Re: [PATCH v4 02/24] x86/resctrl: Split struct rdt_domain

[Babu Moger]

On 6/14/21 3:09 PM, James Morse wrote:
> resctrl is the defacto Linux ABI for SoC resource partitioning features.
> 
> To support it on another architecture, it needs to be abstracted from
> the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
> struct rdt_resource contains a mix of architecture private details
> and properties of the filesystem interface user-space users.
> 
> Continue by splitting struct rdt_domain, into an architecture private
> 'hw' struct, which contains the common resctrl structure that would be
> used by any architecture. The hardware values in ctrl_val and mbps_val
> need to be accessed via helpers to allow another architecture to convert
> these into a different format if necessary. After this split, filesystem
> code paths touching a 'hw' struct indicates where an abstraction
> is needed.
> 
> Splitting this structure only moves types around, and should not lead
> to any change in behaviour.
> 
> Reviewed-by: Jamie Iles <jamie@xxxxxxxxxxxx>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
> ---
> Changes since v3:
>  * Removed a double word, removed a space.
> 
> Changes since v2:
>  * Shuffled commit message,
>  * Changed kerneldoc text above rdt_hw_domain
> 
> Changes since v1:
>  * Tabs space and other whitespace
>  * cpu becomes CPU in all comments touched
> ---
>  arch/x86/kernel/cpu/resctrl/core.c        | 32 ++++++++++-------
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 10 ++++--
>  arch/x86/kernel/cpu/resctrl/internal.h    | 43 +++++++----------------
>  arch/x86/kernel/cpu/resctrl/monitor.c     |  8 +++--
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 29 +++++++++------
>  include/linux/resctrl.h                   | 32 ++++++++++++++++-
>  6 files changed, 94 insertions(+), 60 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 415d0f04efd7..aff5d0dde6c1 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -385,10 +385,11 @@ static void
>  mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
>  {
>  	unsigned int i;
> +	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>  
>  	for (i = m->low; i < m->high; i++)
> -		wrmsrl(hw_res->msr_base + i, d->ctrl_val[i]);
> +		wrmsrl(hw_res->msr_base + i, hw_dom->ctrl_val[i]);
>  }
>  
>  /*
> @@ -410,21 +411,23 @@ mba_wrmsr_intel(struct rdt_domain *d, struct msr_param *m,
>  		struct rdt_resource *r)
>  {
>  	unsigned int i;
> +	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>  
>  	/*  Write the delay values for mba. */
>  	for (i = m->low; i < m->high; i++)
> -		wrmsrl(hw_res->msr_base + i, delay_bw_map(d->ctrl_val[i], r));
> +		wrmsrl(hw_res->msr_base + i, delay_bw_map(hw_dom->ctrl_val[i], r));
>  }
>  
>  static void
>  cat_wrmsr(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
>  {
>  	unsigned int i;
> +	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>  
>  	for (i = m->low; i < m->high; i++)
> -		wrmsrl(hw_res->msr_base + cbm_idx(r, i), d->ctrl_val[i]);
> +		wrmsrl(hw_res->msr_base + cbm_idx(r, i), hw_dom->ctrl_val[i]);
>  }
>  
>  struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r)
> @@ -510,21 +513,22 @@ void setup_default_ctrlval(struct rdt_resource *r, u32 *dc, u32 *dm)
>  static int domain_setup_ctrlval(struct rdt_resource *r, struct rdt_domain *d)
>  {
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> +	struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
>  	struct msr_param m;
>  	u32 *dc, *dm;
>  
> -	dc = kmalloc_array(hw_res->num_closid, sizeof(*d->ctrl_val), GFP_KERNEL);
