[4/9] x86/intel_rdt: Fix invalid mode warning when
diff mbox series

Message ID 1536957129-70380-5-git-send-email-fenghua.yu@intel.com
State New
Headers show
Series
  • x86/intel_rdt: MBA integration fixes
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Commit Message

Yu, Fenghua Sept. 14, 2018, 8:32 p.m. UTC
From: Reinette Chatre <reinette.chatre@intel.com>

multiple resources are managed

When multiple resources are managed by RDT, the number of CLOSIDs used
is the minimum of the CLOSIDs supported by each resource. In the function
rdt_bit_usage_show(), the annotated bitmask is created to depict how the
CAT supporting caches are being used. During this annotated bitmask
creation, each resource group is queried for its mode that is used as a
label in the annotated bitmask.

The maximum number of resource groups is currently assumed to be the
number of CLOSIDs supported by the resource for which the information is
being displayed. This is incorrect since the number of active CLOSIDs is
the minimum across all resources.

If information for a cache instance with more CLOSIDs than another is
being generated we thus encounter a warning like:

[  130.010591] ------------[ cut here ]------------
[  130.016680] invalid mode for closid 8
[  130.021791] WARNING: CPU: 88 PID: 1791 at [SNIP]/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
:827 rdt_bit_usage_show+0x221/0x2b0
[  130.037974] Modules linked in: intel_rapl x86_pkg_temp_thermal kvm ipmi_ssif iTCO_wdt vfat fat iTCO_vendor_support pcspkr irqbyp
ass lpc_ich ipmi_si ioatdma joydev i2c_i801 mfd_core ipmi_devintf dca wmi ipmi_msghandler acpi_pad i40e crct10dif_pclmul crc32_pclm
ul nvme crc32c_intel nvme_core sunrpc scsi_transport_iscsi
[  130.067581] CPU: 88 PID: 1791 Comm: grep Not tainted 4.18.0-rc1+ #18
[  130.075065] Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
[  130.087022] RIP: 0010:rdt_bit_usage_show+0x221/0x2b0
[  130.093365] Code: 45 84 c0 75 58 84 c0 74 42 be 50 00 00 00 4c 89 e7 e8 53 18 26 00 e9 30 ff ff ff 44 89 fe 48 c7 c7 ed f6 e4 95
 e8 4f d4 06 00 <0f> 0b e9 e3 fe ff ff 41 8b 45 00 09 44 24 08 e9 d6 fe ff ff 41 8b
[  130.113872] RSP: 0018:ffffa7874f147d88 EFLAGS: 00010286
[  130.120347] RAX: 0000000000000000 RBX: ffff8975434e0400 RCX: 0000000000000000
[  130.128963] RDX: ffff898d5f41dbd8 RSI: ffff898d5f415c78 RDI: ffff898d5f415c78
[  130.137562] RBP: ffffffff960285a0 R08: 00000000000005a4 R09: 0000000000aaaaaa
[  130.146158] R10: ffff898d3e040600 R11: 00000000ffffffff R12: ffff898d4b592000
[  130.154755] R13: ffff897543e62de0 R14: 0000000000000001 R15: 0000000000000008
[  130.163355] FS:  00007ff6f43dd740(0000) GS:ffff898d5f400000(0000) knlGS:0000000000000000
[  130.172920] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  130.180093] CR2: 000055b84a20f4d8 CR3: 0000002fcb5c6003 CR4: 00000000007606e0
[  130.187846] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  130.195091] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  130.202336] PKRU: 55555554
[  130.205093] Call Trace:
[  130.207588]  seq_read+0xee/0x460
[  130.210866]  __vfs_read+0x36/0x170
[  130.214324]  vfs_read+0x89/0x130
[  130.217605]  ksys_read+0x52/0xc0
[  130.220885]  do_syscall_64+0x5b/0x180
[  130.224609]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  130.229733] RIP: 0033:0x7ff6f3c88701

Fix this by ensuring that only the number of supported CLOSIDs are
considered.

Fixes: e651901187ab8 ("x86/intel_rdt: Introduce "bit_usage" to display cache allocations details")
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Reinette Chatre Sept. 15, 2018, 4:36 a.m. UTC | #1
On 9/14/2018 1:32 PM, Fenghua Yu wrote:
> From: Reinette Chatre <reinette.chatre@intel.com>
> 
> multiple resources are managed

The above snippet is redundant. We can remove it in the next version.

Reinette
Reinette Chatre Sept. 15, 2018, 4:47 a.m. UTC | #2
On 9/14/2018 9:36 PM, Reinette Chatre wrote:
> On 9/14/2018 1:32 PM, Fenghua Yu wrote:
>> From: Reinette Chatre <reinette.chatre@intel.com>
>>
>> multiple resources are managed
> 
> The above snippet is redundant. We can remove it in the next version.

