Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v2 06/18] x86/resctrl: Allow the allocator to check if a CLOSID can allocate clean RMID | Date | Fri, 13 Jan 2023 17:54:47 +0000 |
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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.
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> Signed-off-by: James Morse <james.morse@arm.com>
--- Changes since v1: * Removed superflous IS_ENABLED(). --- arch/x86/kernel/cpu/resctrl/internal.h | 1 + arch/x86/kernel/cpu/resctrl/monitor.c | 31 ++++++++++++++++++++++++++ arch/x86/kernel/cpu/resctrl/rdtgroup.c | 17 ++++++++------ 3 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 013c8fc9fd28..adae6231324f 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -509,6 +509,7 @@ 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 347be3767241..190ac183139e 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -327,6 +327,37 @@ 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..e1f879e13823 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 +119,17 @@ 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 (resctrl_closid_is_dirty(closid)) + 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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