> +	dc = kmalloc_array(hw_res->num_closid, sizeof(*hw_dom->ctrl_val), GFP_KERNEL);
>  	if (!dc)
>  		return -ENOMEM;
>  
> -	dm = kmalloc_array(hw_res->num_closid, sizeof(*d->mbps_val), GFP_KERNEL);
> +	dm = kmalloc_array(hw_res->num_closid, sizeof(*hw_dom->mbps_val), GFP_KERNEL);
>  	if (!dm) {
>  		kfree(dc);
>  		return -ENOMEM;
>  	}
>  
> -	d->ctrl_val = dc;
> -	d->mbps_val = dm;
> +	hw_dom->ctrl_val = dc;
> +	hw_dom->mbps_val = dm;
>  	setup_default_ctrlval(r, dc, dm);
>  
>  	m.low = 0;
> @@ -586,6 +590,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  {
>  	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
>  	struct list_head *add_pos = NULL;
> +	struct rdt_hw_domain *hw_dom;
>  	struct rdt_domain *d;
>  
>  	d = rdt_find_domain(r, id, &add_pos);
> @@ -601,10 +606,11 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  		return;
>  	}
>  
> -	d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
> -	if (!d)
> +	hw_dom = kzalloc_node(sizeof(*hw_dom), GFP_KERNEL, cpu_to_node(cpu));
> +	if (!hw_dom)
>  		return;
>  
> +	d = &hw_dom->resctrl;
>  	d->id = id;
>  	cpumask_set_cpu(cpu, &d->cpu_mask);
>  
> @@ -633,6 +639,7 @@ static void domain_add_cpu(int cpu, struct rdt_resource *r)
>  static void domain_remove_cpu(int cpu, struct rdt_resource *r)
>  {
>  	int id = get_cpu_cacheinfo_id(cpu, r->cache_level);
> +	struct rdt_hw_domain *hw_dom;
>  	struct rdt_domain *d;
>  
>  	d = rdt_find_domain(r, id, NULL);
> @@ -640,6 +647,7 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
>  		pr_warn("Couldn't find cache id for CPU %d\n", cpu);
>  		return;
>  	}
> +	hw_dom = resctrl_to_arch_dom(d);
>  
>  	cpumask_clear_cpu(cpu, &d->cpu_mask);
>  	if (cpumask_empty(&d->cpu_mask)) {
> @@ -672,12 +680,12 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
>  		if (d->plr)
>  			d->plr->d = NULL;
>  
> -		kfree(d->ctrl_val);
> -		kfree(d->mbps_val);
> +		kfree(hw_dom->ctrl_val);
> +		kfree(hw_dom->mbps_val);
>  		bitmap_free(d->rmid_busy_llc);
>  		kfree(d->mbm_total);
>  		kfree(d->mbm_local);
> -		kfree(d);
> +		kfree(hw_dom);
>  		return;
>  	}
>  
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index ab6e584c9d2d..2e7466659af3 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -238,6 +238,7 @@ static int parse_line(char *line, struct rdt_resource *r,
>  
>  int update_domains(struct rdt_resource *r, int closid)
>  {
> +	struct rdt_hw_domain *hw_dom;
>  	struct msr_param msr_param;
>  	cpumask_var_t cpu_mask;
>  	struct rdt_domain *d;
> @@ -254,7 +255,8 @@ int update_domains(struct rdt_resource *r, int closid)
>  
>  	mba_sc = is_mba_sc(r);
>  	list_for_each_entry(d, &r->domains, list) {
> -		dc = !mba_sc ? d->ctrl_val : d->mbps_val;
> +		hw_dom = resctrl_to_arch_dom(d);
> +		dc = !mba_sc ? hw_dom->ctrl_val : hw_dom->mbps_val;
>  		if (d->have_new_ctrl && d->new_ctrl != dc[closid]) {
>  			cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
>  			dc[closid] = d->new_ctrl;
> @@ -375,17 +377,19 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
>  
>  static void show_doms(struct seq_file *s, struct rdt_resource *r, int closid)
>  {
> +	struct rdt_hw_domain *hw_dom;
>  	struct rdt_domain *dom;
>  	bool sep = false;
>  	u32 ctrl_val;
>  
>  	seq_printf(s, "%*s:", max_name_width, r->name);
>  	list_for_each_entry(dom, &r->domains, list) {
> +		hw_dom = resctrl_to_arch_dom(dom);
>  		if (sep)
>  			seq_puts(s, ";");
>  
> -		ctrl_val = (!is_mba_sc(r) ? dom->ctrl_val[closid] :
> -			    dom->mbps_val[closid]);
> +		ctrl_val = (!is_mba_sc(r) ? hw_dom->ctrl_val[closid] :
