Messages in this thread | | | Date | Thu, 9 Nov 2023 14:39:16 -0600 | From | "Moger, Babu" <> | Subject | Re: [PATCH v7 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid |
| |
Hi James,
On 10/25/23 13:03, James Morse wrote: > 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. > > Instead of allocating the first free CLOSID, on architectures where > CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is enabled, search > closid_num_dirty_rmid[] to find the cleanest CLOSID. > > The CLOSID found is returned to closid_alloc() for the free list > to be updated. > > Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> > Tested-by: Peter Newman <peternewman@google.com> > Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> > Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> > Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
> --- > Changes since v4: > * Dropped stale section from comment > > Changes since v5: > * Renamed some variables. > > No changes since v6 > --- > arch/x86/kernel/cpu/resctrl/internal.h | 2 ++ > arch/x86/kernel/cpu/resctrl/monitor.c | 45 ++++++++++++++++++++++++++ > arch/x86/kernel/cpu/resctrl/rdtgroup.c | 19 ++++++++--- > 3 files changed, 61 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h > index 2f1d4f141dab..521afa016b05 100644 > --- a/arch/x86/kernel/cpu/resctrl/internal.h > +++ b/arch/x86/kernel/cpu/resctrl/internal.h > @@ -568,5 +568,7 @@ void rdt_domain_reconfigure_cdp(struct rdt_resource *r); > void __init thread_throttle_mode_init(void); > void __init mbm_config_rftype_init(const char *config); > void rdt_staged_configs_clear(void); > +bool closid_allocated(unsigned int closid); > +int resctrl_find_cleanest_closid(void); > > #endif /* _ASM_X86_RESCTRL_INTERNAL_H */ > diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c > index 9a07707d3eb4..cf512d4d383e 100644 > --- a/arch/x86/kernel/cpu/resctrl/monitor.c > +++ b/arch/x86/kernel/cpu/resctrl/monitor.c > @@ -386,6 +386,51 @@ static struct rmid_entry *resctrl_find_free_rmid(u32 closid) > return ERR_PTR(-ENOSPC); > } > > +/** > + * resctrl_find_cleanest_closid() - Find a CLOSID where all the associated > + * RMID are clean, or the CLOSID that has > + * the most clean RMID. > + * > + * MPAM's equivalent of RMID are per-CLOSID, meaning a freshly allocated CLOSID > + * may not be able to allocate clean RMID. To avoid this the allocator will > + * choose the CLOSID with the most clean RMID. > + * > + * When the CLOSID and RMID are independent numbers, the first free CLOSID will > + * be returned. > + */ > +int resctrl_find_cleanest_closid(void) > +{ > + u32 cleanest_closid = ~0; > + int i = 0; > + > + lockdep_assert_held(&rdtgroup_mutex); > + > + if (!IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) > + return -EIO; > + > + for (i = 0; i < closids_supported(); i++) { > + int num_dirty; > + > + if (closid_allocated(i)) > + continue; > + > + num_dirty = closid_num_dirty_rmid[i]; > + if (num_dirty == 0) > + return i; > + > + if (cleanest_closid == ~0) > + cleanest_closid = i; > + > + if (num_dirty < closid_num_dirty_rmid[cleanest_closid]) > + cleanest_closid = i; > + } > + > + if (cleanest_closid == ~0) > + return -ENOSPC; > + > + return cleanest_closid; > +} > + > /* > * For MPAM the RMID value is not unique, and has to be considered with > * the CLOSID. The (CLOSID, RMID) pair is allocated on all domains, which > diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > index f6051a3e7262..0b9bd5f0f60d 100644 > --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c > @@ -137,13 +137,22 @@ static void closid_init(void) > > static int closid_alloc(void) > { > - u32 closid = ffs(closid_free_map); > + int cleanest_closid; > + u32 closid; > > lockdep_assert_held(&rdtgroup_mutex); > > - if (closid == 0) > - return -ENOSPC; > - closid--; > + if (IS_ENABLED(CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID)) { > + cleanest_closid = resctrl_find_cleanest_closid(); > + if (cleanest_closid < 0) > + return cleanest_closid; > + closid = cleanest_closid; > + } else { > + closid = ffs(closid_free_map); > + if (closid == 0) > + return -ENOSPC; > + closid--; > + } > __clear_bit(closid, &closid_free_map); > > return closid; > @@ -163,7 +172,7 @@ void closid_free(int closid) > * Return: true if @closid is currently associated with a resource group, > * false if @closid is free > */ > -static bool closid_allocated(unsigned int closid) > +bool closid_allocated(unsigned int closid) > { > lockdep_assert_held(&rdtgroup_mutex); >
-- Thanks Babu Moger
| |