
and delay_linear to false. Intel can set arch_needs_linear
to true to keep the existing "No support for non-linear MB domains"
error message for affected platforms.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/core.c        | 3 +++
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 8 +++++++-
 arch/x86/kernel/cpu/resctrl/internal.h    | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 7d295ae620bb..f022dc823c53 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -260,6 +260,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 	r->num_closid = edx.split.cos_max + 1;
 	max_delay = eax.split.max_delay + 1;
 	r->default_ctrl = MAX_MBA_BW;
+	r->membw.arch_needs_linear = true;
 	if (ecx & MBA_IS_LINEAR) {
 		r->membw.delay_linear = true;
 		r->membw.min_bw = MAX_MBA_BW - max_delay;
@@ -267,6 +268,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
 	} else {
 		if (!rdt_get_mb_table(r))
 			return false;
+		r->membw.arch_needs_linear = false;
 	}
 	r->data_width = 3;
 
@@ -288,6 +290,7 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
 
 	/* AMD does not use delay */
 	r->membw.delay_linear = false;
+	r->membw.arch_needs_linear = false;
 
 	r->membw.min_bw = 0;
 	r->membw.bw_gran = 1;
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 055c8613b531..db8e6c0cadb1 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -33,6 +33,12 @@ static bool bw_validate_amd(char *buf, unsigned long *data,
 	unsigned long bw;
 	int ret;
 
+	/* temporary: always false on AMD */
+	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
+		rdt_last_cmd_puts("No support for non-linear MB domains\n");
+		return false;
+	}
+
 	ret = kstrtoul(buf, 10, &bw);
 	if (ret) {
 		rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
@@ -82,7 +88,7 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
 	/*
 	 * Only linear delay values is supported for current Intel SKUs.
 	 */
-	if (!r->membw.delay_linear) {
+	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
 		rdt_last_cmd_puts("No support for non-linear MB domains\n");
 		return false;
 	}
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 3e3ba85843c4..1fa692c54e15 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -363,6 +363,7 @@ struct rdt_cache {
  * struct rdt_membw - Memory bandwidth allocation related data
  * @min_bw:		Minimum memory bandwidth percentage user can request
  * @bw_gran:		Granularity at which the memory bandwidth is allocated
+ * @arch_needs_linear:  True if we can't configure non-linear resources
  * @delay_linear:	True if memory B/W delay is in linear scale
  * @mba_sc:		True if MBA software controller(mba_sc) is enabled
  * @mb_map:		Mapping of memory B/W percentage to memory B/W delay
@@ -371,6 +372,7 @@ struct rdt_membw {
 	u32		min_bw;
 	u32		bw_gran;
 	u32		delay_linear;
+	bool		arch_needs_linear;
 	bool		mba_sc;
 	u32		*mb_map;
 };
-- 
2.24.1

Re: [PATCH 07/10] x86/resctrl: Add arch_needs_linear to explain AMD/Intel MBA difference