> +			    hw_dom->mbps_val[closid]);
>  		seq_printf(s, r->format_str, dom->id, max_data_width,
>  			   ctrl_val);
>  		sep = true;
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 43c8cf6b2b12..235cf621c878 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -299,44 +299,25 @@ struct mbm_state {
>  };
>  
>  /**
> - * struct rdt_domain - group of cpus sharing an RDT resource
> - * @list:	all instances of this resource
> - * @id:		unique id for this instance
> - * @cpu_mask:	which cpus share this resource
> - * @rmid_busy_llc:
> - *		bitmap of which limbo RMIDs are above threshold
> - * @mbm_total:	saved state for MBM total bandwidth
> - * @mbm_local:	saved state for MBM local bandwidth
> - * @mbm_over:	worker to periodically read MBM h/w counters
> - * @cqm_limbo:	worker to periodically read CQM h/w counters
> - * @mbm_work_cpu:
> - *		worker cpu for MBM h/w counters
> - * @cqm_work_cpu:
> - *		worker cpu for CQM h/w counters
> + * struct rdt_hw_domain - Arch private attributes of a set of CPUs that share
> + *			  a resource
> + * @resctrl:	Properties exposed to the resctrl file system
>   * @ctrl_val:	array of cache or mem ctrl values (indexed by CLOSID)
>   * @mbps_val:	When mba_sc is enabled, this holds the bandwidth in MBps
> - * @new_ctrl:	new ctrl value to be loaded
> - * @have_new_ctrl: did user provide new_ctrl for this domain
> - * @plr:	pseudo-locked region (if any) associated with domain
> + *
> + * Members of this structure are accessed via helpers that provide abstraction.
>   */
> -struct rdt_domain {
> -	struct list_head		list;
> -	int				id;
> -	struct cpumask			cpu_mask;
> -	unsigned long			*rmid_busy_llc;
> -	struct mbm_state		*mbm_total;
> -	struct mbm_state		*mbm_local;
> -	struct delayed_work		mbm_over;
> -	struct delayed_work		cqm_limbo;
> -	int				mbm_work_cpu;
> -	int				cqm_work_cpu;
> +struct rdt_hw_domain {
> +	struct rdt_domain		resctrl;

Naming is bit confusing here. There is another field with the same
name(patch1).

+struct rdt_hw_resource {
+	struct rdt_resource	resctrl;

I think we should make this bit more clearer. May be or something similar.

struct rdt_hw_domain {
    struct rdt_domain		d_resctrl;

>  	u32				*ctrl_val;
>  	u32				*mbps_val;
> -	u32				new_ctrl;
> -	bool				have_new_ctrl;
> -	struct pseudo_lock_region	*plr;
>  };
>  
> +static inline struct rdt_hw_domain *resctrl_to_arch_dom(struct rdt_domain *r)
> +{
> +	return container_of(r, struct rdt_hw_domain, resctrl);
> +}
> +
>  /**
>   * struct msr_param - set a range of MSRs from a domain
>   * @res:       The resource to use
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 685e7f86d908..76eea10f2e2c 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -418,6 +418,7 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
>  	u32 closid, rmid, cur_msr, cur_msr_val, new_msr_val;
>  	struct mbm_state *pmbm_data, *cmbm_data;
>  	struct rdt_hw_resource *hw_r_mba;
> +	struct rdt_hw_domain *hw_dom_mba;
>  	u32 cur_bw, delta_bw, user_bw;
>  	struct rdt_resource *r_mba;
>  	struct rdt_domain *dom_mba;
> @@ -438,11 +439,12 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
>  		pr_warn_once("Failure to get domain for MBA update\n");
>  		return;
>  	}
> +	hw_dom_mba = resctrl_to_arch_dom(dom_mba);
>  
>  	cur_bw = pmbm_data->prev_bw;
> -	user_bw = dom_mba->mbps_val[closid];
> +	user_bw = hw_dom_mba->mbps_val[closid];
>  	delta_bw = pmbm_data->delta_bw;
> -	cur_msr_val = dom_mba->ctrl_val[closid];
> +	cur_msr_val = hw_dom_mba->ctrl_val[closid];
>  
>  	/*
>  	 * For Ctrl groups read data from child monitor groups.
