Re: [PATCH v5 2/8] x86/resctrl: Prepare for different scope for control/monitor operations
From: Tony Luck
Date: Thu Sep 28 2023 - 13:21:59 EST
On Mon, Sep 25, 2023 at 04:24:10PM -0700, Reinette Chatre wrote:
> Hi Tony,
>
> On 8/29/2023 4:44 PM, Tony Luck wrote:
> > Existing resctrl assumes that control and monitor operations on a
>
> Please remove "Existing", it can just be "resctrl assumes ..."
Will do.
>
> > resource are performed at the same scope.
> >
> > Prepare for systems that use different scope (specifically L3 scope
> > for cache control and NODE scope for cache occupancy and memory
> > bandwidth monitoring).
> >
> > Create separate domain lists for control and monitor operations.
> >
> > No important functional change. But note that errors during
> > initialization of either control or monitor functions on a domain would
> > previously result in that domain being excluded from both control and
> > monitor operations. Now the domains are allocated independently it is
> > no longer required to disable both control and monitor operations if
> > either fail.
> >
> > Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> > ---
> > include/linux/resctrl.h | 16 +-
> > arch/x86/kernel/cpu/resctrl/internal.h | 6 +-
> > arch/x86/kernel/cpu/resctrl/core.c | 227 +++++++++++++++-------
> > arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +-
> > arch/x86/kernel/cpu/resctrl/monitor.c | 2 +-
> > arch/x86/kernel/cpu/resctrl/pseudo_lock.c | 2 +-
> > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 32 +--
> > 7 files changed, 199 insertions(+), 88 deletions(-)
> >
> > diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> > index 2db1244ae642..33856943a787 100644
> > --- a/include/linux/resctrl.h
> > +++ b/include/linux/resctrl.h
> > @@ -155,10 +155,12 @@ enum resctrl_scope {
> > * @alloc_capable: Is allocation available on this machine
> > * @mon_capable: Is monitor feature available on this machine
> > * @num_rmid: Number of RMIDs available
> > - * @scope: Scope of this resource
> > + * @ctrl_scope: Scope of this resource for control functions
> > + * @mon_scope: Scope of this resource for monitor functions
> > * @cache: Cache allocation related data
> > * @membw: If the component has bandwidth controls, their properties.
> > - * @domains: All domains for this resource
> > + * @domains: Control domains for this resource
> > + * @mon_domains: Monitor domains for this resource
> > * @name: Name to use in "schemata" file.
> > * @data_width: Character width of data when displaying
> > * @default_ctrl: Specifies default cache cbm or memory B/W percent.
> > @@ -173,10 +175,12 @@ struct rdt_resource {
> > bool alloc_capable;
> > bool mon_capable;
> > int num_rmid;
> > - enum resctrl_scope scope;
> > + enum resctrl_scope ctrl_scope;
> > + enum resctrl_scope mon_scope;
> > struct resctrl_cache cache;
> > struct resctrl_membw membw;
> > struct list_head domains;
> > + struct list_head mondomains;
>
> kerneldoc is "mon_domains" while member is "mondomains".
> I do think to be consistent with other members that "mon_domains"
> would be appropriate. I also think it will be very helpful it
> domains is renamed to "ctrl_domains" to more accurately match
> "ctrl_scope" and what it represents.
Next version will use "mon_domains" (and "mon_" in all the associated
functions and macros). I'm also changing to "ctrl_" as suggested.