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> The configuration values user-space provides to the resctrl filesystem
> are ABI. To make this work on another architecture we want to move all
> the ABI bits out of /arch/x86 and under /fs.
> 
> To do this, the differences between AMD and Intel CPUs needs to be
> explained to resctrl via resource properties, instead of function
> pointers that let the arch code accept subtly different values on
> different platforms/architectures.
> 
> For MBA, Intel CPUs reject configuration attempts for non-linear
> resources, whereas AMD ignore this field as its MBA resource is never
> linear. To merge the parse/validate functions we need to explain
> this difference.
> 
> Add arch_needs_linear to indicate the arch code needs the linear
> property to be true to configure this resource. AMD can set this
> and delay_linear to false. Intel can set arch_needs_linear
> to true to keep the existing "No support for non-linear MB domains"
> error message for affected platforms.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  arch/x86/kernel/cpu/resctrl/core.c        | 3 +++
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 8 +++++++-
>  arch/x86/kernel/cpu/resctrl/internal.h    | 2 ++
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 7d295ae620bb..f022dc823c53 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -260,6 +260,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
>  	r->num_closid = edx.split.cos_max + 1;
>  	max_delay = eax.split.max_delay + 1;
>  	r->default_ctrl = MAX_MBA_BW;
> +	r->membw.arch_needs_linear = true;
>  	if (ecx & MBA_IS_LINEAR) {
>  		r->membw.delay_linear = true;
>  		r->membw.min_bw = MAX_MBA_BW - max_delay;
> @@ -267,6 +268,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
>  	} else {
>  		if (!rdt_get_mb_table(r))
>  			return false;
> +		r->membw.arch_needs_linear = false;
>  	}
>  	r->data_width = 3;
>  
> @@ -288,6 +290,7 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
>  
>  	/* AMD does not use delay */
>  	r->membw.delay_linear = false;
> +	r->membw.arch_needs_linear = false;
>  
>  	r->membw.min_bw = 0;
>  	r->membw.bw_gran = 1;
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index 055c8613b531..db8e6c0cadb1 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -33,6 +33,12 @@ static bool bw_validate_amd(char *buf, unsigned long *data,
>  	unsigned long bw;
>  	int ret;
>  
> +	/* temporary: always false on AMD */
> +	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
> +		rdt_last_cmd_puts("No support for non-linear MB domains\n");
> +		return false;
> +	}
> +
>  	ret = kstrtoul(buf, 10, &bw);
>  	if (ret) {
>  		rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
> @@ -82,7 +88,7 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
>  	/*
>  	 * Only linear delay values is supported for current Intel SKUs.
>  	 */
> -	if (!r->membw.delay_linear) {
> +	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
>  		rdt_last_cmd_puts("No support for non-linear MB domains\n");
>  		return false;
>  	}
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 3e3ba85843c4..1fa692c54e15 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -363,6 +363,7 @@ struct rdt_cache {
>   * struct rdt_membw - Memory bandwidth allocation related data
>   * @min_bw:		Minimum memory bandwidth percentage user can request
>   * @bw_gran:		Granularity at which the memory bandwidth is allocated
> + * @arch_needs_linear:  True if we can't configure non-linear resources
>   * @delay_linear:	True if memory B/W delay is in linear scale
>   * @mba_sc:		True if MBA software controller(mba_sc) is enabled
>   * @mb_map:		Mapping of memory B/W percentage to memory B/W delay

This area uses tab for spacing.

> @@ -371,6 +372,7 @@ struct rdt_membw {
>  	u32		min_bw;
>  	u32		bw_gran;
>  	u32		delay_linear;
> +	bool		arch_needs_linear;
>  	bool		mba_sc;
>  	u32		*mb_map;
>  };
> 

Babu may want to take a look.

Just the one small comment from my side, apart from that it looks good
to me.

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Thank you

Reinette

[PATCH 08/10] x86/resctrl: Merge AMD/Intel parse_bw() calls

[James Morse]

Now that we've explained arch_needs_linear to resctrl, the parse_bw()
calls are almost the same between AMD and Intel.

The difference is '!is_mba_sc()', which is not checked on AMD. This
will always be true on AMD CPUs as mba_sc cannot be enabled as
is_mba_linear() is false.

Removing this duplication means user-space visible behaviour and
error messages are not validated or generated in different places.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/core.c        |  4 +-
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 55 +----------------------
 arch/x86/kernel/cpu/resctrl/internal.h    |  6 +--
 3 files changed, 5 insertions(+), 60 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index f022dc823c53..e90c10ca85f4 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -924,7 +924,7 @@ static __init void rdt_init_res_defs_intel(void)
 		else if (r->rid == RDT_RESOURCE_MBA) {
 			r->msr_base = MSR_IA32_MBA_THRTL_BASE;
 			r->msr_update = mba_wrmsr_intel;
-			r->parse_ctrlval = parse_bw_intel;
+			r->parse_ctrlval = parse_bw;
 		}
 	}
 }
@@ -944,7 +944,7 @@ static __init void rdt_init_res_defs_amd(void)
 		else if (r->rid == RDT_RESOURCE_MBA) {
 			r->msr_base = MSR_IA32_MBA_BW_BASE;
 			r->msr_update = mba_wrmsr_amd;
-			r->parse_ctrlval = parse_bw_amd;
+			r->parse_ctrlval = parse_bw;
 		}
 	}
 }
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index db8e6c0cadb1..416becb591d1 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -21,59 +21,6 @@
 #include <linux/slab.h>
 #include "internal.h"
 