> @@ -479,7 +481,7 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
>  
>  	cur_msr = hw_r_mba->msr_base + closid;
>  	wrmsrl(cur_msr, delay_bw_map(new_msr_val, r_mba));
> -	dom_mba->ctrl_val[closid] = new_msr_val;
> +	hw_dom_mba->ctrl_val[closid] = new_msr_val;
>  
>  	/*
>  	 * Delta values are updated dynamically package wise for each
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index 5126a1e58d97..9a8665c8ab89 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -915,7 +915,7 @@ static int rdt_bit_usage_show(struct kernfs_open_file *of,
>  	list_for_each_entry(dom, &r->domains, list) {
>  		if (sep)
>  			seq_putc(seq, ';');
> -		ctrl = dom->ctrl_val;
> +		ctrl = resctrl_to_arch_dom(dom)->ctrl_val;
>  		sw_shareable = 0;
>  		exclusive = 0;
>  		seq_printf(seq, "%d=", dom->id);
> @@ -1193,7 +1193,7 @@ static bool __rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d
>  	}
>  
>  	/* Check for overlap with other resource groups */
> -	ctrl = d->ctrl_val;
> +	ctrl = resctrl_to_arch_dom(d)->ctrl_val;
>  	for (i = 0; i < closids_supported(); i++, ctrl++) {
>  		ctrl_b = *ctrl;
>  		mode = rdtgroup_mode_by_closid(i);
> @@ -1262,6 +1262,7 @@ bool rdtgroup_cbm_overlaps(struct rdt_resource *r, struct rdt_domain *d,
>   */
>  static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
>  {
> +	struct rdt_hw_domain *hw_dom;
>  	int closid = rdtgrp->closid;
>  	struct rdt_resource *r;
>  	bool has_cache = false;
> @@ -1272,7 +1273,8 @@ static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
>  			continue;
>  		has_cache = true;
>  		list_for_each_entry(d, &r->domains, list) {
> -			if (rdtgroup_cbm_overlaps(r, d, d->ctrl_val[closid],
> +			hw_dom = resctrl_to_arch_dom(d);
> +			if (rdtgroup_cbm_overlaps(r, d, hw_dom->ctrl_val[closid],
>  						  rdtgrp->closid, false)) {
>  				rdt_last_cmd_puts("Schemata overlaps\n");
>  				return false;
> @@ -1404,6 +1406,7 @@ unsigned int rdtgroup_cbm_to_size(struct rdt_resource *r,
>  static int rdtgroup_size_show(struct kernfs_open_file *of,
>  			      struct seq_file *s, void *v)
>  {
> +	struct rdt_hw_domain *hw_dom;
>  	struct rdtgroup *rdtgrp;
>  	struct rdt_resource *r;
>  	struct rdt_domain *d;
> @@ -1438,14 +1441,15 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
>  		sep = false;
>  		seq_printf(s, "%*s:", max_name_width, r->name);
>  		list_for_each_entry(d, &r->domains, list) {
> +			hw_dom = resctrl_to_arch_dom(d);
>  			if (sep)
>  				seq_putc(s, ';');
>  			if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP) {
>  				size = 0;
>  			} else {
>  				ctrl = (!is_mba_sc(r) ?
> -						d->ctrl_val[rdtgrp->closid] :
> -						d->mbps_val[rdtgrp->closid]);
> +						hw_dom->ctrl_val[rdtgrp->closid] :
> +						hw_dom->mbps_val[rdtgrp->closid]);
>  				if (r->rid == RDT_RESOURCE_MBA)
>  					size = ctrl;
>  				else
> @@ -1940,6 +1944,7 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r)
>  static int set_mba_sc(bool mba_sc)
>  {
>  	struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_MBA].resctrl;
> +	struct rdt_hw_domain *hw_dom;
>  	struct rdt_domain *d;
>  
>  	if (!is_mbm_enabled() || !is_mba_linear() ||
> @@ -1947,8 +1952,10 @@ static int set_mba_sc(bool mba_sc)
>  		return -EINVAL;
>  
>  	r->membw.mba_sc = mba_sc;
> -	list_for_each_entry(d, &r->domains, list)
> -		setup_default_ctrlval(r, d->ctrl_val, d->mbps_val);
> +	list_for_each_entry(d, &r->domains, list) {
> +		hw_dom = resctrl_to_arch_dom(d);
> +		setup_default_ctrlval(r, hw_dom->ctrl_val, hw_dom->mbps_val);
> +	}
>  
>  	return 0;
>  }
> @@ -2265,6 +2272,7 @@ static int rdt_init_fs_context(struct fs_context *fc)
>  static int reset_all_ctrls(struct rdt_resource *r)
>  {
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> +	struct rdt_hw_domain *hw_dom;
>  	struct msr_param msr_param;
>  	cpumask_var_t cpu_mask;
>  	struct rdt_domain *d;
> @@ -2283,10 +2291,11 @@ static int reset_all_ctrls(struct rdt_resource *r)
>  	 * from each domain to update the MSRs below.