> > char *name;
> > int data_width;
> > u32 default_ctrl;
> > @@ -222,8 +226,10 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_domain *d,
> >
> > u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
> > u32 closid, enum resctrl_conf_type type);
> > -int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d);
> > -void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
> > +int resctrl_online_ctrl_domain(struct rdt_resource *r, struct rdt_domain *d);
> > +int resctrl_online_mon_domain(struct rdt_resource *r, struct rdt_domain *d);
> > +void resctrl_offline_ctrl_domain(struct rdt_resource *r, struct rdt_domain *d);
> > +void resctrl_offline_mon_domain(struct rdt_resource *r, struct rdt_domain *d);
> >
> > /**
> > * resctrl_arch_rmid_read() - Read the eventid counter corresponding to rmid
> > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> > index 85ceaf9a31ac..31a5fc3b717f 100644
> > --- a/arch/x86/kernel/cpu/resctrl/internal.h
> > +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> > @@ -511,8 +511,10 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn);
> > int rdtgroup_kn_mode_restrict(struct rdtgroup *r, const char *name);
> > int rdtgroup_kn_mode_restore(struct rdtgroup *r, const char *name,
> > umode_t mask);
> > -struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> > - struct list_head **pos);
> > +struct rdt_domain *rdt_find_ctrldomain(struct list_head *h, int id,
> > + struct list_head **pos);
> > +struct rdt_domain *rdt_find_mondomain(struct list_head *h, int id,
> > + struct list_head **pos);
>
> This is not what I expected after our previous discussion. It
> should not be necessary for caller to be aware of the different
> lists. It looks to me like the original parameters of (struct rdt_resource *r,
> int id, struct list_head **pos) can be maintained.
Discussed in other e-mail. There is now a "struct rdt_domain_hdr"
embedded in the control and monitor versions of the domain structure.
rdt_find_domain() operates on that, and callers user container_of() to
get to the enclosing structure.
>
> > ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
> > char *buf, size_t nbytes, loff_t off);
> > int rdtgroup_schemata_show(struct kernfs_open_file *of,
> > diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> > index 0d3bae523ecb..97f6f9715fdb 100644
> > --- a/arch/x86/kernel/cpu/resctrl/core.c
> > +++ b/arch/x86/kernel/cpu/resctrl/core.c
> > @@ -57,7 +57,7 @@ static void
> > mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m,
> > struct rdt_resource *r);
> >
> > -#define domain_init(id) LIST_HEAD_INIT(rdt_resources_all[id].r_resctrl.domains)
> > +#define domain_init(id, field) LIST_HEAD_INIT(rdt_resources_all[id].r_resctrl.field)
> >
>
> It may make the code easier to read if this is split into
> a "mon_domain_init()" and "ctrl_domain_init()"
Done
>
> > struct rdt_hw_resource rdt_resources_all[] = {
> > [RDT_RESOURCE_L3] =
> > @@ -65,8 +65,10 @@ struct rdt_hw_resource rdt_resources_all[] = {
> > .r_resctrl = {
> > .rid = RDT_RESOURCE_L3,
> > .name = "L3",
> > - .scope = RESCTRL_L3_CACHE,
> > - .domains = domain_init(RDT_RESOURCE_L3),
> > + .ctrl_scope = RESCTRL_L3_CACHE,
> > + .mon_scope = RESCTRL_L3_CACHE,
> > + .domains = domain_init(RDT_RESOURCE_L3, domains),
> > + .mondomains = domain_init(RDT_RESOURCE_L3, mondomains),
> > .parse_ctrlval = parse_cbm,
> > .format_str = "%d=%0*x",
> > .fflags = RFTYPE_RES_CACHE,
> > @@ -79,8 +81,8 @@ struct rdt_hw_resource rdt_resources_all[] = {
> > .r_resctrl = {
> > .rid = RDT_RESOURCE_L2,
> > .name = "L2",
> > - .scope = RESCTRL_L2_CACHE,
> > - .domains = domain_init(RDT_RESOURCE_L2),
> > + .ctrl_scope = RESCTRL_L2_CACHE,
> > + .domains = domain_init(RDT_RESOURCE_L2, domains),
