From: James Morse <james.morse@arm.com>
To: Babu Moger <babu.moger@amd.com>,
corbet@lwn.net, reinette.chatre@intel.com, tglx@linutronix.de,
mingo@redhat.com, bp@alien8.de
Cc: fenghua.yu@intel.com, dave.hansen@linux.intel.com,
x86@kernel.org, hpa@zytor.com, paulmck@kernel.org,
akpm@linux-foundation.org, quic_neeraju@quicinc.com,
rdunlap@infradead.org, damien.lemoal@opensource.wdc.com,
songmuchun@bytedance.com, peterz@infradead.org,
jpoimboe@kernel.org, pbonzini@redhat.com,
chang.seok.bae@intel.com, pawan.kumar.gupta@linux.intel.com,
jmattson@google.com, daniel.sneddon@linux.intel.com,
sandipan.das@amd.com, tony.luck@intel.com,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
bagasdotme@gmail.com, eranian@google.com
Subject: Re: [PATCH v4 01/13] x86/resctrl: Fix min_cbm_bits for AMD
Date: Fri, 9 Sep 2022 18:00:29 +0100 [thread overview]
Message-ID: <a60be378-dce6-08fb-02b8-1efc660ee3cb@arm.com> (raw)
In-Reply-To: <166257359679.1043018.9253512972611409799.stgit@bmoger-ubuntu>
Hi Babu,
On 07/09/2022 18:59, Babu Moger wrote:
> AMD systems support zero CBM (capacity bit mask) for L3 allocation.
> That is reflected in rdt_init_res_defs_amd() by:
>
> r->cache.arch_has_empty_bitmaps = true;
>
> However given the unified code in cbm_validate(), checking for:
> val == 0 && !arch_has_empty_bitmaps
>
> is not enough because of another check in cbm_validate():
>
> if ((zero_bit - first_bit) < r->cache.min_cbm_bits)
Right, the Intel version had this, but the AMD didn't. I evidently only thought about this
the !arch_has_empty_bitmaps way round! Sorry about that.
> The default value of r->cache.min_cbm_bits = 1.
>
> Leading to:
>
> $ cd /sys/fs/resctrl
> $ mkdir foo
> $ cd foo
> $ echo L3:0=0 > schemata
> -bash: echo: write error: Invalid argument
> $ cat /sys/fs/resctrl/info/last_cmd_status
> Need at least 1 bits in the mask
>
> Fix the issue by initializing the min_cbm_bits to 0 for AMD. Also,
> remove the default setting of min_cbm_bits and initialize it separately.
>
> After the fix
> $ cd /sys/fs/resctrl
> $ mkdir foo
> $ cd foo
> $ echo L3:0=0 > schemata
> $ cat /sys/fs/resctrl/info/last_cmd_status
> ok
>
> Link: https://lore.kernel.org/lkml/20220517001234.3137157-1-eranian@google.com/
> Fixes: 316e7f901f5a ("x86/resctrl: Add struct rdt_cache::arch_has_{sparse, empty}_bitmaps")
> Signed-off-by: Stephane Eranian <eranian@google.com>
> Signed-off-by: Babu Moger <babu.moger@amd.com>
Er, who is the author if this patch? If you are reposting Stephane's patch then there
needs to be a 'From: ' at the top of the email so that git preserves the ownership. You
may need some incantation of "git commit --amend --author=" to fix this in your tree.
As its a fix, have you posted this separately? Mixing fixes and new-code makes it hard for
the maintainer to spot what needs to be taken for the next -rc.