-/*
- * Check whether MBA bandwidth percentage value is correct. The value is
- * checked against the minimum and maximum bandwidth values specified by
- * the hardware. The allocated bandwidth percentage is rounded to the next
- * control step available on the hardware.
- */
-static bool bw_validate_amd(char *buf, unsigned long *data,
-			    struct rdt_resource *r)
-{
-	unsigned long bw;
-	int ret;
-
-	/* temporary: always false on AMD */
-	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
-		rdt_last_cmd_puts("No support for non-linear MB domains\n");
-		return false;
-	}
-
-	ret = kstrtoul(buf, 10, &bw);
-	if (ret) {
-		rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
-		return false;
-	}
-
-	if (bw < r->membw.min_bw || bw > r->default_ctrl) {
-		rdt_last_cmd_printf("MB value %ld out of range [%d,%d]\n", bw,
-				    r->membw.min_bw, r->default_ctrl);
-		return false;
-	}
-
-	*data = roundup(bw, (unsigned long)r->membw.bw_gran);
-	return true;
-}
-
-int parse_bw_amd(struct rdt_parse_data *data, struct rdt_resource *r,
-		 struct rdt_domain *d)
-{
-	unsigned long bw_val;
-
-	if (d->have_new_ctrl) {
-		rdt_last_cmd_printf("Duplicate domain %d\n", d->id);
-		return -EINVAL;
-	}
-
-	if (!bw_validate_amd(data->buf, &bw_val, r))
-		return -EINVAL;
-
-	d->new_ctrl = bw_val;
-	d->have_new_ctrl = true;
-
-	return 0;
-}
-
 /*
  * Check whether MBA bandwidth percentage value is correct. The value is
  * checked against the minimum and max bandwidth values specified by the
@@ -110,7 +57,7 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
 	return true;
 }
 
-int parse_bw_intel(struct rdt_parse_data *data, struct rdt_resource *r,
+int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
 		   struct rdt_domain *d)
 {
 	unsigned long bw_val;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 1fa692c54e15..45fc695081d1 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -462,10 +462,8 @@ struct rdt_resource {
 
 int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
 	      struct rdt_domain *d);
-int parse_bw_intel(struct rdt_parse_data *data, struct rdt_resource *r,
-		   struct rdt_domain *d);
-int parse_bw_amd(struct rdt_parse_data *data, struct rdt_resource *r,
-		 struct rdt_domain *d);
+int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
+	     struct rdt_domain *d);
 
 extern struct mutex rdtgroup_mutex;
 
-- 
2.24.1

Re: [PATCH 08/10] x86/resctrl: Merge AMD/Intel parse_bw() calls

[Reinette Chatre]

Hi James,

On 2/14/2020 10:23 AM, James Morse wrote:
> Now that we've explained arch_needs_linear to resctrl, the parse_bw()
> calls are almost the same between AMD and Intel.
> 
> The difference is '!is_mba_sc()', which is not checked on AMD. This
> will always be true on AMD CPUs as mba_sc cannot be enabled as
> is_mba_linear() is false.
> 
> Removing this duplication means user-space visible behaviour and
> error messages are not validated or generated in different places.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  arch/x86/kernel/cpu/resctrl/core.c        |  4 +-
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 55 +----------------------
>  arch/x86/kernel/cpu/resctrl/internal.h    |  6 +--
>  3 files changed, 5 insertions(+), 60 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index f022dc823c53..e90c10ca85f4 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -924,7 +924,7 @@ static __init void rdt_init_res_defs_intel(void)
>  		else if (r->rid == RDT_RESOURCE_MBA) {
>  			r->msr_base = MSR_IA32_MBA_THRTL_BASE;
>  			r->msr_update = mba_wrmsr_intel;
> -			r->parse_ctrlval = parse_bw_intel;
> +			r->parse_ctrlval = parse_bw;
>  		}
>  	}
>  }
> @@ -944,7 +944,7 @@ static __init void rdt_init_res_defs_amd(void)
>  		else if (r->rid == RDT_RESOURCE_MBA) {
>  			r->msr_base = MSR_IA32_MBA_BW_BASE;
>  			r->msr_update = mba_wrmsr_amd;
> -			r->parse_ctrlval = parse_bw_amd;
> +			r->parse_ctrlval = parse_bw;
>  		}
>  	}
>  }

Now that these values are identical more duplication can be avoided by
moving the initialization to earlier where rdt_resources_all[] is
initialized. Could you please modify this patch to do so?

> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index db8e6c0cadb1..416becb591d1 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -21,59 +21,6 @@
>  #include <linux/slab.h>
>  #include "internal.h"
>  
> -/*
> - * Check whether MBA bandwidth percentage value is correct. The value is
> - * checked against the minimum and maximum bandwidth values specified by
> - * the hardware. The allocated bandwidth percentage is rounded to the next
> - * control step available on the hardware.
> - */
> -static bool bw_validate_amd(char *buf, unsigned long *data,
> -			    struct rdt_resource *r)
> -{
> -	unsigned long bw;
> -	int ret;
> -
> -	/* temporary: always false on AMD */
> -	if (!r->membw.delay_linear && r->membw.arch_needs_linear) {
> -		rdt_last_cmd_puts("No support for non-linear MB domains\n");
> -		return false;
> -	}
> -
> -	ret = kstrtoul(buf, 10, &bw);
> -	if (ret) {
> -		rdt_last_cmd_printf("Non-decimal digit in MB value %s\n", buf);
> -		return false;
> -	}
> -
> -	if (bw < r->membw.min_bw || bw > r->default_ctrl) {
> -		rdt_last_cmd_printf("MB value %ld out of range [%d,%d]\n", bw,
> -				    r->membw.min_bw, r->default_ctrl);
> -		return false;
> -	}
> -
> -	*data = roundup(bw, (unsigned long)r->membw.bw_gran);
> -	return true;
> -}
> -
> -int parse_bw_amd(struct rdt_parse_data *data, struct rdt_resource *r,
> -		 struct rdt_domain *d)
> -{
> -	unsigned long bw_val;
> -
> -	if (d->have_new_ctrl) {
> -		rdt_last_cmd_printf("Duplicate domain %d\n", d->id);
> -		return -EINVAL;
> -	}
> -
> -	if (!bw_validate_amd(data->buf, &bw_val, r))
> -		return -EINVAL;
> -
> -	d->new_ctrl = bw_val;
> -	d->have_new_ctrl = true;
> -
> -	return 0;
> -}
> -
>  /*
>   * Check whether MBA bandwidth percentage value is correct. The value is
>   * checked against the minimum and max bandwidth values specified by the
> @@ -110,7 +57,7 @@ static bool bw_validate(char *buf, unsigned long *data, struct rdt_resource *r)
>  	return true;
>  }
>  
> -int parse_bw_intel(struct rdt_parse_data *data, struct rdt_resource *r,
> +int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
>  		   struct rdt_domain *d)

This change affects the alignment here ... could you please fix the
alignment to match open parenthesis?

>  {
>  	unsigned long bw_val;
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 1fa692c54e15..45fc695081d1 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -462,10 +462,8 @@ struct rdt_resource {
>  
>  int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
>  	      struct rdt_domain *d);
> -int parse_bw_intel(struct rdt_parse_data *data, struct rdt_resource *r,
> -		   struct rdt_domain *d);
> -int parse_bw_amd(struct rdt_parse_data *data, struct rdt_resource *r,
> -		 struct rdt_domain *d);
> +int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
> +	     struct rdt_domain *d);
>  
>  extern struct mutex rdtgroup_mutex;
>  
> 

Babu may want to take a look also.

Thank you

Reinette

[PATCH 09/10] x86/resctrl: Add arch_has_sparse_bitmaps to explain AMD/Intel CAT difference

[James Morse]

Intel expects the cache bitmap provided by user-space to have on a
single span of 1s, whereas AMD can support bitmaps like 0xf00f.
Arm's MPAM support also allows sparse bitmaps.

To move resctrl out to /fs/ we need to explain platform differences
like this. Add a resource property arch_has_sparse_bitmaps. Test this
around the 'non-consecutive' test in cbm_validate().

Merging the validate calls causes AMD top gain the min_cbm_bits test
needed for Haswell, but as it always sets this value to 1, it will
never match.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/core.c        |  4 +--
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 36 +++++------------------
 arch/x86/kernel/cpu/resctrl/internal.h    |  6 ++--
 3 files changed, 12 insertions(+), 34 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index e90c10ca85f4..7c9c4bd5fd32 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -920,7 +920,7 @@ static __init void rdt_init_res_defs_intel(void)
 		    r->rid == RDT_RESOURCE_L2 ||
 		    r->rid == RDT_RESOURCE_L2DATA ||
 		    r->rid == RDT_RESOURCE_L2CODE)
-			r->cbm_validate = cbm_validate_intel;
+			r->cache.arch_has_sparse_bitmaps = false;
 		else if (r->rid == RDT_RESOURCE_MBA) {
 			r->msr_base = MSR_IA32_MBA_THRTL_BASE;
 			r->msr_update = mba_wrmsr_intel;
@@ -940,7 +940,7 @@ static __init void rdt_init_res_defs_amd(void)
 		    r->rid == RDT_RESOURCE_L2 ||
 		    r->rid == RDT_RESOURCE_L2DATA ||
 		    r->rid == RDT_RESOURCE_L2CODE)
-			r->cbm_validate = cbm_validate_amd;
+			r->cache.arch_has_sparse_bitmaps = true;
 		else if (r->rid == RDT_RESOURCE_MBA) {
 			r->msr_base = MSR_IA32_MBA_BW_BASE;
 			r->msr_update = mba_wrmsr_amd;
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 416becb591d1..38df876feb54 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -76,12 +76,14 @@ int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
 }
 
