Add "-o debug" option to mount resctrl filesystem in debug mode. This
option is used for adding extra files to help resctrl debugging.
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
Documentation/arch/x86/resctrl.rst | 5 ++++-
arch/x86/kernel/cpu/resctrl/internal.h | 2 ++
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 20 ++++++++++++++++++++
3 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index af234681756e..5a2346d2c561 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -35,7 +35,7 @@ about the feature from resctrl's info directory.
To use the feature mount the file system::
- # mount -t resctrl resctrl [-o cdp[,cdpl2][,mba_MBps]] /sys/fs/resctrl
+ # mount -t resctrl resctrl [-o cdp[,cdpl2][,mba_MBps][,debug]] /sys/fs/resctrl
mount options are:
@@ -46,6 +46,9 @@ mount options are:
"mba_MBps":
Enable the MBA Software Controller(mba_sc) to specify MBA
bandwidth in MBps
+"debug":
+ Make debug files accessible. Available debug files are annotated with
+ "Available only with debug option".
L2 and L3 CDP are controlled separately.
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index 885b656d1088..5bc18accb887 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -59,6 +59,7 @@ struct rdt_fs_context {
bool enable_cdpl2;
bool enable_cdpl3;
bool enable_mba_mbps;
+ bool enable_debug;
};
static inline struct rdt_fs_context *rdt_fc2context(struct fs_context *fc)
@@ -296,6 +297,7 @@ struct rdtgroup {
#define RFTYPE_TOP BIT(6)
#define RFTYPE_RES_CACHE BIT(8)
#define RFTYPE_RES_MB BIT(9)
+#define RFTYPE_DEBUG BIT(10)
#define RFTYPE_CTRL_INFO (RFTYPE_INFO | RFTYPE_CTRL)
#define RFTYPE_MON_INFO (RFTYPE_INFO | RFTYPE_MON)
#define RFTYPE_TOP_INFO (RFTYPE_INFO | RFTYPE_TOP)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index e0570bce76a2..058c1dedb2d7 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -56,6 +56,8 @@ static char last_cmd_status_buf[512];
struct dentry *debugfs_resctrl;
+static bool resctrl_debug;
+
void rdt_last_cmd_clear(void)
{
lockdep_assert_held(&rdtgroup_mutex);
@@ -1871,6 +1873,9 @@ static int rdtgroup_add_files(struct kernfs_node *kn, unsigned long fflags)
lockdep_assert_held(&rdtgroup_mutex);
+ if (resctrl_debug)
+ fflags |= RFTYPE_DEBUG;
+
for (rft = rfts; rft < rfts + len; rft++) {
if (rft->fflags && ((fflags & rft->fflags) == rft->fflags)) {
ret = rdtgroup_add_file(kn, rft);
@@ -2399,6 +2404,9 @@ static int rdt_enable_ctx(struct rdt_fs_context *ctx)
goto out_cdpl3;
}
+ if (ctx->enable_debug)
+ resctrl_debug = true;
+
return 0;
out_cdpl3:
@@ -2591,6 +2599,8 @@ static int rdt_get_tree(struct fs_context *fc)
out_schemata_free:
schemata_list_destroy();
out_ctx:
+ if (ctx->enable_debug)
+ resctrl_debug = false;
if (ctx->enable_mba_mbps)
set_mba_sc(false);
cdp_disable_all();
@@ -2608,6 +2618,7 @@ enum rdt_param {
Opt_cdp,
Opt_cdpl2,
Opt_mba_mbps,
+ Opt_debug,
nr__rdt_params
};
@@ -2615,6 +2626,7 @@ static const struct fs_parameter_spec rdt_fs_parameters[] = {
fsparam_flag("cdp", Opt_cdp),
fsparam_flag("cdpl2", Opt_cdpl2),
fsparam_flag("mba_MBps", Opt_mba_mbps),
+ fsparam_flag("debug", Opt_debug),
{}
};
@@ -2640,6 +2652,9 @@ static int rdt_parse_param(struct fs_context *fc, struct fs_parameter *param)
return -EINVAL;
ctx->enable_mba_mbps = true;
return 0;
+ case Opt_debug:
+ ctx->enable_debug = true;
+ return 0;
}
return -EINVAL;
@@ -2829,6 +2844,8 @@ static void rdt_kill_sb(struct super_block *sb)
set_mba_sc(false);
+ resctrl_debug = false;
+
/*Put everything back to default values. */
for_each_alloc_capable_rdt_resource(r)
reset_all_ctrls(r);
@@ -3710,6 +3727,9 @@ static int rdtgroup_show_options(struct seq_file *seq, struct kernfs_root *kf)
if (is_mba_sc(&rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl))
seq_puts(seq, ",mba_MBps");
+ if (resctrl_debug)
+ seq_puts(seq, ",debug");
+
return 0;
}
Hi Babu, On 7/19/2023 4:22 PM, Babu Moger wrote: > @@ -2591,6 +2599,8 @@ static int rdt_get_tree(struct fs_context *fc) > out_schemata_free: > schemata_list_destroy(); > out_ctx: > + if (ctx->enable_debug) > + resctrl_debug = false; > if (ctx->enable_mba_mbps) > set_mba_sc(false); > cdp_disable_all(); These changes are a red flag to me. Developers still need to do what patch #4 was aiming to prevent. Reinette
Hi Reinette, On 8/4/23 15:42, Reinette Chatre wrote: > Hi Babu, > > On 7/19/2023 4:22 PM, Babu Moger wrote: >> @@ -2591,6 +2599,8 @@ static int rdt_get_tree(struct fs_context *fc) >> out_schemata_free: >> schemata_list_destroy(); >> out_ctx: >> + if (ctx->enable_debug) >> + resctrl_debug = false; >> if (ctx->enable_mba_mbps) >> set_mba_sc(false); >> cdp_disable_all(); > > These changes are a red flag to me. Developers still need to > do what patch #4 was aiming to prevent. I think you meant patch 5 (x86/resctrl: Unwind the errors inside rdt_enable_ctx). I can take care of this unwind part in rdt_disable_ctx() and call it here. https://lore.kernel.org/lkml/9fd70ef3-ca90-65e3-4746-7d574bdd159b@intel.com/#t Hope that is what you meant. -- Thanks Babu Moger
Hi Babu, On 8/8/2023 9:29 AM, Moger, Babu wrote: > On 8/4/23 15:42, Reinette Chatre wrote: >> Hi Babu, >> >> On 7/19/2023 4:22 PM, Babu Moger wrote: >>> @@ -2591,6 +2599,8 @@ static int rdt_get_tree(struct fs_context *fc) >>> out_schemata_free: >>> schemata_list_destroy(); >>> out_ctx: >>> + if (ctx->enable_debug) >>> + resctrl_debug = false; >>> if (ctx->enable_mba_mbps) >>> set_mba_sc(false); >>> cdp_disable_all(); >> >> These changes are a red flag to me. Developers still need to >> do what patch #4 was aiming to prevent. > > I think you meant patch 5 (x86/resctrl: Unwind the errors inside > rdt_enable_ctx). > > I can take care of this unwind part in rdt_disable_ctx() and call it here. > https://lore.kernel.org/lkml/9fd70ef3-ca90-65e3-4746-7d574bdd159b@intel.com/#t > > Hope that is what you meant. It is. Thank you for reading what I meant to write. Reinette
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