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index bb1c3f5f60c8..a5c51a14fbce 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -66,9 +66,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
> .rid = RDT_RESOURCE_L3,
> .name = "L3",
> .cache_level = 3,
> - .cache = {
> - .min_cbm_bits = 1,
> - },
> .domains = domain_init(RDT_RESOURCE_L3),
> .parse_ctrlval = parse_cbm,
> .format_str = "%d=%0*x",
> @@ -83,9 +80,6 @@ struct rdt_hw_resource rdt_resources_all[] = {
> .rid = RDT_RESOURCE_L2,
> .name = "L2",
> .cache_level = 2,
> - .cache = {
> - .min_cbm_bits = 1,
> - },
> .domains = domain_init(RDT_RESOURCE_L2),
> .parse_ctrlval = parse_cbm,
> .format_str = "%d=%0*x",
> @@ -877,6 +871,7 @@ static __init void rdt_init_res_defs_intel(void)
> r->cache.arch_has_sparse_bitmaps = false;
> r->cache.arch_has_empty_bitmaps = false;
> r->cache.arch_has_per_cpu_cfg = false;
> + r->cache.min_cbm_bits = 1;
> } else if (r->rid == RDT_RESOURCE_MBA) {
> hw_res->msr_base = MSR_IA32_MBA_THRTL_BASE;
> hw_res->msr_update = mba_wrmsr_intel;
> @@ -897,6 +892,7 @@ static __init void rdt_init_res_defs_amd(void)
> r->cache.arch_has_sparse_bitmaps = true;
> r->cache.arch_has_empty_bitmaps = true;
> r->cache.arch_has_per_cpu_cfg = true;
> + r->cache.min_cbm_bits = 0;
> } else if (r->rid == RDT_RESOURCE_MBA) {
> hw_res->msr_base = MSR_IA32_MBA_BW_BASE;
> hw_res->msr_update = mba_wrmsr_amd;
>
>
Reviewed-by: James Morse <james.morse@arm.com>
Thanks,
James
next prev parent reply other threads:[~2022-09-09 17:01 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-07 17:59 [PATCH v4 00/13] x86/resctrl: Support for AMD QoS new features and bug fix Babu Moger
2022-09-07 17:59 ` [PATCH v4 01/13] x86/resctrl: Fix min_cbm_bits for AMD Babu Moger
2022-09-09 17:00 ` James Morse [this message]
2022-09-12 14:54 ` Moger, Babu
2022-09-16 15:52 ` Reinette Chatre
2022-09-16 18:28 ` Moger, Babu
2022-09-16 15:53 ` Reinette Chatre
2022-09-16 18:31 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 02/13] x86/resctrl: Remove arch_has_empty_bitmaps Babu Moger
2022-09-16 15:53 ` Reinette Chatre
2022-09-16 19:00 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 03/13] x86/cpufeatures: Add Slow Memory Bandwidth Allocation feature flag Babu Moger
2022-09-16 15:54 ` Reinette Chatre
2022-09-16 19:02 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 04/13] x86/resctrl: Add a new resource type RDT_RESOURCE_SMBA Babu Moger
2022-09-16 15:54 ` Reinette Chatre
2022-09-16 19:11 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 05/13] x86/cpufeatures: Add Bandwidth Monitoring Event Configuration feature flag Babu Moger
2022-09-07 18:36 ` Daniel Sneddon
2022-09-07 19:59 ` Moger, Babu
2022-09-16 15:55 ` Reinette Chatre
2022-09-16 20:19 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 06/13] x86/resctrl: Include new features in command line options Babu Moger
2022-09-16 15:55 ` Reinette Chatre
2022-09-16 20:22 ` Moger, Babu
2022-09-07 18:00 ` [PATCH v4 07/13] x86/resctrl: Detect and configure Slow Memory Bandwidth allocation Babu Moger
2022-09-07 18:00 ` [PATCH v4 08/13] x86/resctrl : Introduce data structure to support monitor configuration Babu Moger
2022-09-16 15:56 ` Reinette Chatre
2022-09-16 21:23 ` Moger, Babu
2022-09-07 18:01 ` [PATCH v4 09/13] x86/resctrl: Add sysfs interface files to read/write event configuration Babu Moger
2022-09-16 15:58 ` Reinette Chatre
2022-09-19 15:46 ` Moger, Babu
2022-09-19 16:42 ` Reinette Chatre
2022-09-19 20:26 ` Moger, Babu
2022-09-19 21:07 ` Reinette Chatre
2022-09-20 17:09 ` Moger, Babu
2022-09-07 18:01 ` [PATCH v4 10/13] x86/resctrl: Add the sysfs interface to read the " Babu Moger
2022-09-16 15:59 ` Reinette Chatre
2022-09-19 16:07 ` Moger, Babu
2022-09-07 18:01 ` [PATCH v4 11/13] x86/resctrl: Add sysfs interface to write " Babu Moger
2022-09-16 16:17 ` Reinette Chatre
2022-09-19 16:50 ` Moger, Babu
2022-09-07 18:01 ` [PATCH v4 12/13] x86/resctrl: Replace smp_call_function_many with on_each_cpu_mask Babu Moger
2022-09-16 16:17 ` Reinette Chatre
2022-09-16 20:38 ` Moger, Babu
2022-09-07 18:01 ` [PATCH v4 13/13] Documentation/x86: Update resctrl_ui.rst for new features Babu Moger
2022-09-08 4:07 ` Bagas Sanjaya
2022-09-08 9:26 ` Bagas Sanjaya
2022-09-08 13:40 ` Moger, Babu
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