Apologies, I responded too fast. The subject intended to read:
x86/intel_rdt: Fix invalid mode warning when multiple resources are managed

Reinette
Thomas Gleixner Sept. 15, 2018, 10:22 a.m. UTC | #3
On Fri, 14 Sep 2018, Fenghua Yu wrote:
> If information for a cache instance with more CLOSIDs than another is
> being generated we thus encounter a warning like:
> 
> [  130.010591] ------------[ cut here ]------------
> [  130.016680] invalid mode for closid 8
> [  130.021791] WARNING: CPU: 88 PID: 1791 at [SNIP]/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
> :827 rdt_bit_usage_show+0x221/0x2b0
> [  130.037974] Modules linked in: intel_rapl x86_pkg_temp_thermal kvm ipmi_ssif iTCO_wdt vfat fat iTCO_vendor_support pcspkr irqbyp
> ass lpc_ich ipmi_si ioatdma joydev i2c_i801 mfd_core ipmi_devintf dca wmi ipmi_msghandler acpi_pad i40e crct10dif_pclmul crc32_pclm
> ul nvme crc32c_intel nvme_core sunrpc scsi_transport_iscsi
> [  130.067581] CPU: 88 PID: 1791 Comm: grep Not tainted 4.18.0-rc1+ #18
> [  130.075065] Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.01.00.0833.051120182255 05/11/2018
> [  130.087022] RIP: 0010:rdt_bit_usage_show+0x221/0x2b0
> [  130.093365] Code: 45 84 c0 75 58 84 c0 74 42 be 50 00 00 00 4c 89 e7 e8 53 18 26 00 e9 30 ff ff ff 44 89 fe 48 c7 c7 ed f6 e4 95
>  e8 4f d4 06 00 <0f> 0b e9 e3 fe ff ff 41 8b 45 00 09 44 24 08 e9 d6 fe ff ff 41 8b
> [  130.113872] RSP: 0018:ffffa7874f147d88 EFLAGS: 00010286
> [  130.120347] RAX: 0000000000000000 RBX: ffff8975434e0400 RCX: 0000000000000000
> [  130.128963] RDX: ffff898d5f41dbd8 RSI: ffff898d5f415c78 RDI: ffff898d5f415c78
> [  130.137562] RBP: ffffffff960285a0 R08: 00000000000005a4 R09: 0000000000aaaaaa
> [  130.146158] R10: ffff898d3e040600 R11: 00000000ffffffff R12: ffff898d4b592000
> [  130.154755] R13: ffff897543e62de0 R14: 0000000000000001 R15: 0000000000000008
> [  130.163355] FS:  00007ff6f43dd740(0000) GS:ffff898d5f400000(0000) knlGS:0000000000000000
> [  130.172920] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  130.180093] CR2: 000055b84a20f4d8 CR3: 0000002fcb5c6003 CR4: 00000000007606e0
> [  130.187846] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  130.195091] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [  130.202336] PKRU: 55555554
> [  130.205093] Call Trace:
> [  130.207588]  seq_read+0xee/0x460
> [  130.210866]  __vfs_read+0x36/0x170
> [  130.214324]  vfs_read+0x89/0x130
> [  130.217605]  ksys_read+0x52/0xc0
> [  130.220885]  do_syscall_64+0x5b/0x180
> [  130.224609]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [  130.229733] RIP: 0033:0x7ff6f3c88701

Can you please condense all these backtraces to the absolute minimum?

In this case the only interresting part is:

 invalid mode for closid 8
 WARNING: CPU: 88 PID: 1791 at [SNIP]/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c:827
 rdt_bit_usage_show

and if at all a stripped stack trace:

 seq_read
 __vfs_read
 vfs_read
 ksys_read
 do_syscall_64

But think about it whether the stack trace provides actually useful
information or not. It's a well defined call chain.

The rest of the stuff I stripped is really completely irrelevant for
describing the problem. It just occupies space and distracts.

Thanks,

	tglx

Patch
diff mbox series

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index b372923eb209..ea91750ba27f 100644
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -809,7 +809,7 @@  static int rdt_bit_usage_show(struct kernfs_open_file *of,
 		sw_shareable = 0;
 		exclusive = 0;
 		seq_printf(seq, "%d=", dom->id);
-		for (i = 0; i < r->num_closid; i++, ctrl++) {
+		for (i = 0; i < closids_supported(); i++, ctrl++) {
 			if (!closid_allocated(i))
 				continue;
 			mode = rdtgroup_mode_by_closid(i);