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Subject[PATCH 2/6] x86/intel_rdt/mba_sc: Add support to enable/disable via mount option
Date
Specify a new mount option "mba_MB" to enable the user to specify MBA
bandwidth in Megabytes(Software Controller/SC) instead of b/w
percentage:

$mount -t resctrl resctrl [-o cdp[,cdpl2][mba_MB]] /sys/fs/resctrl

Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
---
arch/x86/kernel/cpu/intel_rdt.h | 5 +++++
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 31 +++++++++++++++++++++++++++++--
2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h
index 3fd7a70..3e9bc3f 100644
--- a/arch/x86/kernel/cpu/intel_rdt.h
+++ b/arch/x86/kernel/cpu/intel_rdt.h
@@ -259,6 +259,7 @@ struct rdt_cache {
* @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
+ * @bw_byte: True if memory B/W is specified in bytes
* @mb_map: Mapping of memory B/W percentage to memory B/W delay
*/
struct rdt_membw {
@@ -266,6 +267,7 @@ struct rdt_membw {
u32 min_bw;
u32 bw_gran;
u32 delay_linear;
+ bool bw_byte;
u32 *mb_map;
};

@@ -295,6 +297,9 @@ static inline bool is_mbm_event(int e)
e <= QOS_L3_MBM_LOCAL_EVENT_ID);
}

+#define is_mba_linear() rdt_resources_all[RDT_RESOURCE_MBA].membw.delay_linear
+#define is_mba_MBctrl() rdt_resources_all[RDT_RESOURCE_MBA].membw.bw_byte
+
/**
* struct rdt_resource - attributes of an RDT resource
* @rid: The index of the resource
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index fca759d..0707191 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1041,6 +1041,24 @@ static int set_cache_qos_cfg(int level, bool enable)
return 0;
}

+static void __set_mba_byte_ctrl(bool byte_ctrl)
+{
+ struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA];
+
+ r->membw.bw_byte = byte_ctrl;
+}
+
+/*
+ * MBA allocation in bytes is only supported if
+ * MBM is supported and MBA is in linear scale.
+*/
+static void set_mba_byte_ctrl(bool byte_ctrl)
+{
+ if ((is_mbm_enabled() && is_mba_linear()) &&
+ byte_ctrl != is_mba_MBctrl())
+ __set_mba_byte_ctrl(byte_ctrl);
+}
+
static int cdp_enable(int level, int data_type, int code_type)
{
struct rdt_resource *r_ldata = &rdt_resources_all[data_type];
@@ -1104,7 +1122,7 @@ static void cdp_disable_all(void)
cdpl2_disable();
}

-static int parse_rdtgroupfs_options(char *data)
+static int parse_rdtgroupfs_options(char *data, bool *mba_MBctrl)
{
char *token, *o = data;
int ret = 0;
@@ -1123,6 +1141,8 @@ static int parse_rdtgroupfs_options(char *data)
ret = cdpl2_enable();
if (ret)
goto out;
+ } else if (!strcmp(token, "mba_MB")) {
+ *mba_MBctrl = true;
} else {
ret = -EINVAL;
goto out;
@@ -1209,6 +1229,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
int flags, const char *unused_dev_name,
void *data)
{
+ bool mba_MBctrl = false;
struct rdt_domain *dom;
struct rdt_resource *r;
struct dentry *dentry;
@@ -1224,7 +1245,7 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
goto out;
}

- ret = parse_rdtgroupfs_options(data);
+ ret = parse_rdtgroupfs_options(data, &mba_MBctrl);
if (ret) {
dentry = ERR_PTR(ret);
goto out_cdp;
@@ -1277,6 +1298,9 @@ static struct dentry *rdt_mount(struct file_system_type *fs_type,
mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL);
}

+ if (mba_MBctrl)
+ set_mba_byte_ctrl(true);
+
goto out;

out_mondata:
@@ -1445,6 +1469,9 @@ static void rdt_kill_sb(struct super_block *sb)
cpus_read_lock();
mutex_lock(&rdtgroup_mutex);

+ /*Set the control values before the rest of reset*/
+ set_mba_byte_ctrl(false);
+
/*Put everything back to default values. */
for_each_alloc_enabled_rdt_resource(r)
reset_all_ctrls(r);
--
1.9.1
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