 /*
- * Check whether a cache bit mask is valid. The SDM says:
+ * Check whether a cache bit mask is valid.
+ * For Intel The SDM says:
  *	Please note that all (and only) contiguous '1' combinations
  *	are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
  * Additionally Haswell requires at least two bits set.
+ * AMD allows non-contiguous bitmasks.
  */
-bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
+static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
 {
 	unsigned long first_bit, zero_bit, val;
 	unsigned int cbm_len = r->cache.cbm_len;
@@ -101,7 +103,9 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
 	first_bit = find_first_bit(&val, cbm_len);
 	zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);
 
-	if (find_next_bit(&val, cbm_len, zero_bit) < cbm_len) {
+	/* Are non-contiguous bitmaps allowed? */
+	if (!r->cache.arch_has_sparse_bitmaps &&
+	    (find_next_bit(&val, cbm_len, zero_bit) < cbm_len)) {
 		rdt_last_cmd_printf("The mask %lx has non-consecutive 1-bits\n", val);
 		return false;
 	}
@@ -116,30 +120,6 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
 	return true;
 }
 
-/*
- * Check whether a cache bit mask is valid. AMD allows non-contiguous
- * bitmasks
- */
-bool cbm_validate_amd(char *buf, u32 *data, struct rdt_resource *r)
-{
-	unsigned long val;
-	int ret;
-
-	ret = kstrtoul(buf, 16, &val);
-	if (ret) {
-		rdt_last_cmd_printf("Non-hex character in the mask %s\n", buf);
-		return false;
-	}
-
-	if (val > r->default_ctrl) {
-		rdt_last_cmd_puts("Mask out of range\n");
-		return false;
-	}
-
-	*data = val;
-	return true;
-}
-
 /*
  * Read one cache bit mask (hex). Check that it is valid for the current
  * resource type.
@@ -165,7 +145,7 @@ int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
 		return -EINVAL;
 	}
 
-	if (!r->cbm_validate(data->buf, &cbm_val, r))
+	if (!cbm_validate(data->buf, &cbm_val, r))
 		return -EINVAL;
 
 	if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 45fc695081d1..0172a87de814 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -350,6 +350,7 @@ struct msr_param {
  *			in a cache bit mask
  * @shareable_bits:	Bitmask of shareable resource with other
  *			executing entities
+ * @arch_has_sparse_bitmaps:   True if a bitmap like f00f is valid.
  */
 struct rdt_cache {
 	unsigned int	cbm_len;
@@ -357,6 +358,7 @@ struct rdt_cache {
 	unsigned int	cbm_idx_mult;
 	unsigned int	cbm_idx_offset;
 	unsigned int	shareable_bits;
+	bool		arch_has_sparse_bitmaps;
 };
 
 /**
@@ -426,7 +428,6 @@ struct rdt_parse_data {
  * @cache:		Cache allocation related data
  * @format_str:		Per resource format string to show domain value
  * @parse_ctrlval:	Per resource function pointer to parse control values
- * @cbm_validate	Cache bitmask validate function
  * @evt_list:		List of monitoring events
  * @num_rmid:		Number of RMIDs available
  * @mon_scale:		cqm counter * mon_scale = occupancy in bytes
@@ -453,7 +454,6 @@ struct rdt_resource {
 	int (*parse_ctrlval)(struct rdt_parse_data *data,
 			     struct rdt_resource *r,
 			     struct rdt_domain *d);
-	bool (*cbm_validate)(char *buf, u32 *data, struct rdt_resource *r);
 	struct list_head	evt_list;
 	int			num_rmid;
 	unsigned int		mon_scale;
@@ -594,7 +594,5 @@ void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms);
 void cqm_handle_limbo(struct work_struct *work);
 bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
 void __check_limbo(struct rdt_domain *d, bool force_free);
-bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r);
-bool cbm_validate_amd(char *buf, u32 *data, struct rdt_resource *r);
 