>  	 */
>  	list_for_each_entry(d, &r->domains, list) {
> +		hw_dom = resctrl_to_arch_dom(d);
>  		cpumask_set_cpu(cpumask_any(&d->cpu_mask), cpu_mask);
>  
>  		for (i = 0; i < hw_res->num_closid; i++)
> -			d->ctrl_val[i] = r->default_ctrl;
> +			hw_dom->ctrl_val[i] = r->default_ctrl;
>  	}
>  	cpu = get_cpu();
>  	/* Update CBM on this cpu if it's in cpu_mask. */
> @@ -2665,7 +2674,7 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
>  	d->have_new_ctrl = false;
>  	d->new_ctrl = r->cache.shareable_bits;
>  	used_b = r->cache.shareable_bits;
> -	ctrl = d->ctrl_val;
> +	ctrl = resctrl_to_arch_dom(d)->ctrl_val;
>  	for (i = 0; i < closids_supported(); i++, ctrl++) {
>  		if (closid_allocated(i) && i != closid) {
>  			mode = rdtgroup_mode_by_closid(i);
> @@ -2682,7 +2691,7 @@ static int __init_one_rdt_domain(struct rdt_domain *d, struct rdt_resource *r,
>  			 * with an exclusive group.
>  			 */
>  			if (d_cdp)
> -				peer_ctl = d_cdp->ctrl_val[i];
> +				peer_ctl = resctrl_to_arch_dom(d_cdp)->ctrl_val[i];
>  			else
>  				peer_ctl = 0;
>  			used_b |= *ctrl | peer_ctl;
> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
> index ee92df9c7252..be6f5df78e31 100644
> --- a/include/linux/resctrl.h
> +++ b/include/linux/resctrl.h
> @@ -15,7 +15,37 @@ int proc_resctrl_show(struct seq_file *m,
>  
>  #endif
>  
> -struct rdt_domain;
> +/**
> + * struct rdt_domain - group of CPUs sharing a resctrl resource
> + * @list:		all instances of this resource
> + * @id:			unique id for this instance
> + * @cpu_mask:		which CPUs share this resource
> + * @new_ctrl:		new ctrl value to be loaded
> + * @have_new_ctrl:	did user provide new_ctrl for this domain
> + * @rmid_busy_llc:	bitmap of which limbo RMIDs are above threshold
> + * @mbm_total:		saved state for MBM total bandwidth
> + * @mbm_local:		saved state for MBM local bandwidth
> + * @mbm_over:		worker to periodically read MBM h/w counters
> + * @cqm_limbo:		worker to periodically read CQM h/w counters
> + * @mbm_work_cpu:	worker CPU for MBM h/w counters
> + * @cqm_work_cpu:	worker CPU for CQM h/w counters
> + * @plr:		pseudo-locked region (if any) associated with domain
> + */
> +struct rdt_domain {
> +	struct list_head		list;
> +	int				id;
> +	struct cpumask			cpu_mask;
> +	u32				new_ctrl;
> +	bool				have_new_ctrl;
> +	unsigned long			*rmid_busy_llc;
> +	struct mbm_state		*mbm_total;
> +	struct mbm_state		*mbm_local;
> +	struct delayed_work		mbm_over;
> +	struct delayed_work		cqm_limbo;
> +	int				mbm_work_cpu;
> +	int				cqm_work_cpu;
> +	struct pseudo_lock_region	*plr;
> +};
>  
>  /**
>   * struct resctrl_cache - Cache allocation related data
>