Messages in this thread | | | From | "Shaopeng Tan (Fujitsu)" <> | Subject | RE: [PATCH 06/18] x86/resctrl: Allow the allocator to check if a CLOSID can allocate clean RMID | Date | Thu, 10 Nov 2022 10:50:43 +0000 |
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Hi James
> MPAM's PMG bits extend its PARTID space, meaning the same PMG value can > be used for different control groups. > > This means once a CLOSID is allocated, all its monitoring ids may still be dirty, > and held in limbo. > > Add a helper to allow the CLOSID allocator to check if a CLOSID has dirty RMID > values. This behaviour is enabled by a kconfig option selected by the > architecture, which avoids a pointless search for x86. > > Signed-off-by: James Morse <james.morse@arm.com> > --- > arch/x86/kernel/cpu/resctrl/internal.h | 1 + > arch/x86/kernel/cpu/resctrl/monitor.c | 31 > ++++++++++++++++++++++++++ > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 18 +++++++++------ > 3 files changed, 43 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h > b/arch/x86/kernel/cpu/resctrl/internal.h > index c8c46fe088be..faec12025a58 100644 > --- a/arch/x86/kernel/cpu/resctrl/internal.h > +++ b/arch/x86/kernel/cpu/resctrl/internal.h > @@ -519,6 +519,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup > *rdtgrp); void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp); > struct rdt_domain *get_domain_from_cpu(int cpu, struct rdt_resource *r); int > closids_supported(void); > +bool resctrl_closid_is_dirty(u32 closid); > void closid_free(int closid); > int alloc_rmid(u32 closid); > void free_rmid(u32 closid, u32 rmid); > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c > b/arch/x86/kernel/cpu/resctrl/monitor.c > index 59da256a77fe..99854ef4dee4 100644 > --- a/arch/x86/kernel/cpu/resctrl/monitor.c > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c > @@ -320,6 +320,37 @@ static struct rmid_entry *resctrl_find_free_rmid(u32 > closid) > return ERR_PTR(-ENOSPC); > } > > +/** > + * resctrl_closid_is_dirty - Determine if clean RMID can be allocate for this > + * CLOSID. > + * @closid: The CLOSID that is being queried. > + * > + * MPAM's equivalent of RMID are per-CLOSID, meaning a freshly allocate > +CLOSID > + * may not be able to allocate clean RMID. To avoid this the allocator > +will > + * only return clean CLOSID. > + */ > +bool resctrl_closid_is_dirty(u32 closid) { > + struct rmid_entry *entry; > + int i; > + > + lockdep_assert_held(&rdtgroup_mutex); > + > + if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) > + return false; > + > + for (i = 0; i < resctrl_arch_system_num_rmid_idx(); i++) { > + entry = &rmid_ptrs[i]; > + if (entry->closid != closid) > + continue; > + > + if (entry->busy) > + return true; > + } > + > + return false; > +} > + > /* > * As of now the RMIDs allocation is the same in each domain. > * However we keep track of which packages the RMIDs diff --git > a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index ac88610a6946..59f33adcf6f8 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -93,7 +93,7 @@ void rdt_last_cmd_printf(const char *fmt, ...) > * - Our choices on how to configure each resource become progressively > more > * limited as the number of resources grows. > */ > -static int closid_free_map; > +static unsigned long closid_free_map; > static int closid_free_map_len; > > int closids_supported(void) > @@ -119,14 +119,18 @@ static void closid_init(void) > > static int closid_alloc(void) > { > - u32 closid = ffs(closid_free_map); > + u32 closid; > > - if (closid == 0) > - return -ENOSPC; > - closid--; > - closid_free_map &= ~(1 << closid); > + for_each_set_bit(closid, &closid_free_map, closid_free_map_len) { > + if > (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID) && > + resctrl_closid_is_dirty(closid))
IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID) is redundant here, since it is also at the beginning of function resctrl_closid_is_dirty(closid).
Best regards, Shaopeng Tan
> + continue; > > - return closid; > + clear_bit(closid, &closid_free_map); > + return closid; > + } > + > + return -ENOSPC; > } > > void closid_free(int closid) > -- > 2.30.2
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