 #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
-- 
2.24.1

Re: [PATCH 09/10] x86/resctrl: Add arch_has_sparse_bitmaps to explain AMD/Intel CAT difference

[Reinette Chatre]

Hi James,

On 2/14/2020 10:24 AM, James Morse wrote:
> Intel expects the cache bitmap provided by user-space to have on a
> single span of 1s, whereas AMD can support bitmaps like 0xf00f.
> Arm's MPAM support also allows sparse bitmaps.
> 
> To move resctrl out to /fs/ we need to explain platform differences
> like this. Add a resource property arch_has_sparse_bitmaps. Test this
> around the 'non-consecutive' test in cbm_validate().
> 
> Merging the validate calls causes AMD top gain the min_cbm_bits test
> needed for Haswell, but as it always sets this value to 1, it will
> never match.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  arch/x86/kernel/cpu/resctrl/core.c        |  4 +--
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 36 +++++------------------
>  arch/x86/kernel/cpu/resctrl/internal.h    |  6 ++--
>  3 files changed, 12 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index e90c10ca85f4..7c9c4bd5fd32 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -920,7 +920,7 @@ static __init void rdt_init_res_defs_intel(void)
>  		    r->rid == RDT_RESOURCE_L2 ||
>  		    r->rid == RDT_RESOURCE_L2DATA ||
>  		    r->rid == RDT_RESOURCE_L2CODE)
> -			r->cbm_validate = cbm_validate_intel;
> +			r->cache.arch_has_sparse_bitmaps = false;
>  		else if (r->rid == RDT_RESOURCE_MBA) {
>  			r->msr_base = MSR_IA32_MBA_THRTL_BASE;
>  			r->msr_update = mba_wrmsr_intel;
> @@ -940,7 +940,7 @@ static __init void rdt_init_res_defs_amd(void)
>  		    r->rid == RDT_RESOURCE_L2 ||
>  		    r->rid == RDT_RESOURCE_L2DATA ||
>  		    r->rid == RDT_RESOURCE_L2CODE)
> -			r->cbm_validate = cbm_validate_amd;
> +			r->cache.arch_has_sparse_bitmaps = true;
>  		else if (r->rid == RDT_RESOURCE_MBA) {
>  			r->msr_base = MSR_IA32_MBA_BW_BASE;
>  			r->msr_update = mba_wrmsr_amd;
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index 416becb591d1..38df876feb54 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -76,12 +76,14 @@ int parse_bw(struct rdt_parse_data *data, struct rdt_resource *r,
>  }
>  
>  /*
> - * Check whether a cache bit mask is valid. The SDM says:
> + * Check whether a cache bit mask is valid.
> + * For Intel The SDM says:

s/The/the/

>   *	Please note that all (and only) contiguous '1' combinations
>   *	are allowed (e.g. FFFFH, 0FF0H, 003CH, etc.).
>   * Additionally Haswell requires at least two bits set.
> + * AMD allows non-contiguous bitmasks.
>   */
> -bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
> +static bool cbm_validate(char *buf, u32 *data, struct rdt_resource *r)
>  {
>  	unsigned long first_bit, zero_bit, val;
>  	unsigned int cbm_len = r->cache.cbm_len;
> @@ -101,7 +103,9 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
>  	first_bit = find_first_bit(&val, cbm_len);
>  	zero_bit = find_next_zero_bit(&val, cbm_len, first_bit);
>  
> -	if (find_next_bit(&val, cbm_len, zero_bit) < cbm_len) {
> +	/* Are non-contiguous bitmaps allowed? */
> +	if (!r->cache.arch_has_sparse_bitmaps &&
> +	    (find_next_bit(&val, cbm_len, zero_bit) < cbm_len)) {
>  		rdt_last_cmd_printf("The mask %lx has non-consecutive 1-bits\n", val);
>  		return false;
>  	}
> @@ -116,30 +120,6 @@ bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r)
>  	return true;
>  }
>  
> -/*
> - * Check whether a cache bit mask is valid. AMD allows non-contiguous
> - * bitmasks
> - */
> -bool cbm_validate_amd(char *buf, u32 *data, struct rdt_resource *r)
> -{
> -	unsigned long val;
> -	int ret;
> -
> -	ret = kstrtoul(buf, 16, &val);
> -	if (ret) {
> -		rdt_last_cmd_printf("Non-hex character in the mask %s\n", buf);
> -		return false;
> -	}
> -
> -	if (val > r->default_ctrl) {
> -		rdt_last_cmd_puts("Mask out of range\n");
> -		return false;
> -	}
> -
> -	*data = val;
> -	return true;
> -}
> -
>  /*
>   * Read one cache bit mask (hex). Check that it is valid for the current
>   * resource type.
> @@ -165,7 +145,7 @@ int parse_cbm(struct rdt_parse_data *data, struct rdt_resource *r,
>  		return -EINVAL;
>  	}
>  
> -	if (!r->cbm_validate(data->buf, &cbm_val, r))
> +	if (!cbm_validate(data->buf, &cbm_val, r))
>  		return -EINVAL;
>  
>  	if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 45fc695081d1..0172a87de814 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -350,6 +350,7 @@ struct msr_param {
>   *			in a cache bit mask
>   * @shareable_bits:	Bitmask of shareable resource with other
>   *			executing entities
> + * @arch_has_sparse_bitmaps:   True if a bitmap like f00f is valid.
>   */