> > .parse_ctrlval = parse_cbm,
> > .format_str = "%d=%0*x",
> > .fflags = RFTYPE_RES_CACHE,
> > @@ -93,8 +95,8 @@ struct rdt_hw_resource rdt_resources_all[] = {
> > .r_resctrl = {
> > .rid = RDT_RESOURCE_MBA,
> > .name = "MB",
> > - .scope = RESCTRL_L3_CACHE,
> > - .domains = domain_init(RDT_RESOURCE_MBA),
> > + .ctrl_scope = RESCTRL_L3_CACHE,
> > + .domains = domain_init(RDT_RESOURCE_MBA, domains),
> > .parse_ctrlval = parse_bw,
> > .format_str = "%d=%*u",
> > .fflags = RFTYPE_RES_MB,
> > @@ -105,8 +107,8 @@ struct rdt_hw_resource rdt_resources_all[] = {
> > .r_resctrl = {
> > .rid = RDT_RESOURCE_SMBA,
> > .name = "SMBA",
> > - .scope = RESCTRL_L3_CACHE,
> > - .domains = domain_init(RDT_RESOURCE_SMBA),
> > + .ctrl_scope = RESCTRL_L3_CACHE,
> > + .domains = domain_init(RDT_RESOURCE_SMBA, domains),
> > .parse_ctrlval = parse_bw,
> > .format_str = "%d=%*u",
> > .fflags = RFTYPE_RES_MB,
> > @@ -384,15 +386,16 @@ void rdt_ctrl_update(void *arg)
> > }
> >
> > /*
> > - * rdt_find_domain - Find a domain in a resource that matches input resource id
> > + * __rdt_find_domain - Find a domain in either the list of control or
> > + * monitor domains that matches input resource id
> > *
> > * Search resource r's domain list to find the resource id. If the resource
> > * id is found in a domain, return the domain. Otherwise, if requested by
> > * caller, return the first domain whose id is bigger than the input id.
> > * The domain list is sorted by id in ascending order.
> > */
> > -struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> > - struct list_head **pos)
> > +static void *__rdt_find_domain(struct list_head *h, int id,
> > + struct list_head **pos)
> > {
> > struct rdt_domain *d;
> > struct list_head *l;
> > @@ -400,7 +403,7 @@ struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> > if (id < 0)
> > return ERR_PTR(-ENODEV);
> >
> > - list_for_each(l, &r->domains) {
> > + list_for_each(l, h) {
> > d = list_entry(l, struct rdt_domain, list);
> > /* When id is found, return its domain. */
> > if (id == d->id)
> > @@ -416,6 +419,18 @@ struct rdt_domain *rdt_find_domain(struct rdt_resource *r, int id,
> > return NULL;
> > }
> >
> > +struct rdt_domain *rdt_find_ctrldomain(struct list_head *h, int id,
> > + struct list_head **pos)
> > +{
> > + return __rdt_find_domain(h, id, pos);
> > +}
> > +
> > +struct rdt_domain *rdt_find_mondomain(struct list_head *h, int id,
> > + struct list_head **pos)
> > +{
> > + return __rdt_find_domain(h, id, pos);
> > +}
> > +
> > static void setup_default_ctrlval(struct rdt_resource *r, u32 *dc)
> > {
> > struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> > @@ -431,10 +446,15 @@ static void setup_default_ctrlval(struct rdt_resource *r, u32 *dc)
> > }
> >
> > static void domain_free(struct rdt_hw_domain *hw_dom)
> > +{
> > + kfree(hw_dom->ctrl_val);
> > + kfree(hw_dom);
> > +}
> > +
> > +static void mondomain_free(struct rdt_hw_domain *hw_dom)
> > {
> > kfree(hw_dom->arch_mbm_total);
> > kfree(hw_dom->arch_mbm_local);
> > - kfree(hw_dom->ctrl_val);
> > kfree(hw_dom);
> > }
> >
> > @@ -502,6 +522,93 @@ static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
> > return -1;
> > }
> >
> > +static void domain_add_cpu_ctrl(int cpu, struct rdt_resource *r)
> > +{
> > + int id = get_domain_id_from_scope(cpu, r->ctrl_scope);
> > + struct list_head *add_pos = NULL;
> > + struct rdt_hw_domain *hw_dom;
> > + struct rdt_domain *d;
> > + int err;
> > +
> > + d = rdt_find_ctrldomain(&r->domains, id, &add_pos);
> > + if (IS_ERR(d)) {
> > + pr_warn("Couldn't find scope id=%d for CPU %d\n", id, cpu);
>
> I am not sure here ... this generates identical error messages
> for control and monitor domain. How will the user know what failed?
