From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/... --------------------------- When resctrl wants to read a domain's 'QOS_L3_OCCUP', it needs to allocate a monitor on the corresponding resource. Monitors are allocated by class instead of component. Add helpers to do this. The MBM events depend on having their monitors allocated at init time so that they can be left running. The value USE_RMID_IDX is out of range for a monitor, and is used to indicate this behaviour. resctrl_arch_mon_ctx_alloc() is implemented to have a no_wait version and a waitqueue for callers that sleep. The no_wait version will later become an interface for the resctrl_pmu to use. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/platform/mpam/mpam_internal.h | 3 ++ drivers/platform/mpam/mpam_resctrl.c | 72 +++++++++++++++++++++++++++ include/linux/arm_mpam.h | 4 ++ 3 files changed, 79 insertions(+) diff --git a/drivers/platform/mpam/mpam_internal.h b/drivers/platform/mpam/mpam_internal.h index 49fc264d32f7..4d982469b9f5 100644 --- a/drivers/platform/mpam/mpam_internal.h +++ b/drivers/platform/mpam/mpam_internal.h @@ -17,6 +17,9 @@ DECLARE_STATIC_KEY_FALSE(mpam_enabled); +/* Value to indicate the allocated monitor is derived from the RMID index. */ +#define USE_RMID_IDX (U16_MAX + 1) + static inline bool mpam_is_enabled(void) { return static_branch_likely(&mpam_enabled); diff --git a/drivers/platform/mpam/mpam_resctrl.c b/drivers/platform/mpam/mpam_resctrl.c index 19916d9149c5..70b1879de10a 100644 --- a/drivers/platform/mpam/mpam_resctrl.c +++ b/drivers/platform/mpam/mpam_resctrl.c @@ -22,6 +22,8 @@ u64 mpam_resctrl_default_group; +DECLARE_WAIT_QUEUE_HEAD(resctrl_mon_ctx_waiters); + /* * The classes we've picked to map to resctrl resources. * Class pointer may be NULL. @@ -39,6 +41,10 @@ static struct mpam_class *mbm_total_class; */ static bool cdp_enabled; +/* A dummy mon context to use when the monitors were allocated up front */ +u32 __mon_is_rmid_idx = USE_RMID_IDX; +void *mon_is_rmid_idx = &__mon_is_rmid_idx; + bool resctrl_arch_alloc_capable(void) { return exposed_alloc_capable; @@ -232,6 +238,72 @@ struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l) return &mpam_resctrl_exports[l].resctrl_res; } +static void *resctrl_arch_mon_ctx_alloc_no_wait(struct rdt_resource *r, + int evtid) +{ + struct mpam_resctrl_res *res; + u32 *ret = kmalloc(sizeof(*ret), GFP_KERNEL); + + if (!ret) + return ERR_PTR(-ENOMEM); + + switch (evtid) { + case QOS_L3_OCCUP_EVENT_ID: + res = container_of(r, struct mpam_resctrl_res, resctrl_res); + + *ret = mpam_alloc_csu_mon(res->class); + return ret; + case QOS_L3_MBM_LOCAL_EVENT_ID: + case QOS_L3_MBM_TOTAL_EVENT_ID: + return mon_is_rmid_idx; + } + + return ERR_PTR(-EOPNOTSUPP); +} + +void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid) +{ + DEFINE_WAIT(wait); + void *ret; + + might_sleep(); + + do { + prepare_to_wait(&resctrl_mon_ctx_waiters, &wait, + TASK_INTERRUPTIBLE); + ret = resctrl_arch_mon_ctx_alloc_no_wait(r, evtid); + if (PTR_ERR(ret) == -ENOSPC) + schedule(); + } while (PTR_ERR(ret) == -ENOSPC && !signal_pending(current)); + finish_wait(&resctrl_mon_ctx_waiters, &wait); + + return ret; +} + +void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid, + void *arch_mon_ctx) +{ + struct mpam_resctrl_res *res; + u32 mon = *(u32 *)arch_mon_ctx; + + if (mon == USE_RMID_IDX) + return; + kfree(arch_mon_ctx); + arch_mon_ctx = NULL; + + res = container_of(r, struct mpam_resctrl_res, resctrl_res); + + switch (evtid) { + case QOS_L3_OCCUP_EVENT_ID: + mpam_free_csu_mon(res->class, mon); + wake_up(&resctrl_mon_ctx_waiters); + return; + case QOS_L3_MBM_TOTAL_EVENT_ID: + case QOS_L3_MBM_LOCAL_EVENT_ID: + return; + } +} + static bool cache_has_usable_cpor(struct mpam_class *class) { struct mpam_props *cprops = &class->props; diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h index 94179b86a9e6..7206a35bb205 100644 --- a/include/linux/arm_mpam.h +++ b/include/linux/arm_mpam.h @@ -72,4 +72,8 @@ u32 resctrl_arch_rmid_idx_encode(u32 closid, u32 rmid); void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid); u32 resctrl_arch_system_num_rmid_idx(void); +struct rdt_resource; +void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid); +void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid, void *ctx); + #endif /* __LINUX_ARM_MPAM_H */ -- 2.25.1