This area uses tab for spacing.

>  struct rdt_cache {
>  	unsigned int	cbm_len;
> @@ -357,6 +358,7 @@ struct rdt_cache {
>  	unsigned int	cbm_idx_mult;
>  	unsigned int	cbm_idx_offset;
>  	unsigned int	shareable_bits;
> +	bool		arch_has_sparse_bitmaps;
>  };
>  
>  /**
> @@ -426,7 +428,6 @@ struct rdt_parse_data {
>   * @cache:		Cache allocation related data
>   * @format_str:		Per resource format string to show domain value
>   * @parse_ctrlval:	Per resource function pointer to parse control values
> - * @cbm_validate	Cache bitmask validate function
>   * @evt_list:		List of monitoring events
>   * @num_rmid:		Number of RMIDs available
>   * @mon_scale:		cqm counter * mon_scale = occupancy in bytes
> @@ -453,7 +454,6 @@ struct rdt_resource {
>  	int (*parse_ctrlval)(struct rdt_parse_data *data,
>  			     struct rdt_resource *r,
>  			     struct rdt_domain *d);
> -	bool (*cbm_validate)(char *buf, u32 *data, struct rdt_resource *r);
>  	struct list_head	evt_list;
>  	int			num_rmid;
>  	unsigned int		mon_scale;
> @@ -594,7 +594,5 @@ void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms);
>  void cqm_handle_limbo(struct work_struct *work);
>  bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
>  void __check_limbo(struct rdt_domain *d, bool force_free);
> -bool cbm_validate_intel(char *buf, u32 *data, struct rdt_resource *r);
> -bool cbm_validate_amd(char *buf, u32 *data, struct rdt_resource *r);
>  
>  #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
> 

Just the two small comments from my side. For the rest:

Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Babu may want to take a look.

Reinette

[PATCH 10/10] cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file

[James Morse]

resctrl/core.c defines get_cache_id() for use in its cpu-hotplug
callbacks. This gets the id attribute of the cache at the corresponding
level of a cpu.

Later rework means this private function needs to be shared. Move
it to the header file.

The name conflicts with a different definition in intel_cacheinfo.c,
name it get_cpu_cacheinfo_id() to show its relation with
get_cpu_cacheinfo().

Now this is visible on other architectures, check the id attribute
has actually been set.

Signed-off-by: James Morse <james.morse@arm.com>
---
 arch/x86/kernel/cpu/resctrl/core.c | 17 ++---------------
 include/linux/cacheinfo.h          | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 7c9c4bd5fd32..f2968fb6fb9a 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -349,19 +349,6 @@ static void rdt_get_cdp_l2_config(void)
 	rdt_get_cdp_config(RDT_RESOURCE_L2, RDT_RESOURCE_L2CODE);
 }
 
-static int get_cache_id(int cpu, int level)
-{
-	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
-	int i;
-
-	for (i = 0; i < ci->num_leaves; i++) {
-		if (ci->info_list[i].level == level)
-			return ci->info_list[i].id;
-	}
-
-	return -1;
-}
-
 static void
 mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
 {
@@ -559,7 +546,7 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
  */
 static void domain_add_cpu(int cpu, struct rdt_resource *r)
 {
-	int id = get_cache_id(cpu, r->cache_level);
+	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
 	struct list_head *add_pos = NULL;
 	struct rdt_domain *d;
 