> Also, how does printing id help? If I understand correctly it can
> only be -1 when the above prints.
Improved error messages in next version. Separate ones for failure in
get_domain_id_from_scope() and rdt_find_domain(). Each have "control"
or "monitor" in the message to help the user pinpoint exactly what
went wrong.
> > + return;
> > + }
> > +
> > + if (d) {
> > + cpumask_set_cpu(cpu, &d->cpu_mask);
> > + if (r->cache.arch_has_per_cpu_cfg)
> > + rdt_domain_reconfigure_cdp(r);
> > + return;
> > + }
> > +
> > + hw_dom = kzalloc_node(sizeof(*hw_dom), GFP_KERNEL, cpu_to_node(cpu));
> > + if (!hw_dom)
> > + return;
> > +
> > + d = &hw_dom->d_resctrl;
> > + d->id = id;
> > + cpumask_set_cpu(cpu, &d->cpu_mask);
> > +
> > + rdt_domain_reconfigure_cdp(r);
> > +
> > + if (domain_setup_ctrlval(r, d)) {
> > + domain_free(hw_dom);
> > + return;
> > + }
> > +
> > + list_add_tail(&d->list, add_pos);
> > +
> > + err = resctrl_online_ctrl_domain(r, d);
> > + if (err) {
> > + list_del(&d->list);
> > + domain_free(hw_dom);
> > + }
> > +}
> > +
> > +static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
> > +{
> > + int id = get_domain_id_from_scope(cpu, r->mon_scope);
> > + struct rdt_hw_domain *hw_mondom;
> > + struct list_head *add_pos = NULL;
>
> Please maintain reverse fir ordering. Please check all code.
I believe I got them all (for functions that are touched by this
series - there are a handful of places in resctrl code that don't
have reverse fir ordering - I didn't touch those).
> > + struct rdt_domain *d;
> > + int err;
> > +
> > + d = rdt_find_mondomain(&r->mondomains, id, &add_pos);
> > + if (IS_ERR(d)) {
> > + pr_warn("Couldn't find scope id=%d for CPU %d\n", id, cpu);
> > + return;
> > + }
> > +
> > + if (d) {
> > + cpumask_set_cpu(cpu, &d->cpu_mask);
> > +
>
> This is an unnecessary empty line that distracts from how the rest
> of the function looks.
Deleted it.
>
> > + return;
> > + }
> > +
> > + hw_mondom = kzalloc_node(sizeof(*hw_mondom), GFP_KERNEL, cpu_to_node(cpu));
> > + if (!hw_mondom)
> > + return;
> > +
> > + d = &hw_mondom->d_resctrl;
> > + d->id = id;
> > + cpumask_set_cpu(cpu, &d->cpu_mask);
> > +
> > + if (arch_domain_mbm_alloc(r->num_rmid, hw_mondom)) {
> > + mondomain_free(hw_mondom);
> > + return;
> > + }
> > +
> > + list_add_tail(&d->list, add_pos);
> > +
> > + err = resctrl_online_mon_domain(r, d);
> > + if (err) {
> > + list_del(&d->list);
> > + mondomain_free(hw_mondom);
> > + }
> > +}
> > +
> > /*
> > * domain_add_cpu - Add a cpu to a resource's domain list.
> > *
>
> Note that this leaves the comments about list management here while all
> the list management code is moved away.
Moved the comment in front of rdt_find_domain() which does most of the
work. Small edit in the comment to say that callers do the rest.