@@ -603,7 +590,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
 
 static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 {
-	int id = get_cache_id(cpu, r->cache_level);
+	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
 	struct rdt_domain *d;
 
 	d = rdt_find_domain(r, id, NULL);
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 46b92cd61d0c..e210225ab7a8 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -3,6 +3,7 @@
 #define _LINUX_CACHEINFO_H
 
 #include <linux/bitops.h>
+#include <linux/cpu.h>
 #include <linux/cpumask.h>
 #include <linux/smp.h>
 
@@ -119,4 +120,21 @@ int acpi_find_last_cache_level(unsigned int cpu);
 
 const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
 
+/* Get the id of a particular cache on @cpu. cpuhp lock must held. */
+static inline int get_cpu_cacheinfo_id(int cpu, int level)
+{
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
+	int i;
+
+	for (i = 0; i < ci->num_leaves; i++) {
+		if (ci->info_list[i].level == level){
+			if (ci->info_list[i].attributes & CACHE_ID)
+				return ci->info_list[i].id;
+			return -1;
+		}
+	}
+
+	return -1;
+}
+
 #endif /* _LINUX_CACHEINFO_H */
-- 
2.24.1

Re: [PATCH 10/10] cacheinfo: Move resctrl's get_cache_id() to the cacheinfo header file

[Reinette Chatre]

Hi James,

On 2/14/2020 10:24 AM, James Morse wrote:
> resctrl/core.c defines get_cache_id() for use in its cpu-hotplug
> callbacks. This gets the id attribute of the cache at the corresponding
> level of a cpu.
> 
> Later rework means this private function needs to be shared. Move
> it to the header file.
> 
> The name conflicts with a different definition in intel_cacheinfo.c,
> name it get_cpu_cacheinfo_id() to show its relation with
> get_cpu_cacheinfo().
> 
> Now this is visible on other architectures, check the id attribute
> has actually been set.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  arch/x86/kernel/cpu/resctrl/core.c | 17 ++---------------
>  include/linux/cacheinfo.h          | 18 ++++++++++++++++++
>  2 files changed, 20 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 7c9c4bd5fd32..f2968fb6fb9a 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -349,19 +349,6 @@ static void rdt_get_cdp_l2_config(void)
>  	rdt_get_cdp_config(RDT_RESOURCE_L2, RDT_RESOURCE_L2CODE);
>  }
>  
> -static int get_cache_id(int cpu, int level)
> -{
> -	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
> -	int i;
> -
> -	for (i = 0; i < ci->num_leaves; i++) {
> -		if (ci->info_list[i].level == level)
> -			return ci->info_list[i].id;
> -	}
> -
> -	return -1;
> -}
> -
>  static void
>  mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
>  {
> @@ -559,7 +546,7 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
>   */
>  static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  {
> -	int id = get_cache_id(cpu, r->cache_level);
> +	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
>  	struct list_head *add_pos = NULL;
>  	struct rdt_domain *d;
>  
> @@ -603,7 +590,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  
>  static void domain_remove_cpu(int cpu, struct rdt_resource *r)
>  {
> -	int id = get_cache_id(cpu, r->cache_level);
> +	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
>  	struct rdt_domain *d;
>  
>  	d = rdt_find_domain(r, id, NULL);
> diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
> index 46b92cd61d0c..e210225ab7a8 100644
> --- a/include/linux/cacheinfo.h
> +++ b/include/linux/cacheinfo.h
> @@ -3,6 +3,7 @@
>  #define _LINUX_CACHEINFO_H
>  
>  #include <linux/bitops.h>
> +#include <linux/cpu.h>
>  #include <linux/cpumask.h>
>  #include <linux/smp.h>
>  
> @@ -119,4 +120,21 @@ int acpi_find_last_cache_level(unsigned int cpu);
>  
>  const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
>  
> +/* Get the id of a particular cache on @cpu. cpuhp lock must held. */

Technically the cache is not _on_ @cpu. How about "Get the id of the
cache associated with @cpu at level @level"?

Also, s/must held/must be held/

> +static inline int get_cpu_cacheinfo_id(int cpu, int level)
> +{
> +	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
> +	int i;
> +
> +	for (i = 0; i < ci->num_leaves; i++) {
> +		if (ci->info_list[i].level == level){

Typo here. Could you please insert a space before the open brace?

> +			if (ci->info_list[i].attributes & CACHE_ID)
> +				return ci->info_list[i].id;
> +			return -1;
> +		}
> +	}
> +
> +	return -1;
> +}
> +
>  #endif /* _LINUX_CACHEINFO_H */
> 

The resctrl bits look good to me.

Thank you

Reinette