>
> > @@ -517,70 +624,28 @@ static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
> > */
> > static void domain_add_cpu(int cpu, struct rdt_resource *r)
> > {
> > - int id = get_domain_id_from_scope(cpu, r->scope);
> > - struct list_head *add_pos = NULL;
> > - struct rdt_hw_domain *hw_dom;
> > - struct rdt_domain *d;
> > - int err;
> > -
> > - d = rdt_find_domain(r, id, &add_pos);
> > - if (IS_ERR(d)) {
> > - pr_warn("Couldn't find cache id for CPU %d\n", cpu);
> > - return;
> > - }
> > -
> > - if (d) {
> > - cpumask_set_cpu(cpu, &d->cpu_mask);
> > - if (r->cache.arch_has_per_cpu_cfg)
> > - rdt_domain_reconfigure_cdp(r);
> > - return;
> > - }
> > -
> > - hw_dom = kzalloc_node(sizeof(*hw_dom), GFP_KERNEL, cpu_to_node(cpu));
> > - if (!hw_dom)
> > - return;
> > -
> > - d = &hw_dom->d_resctrl;
> > - d->id = id;
> > - cpumask_set_cpu(cpu, &d->cpu_mask);
> > -
> > - rdt_domain_reconfigure_cdp(r);
> > -
> > - if (r->alloc_capable && domain_setup_ctrlval(r, d)) {
> > - domain_free(hw_dom);
> > - return;
> > - }
> > -
> > - if (r->mon_capable && arch_domain_mbm_alloc(r->num_rmid, hw_dom)) {
> > - domain_free(hw_dom);
> > - return;
> > - }
> > -
> > - list_add_tail(&d->list, add_pos);
> > -
> > - err = resctrl_online_domain(r, d);
> > - if (err) {
> > - list_del(&d->list);
> > - domain_free(hw_dom);
> > - }
> > + if (r->alloc_capable)
> > + domain_add_cpu_ctrl(cpu, r);
> > + if (r->mon_capable)
> > + domain_add_cpu_mon(cpu, r);
> > }
> >
> > -static void domain_remove_cpu(int cpu, struct rdt_resource *r)
> > +static void domain_remove_cpu_ctrl(int cpu, struct rdt_resource *r)
> > {
> > - int id = get_domain_id_from_scope(cpu, r->scope);
> > + int id = get_domain_id_from_scope(cpu, r->ctrl_scope);
> > struct rdt_hw_domain *hw_dom;
> > struct rdt_domain *d;
> >
> > - d = rdt_find_domain(r, id, NULL);
> > + d = rdt_find_ctrldomain(&r->domains, id, NULL);
> > if (IS_ERR_OR_NULL(d)) {
> > - pr_warn("Couldn't find cache id for CPU %d\n", cpu);
> > + pr_warn("Couldn't find scope id=%d for CPU %d\n", id, cpu);
> > return;
> > }
> > hw_dom = resctrl_to_arch_dom(d);
> >
> > cpumask_clear_cpu(cpu, &d->cpu_mask);
> > if (cpumask_empty(&d->cpu_mask)) {
> > - resctrl_offline_domain(r, d);
> > + resctrl_offline_ctrl_domain(r, d);
> > list_del(&d->list);
> >
> > /*
> > @@ -593,6 +658,30 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
> >
> > return;
> > }
> > +}
> > +
> > +static void domain_remove_cpu_mon(int cpu, struct rdt_resource *r)
> > +{
> > + int id = get_domain_id_from_scope(cpu, r->mon_scope);
> > + struct rdt_hw_domain *hw_mondom;
> > + struct rdt_domain *d;
> > +
> > + d = rdt_find_mondomain(&r->mondomains, id, NULL);
> > + if (IS_ERR_OR_NULL(d)) {
> > + pr_warn("Couldn't find scope id=%d for CPU %d\n", id, cpu);
> > + return;
> > + }
> > + hw_mondom = resctrl_to_arch_dom(d);
> > +
> > + cpumask_clear_cpu(cpu, &d->cpu_mask);
> > + if (cpumask_empty(&d->cpu_mask)) {
> > + resctrl_offline_mon_domain(r, d);
> > + list_del(&d->list);
> > +
>
> This is an awkward empty line.
Deleted it.
>
> > + mondomain_free(hw_mondom);
> > +
> > + return;
> > + }
> >
> > if (r == &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl) {
> > if (is_mbm_enabled() && cpu == d->mbm_work_cpu) {
>
> ...
>
> Reinette