Messages in this thread Patch in this message | | | From | Mike Tipton <> | Subject | [PATCH] interconnect: Replace mutex with rt_mutex | Date | Tue, 6 Sep 2022 12:14:23 -0700 |
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Replace mutex with rt_mutex to prevent priority inversion between clients, which can cause unacceptable delays in some cases.
Signed-off-by: Mike Tipton <quic_mdtipton@quicinc.com> ---
We've run into a number of cases internally and from customers where high priority, RT clients (typically display) become blocked for long periods of time on lower priority, non-RT clients. Switching to rt_mutex has proven to help performance in these cases.
drivers/interconnect/core.c | 80 ++++++++++++++++++------------------- 1 file changed, 40 insertions(+), 40 deletions(-)
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c index 25debded65a8..a536c013d9ca 100644 --- a/drivers/interconnect/core.c +++ b/drivers/interconnect/core.c @@ -14,7 +14,7 @@ #include <linux/interconnect-provider.h> #include <linux/list.h> #include <linux/module.h> -#include <linux/mutex.h> +#include <linux/rtmutex.h> #include <linux/slab.h> #include <linux/of.h> #include <linux/overflow.h> @@ -28,7 +28,7 @@ static DEFINE_IDR(icc_idr); static LIST_HEAD(icc_providers); static int providers_count; static bool synced_state; -static DEFINE_MUTEX(icc_lock); +static DEFINE_RT_MUTEX(icc_lock); static struct dentry *icc_debugfs_dir; static void icc_summary_show_one(struct seq_file *s, struct icc_node *n) @@ -47,7 +47,7 @@ static int icc_summary_show(struct seq_file *s, void *data) seq_puts(s, " node tag avg peak\n"); seq_puts(s, "--------------------------------------------------------------------\n"); - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); list_for_each_entry(provider, &icc_providers, provider_list) { struct icc_node *n; @@ -73,7 +73,7 @@ static int icc_summary_show(struct seq_file *s, void *data) } } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return 0; } @@ -104,7 +104,7 @@ static int icc_graph_show(struct seq_file *s, void *data) int i; seq_puts(s, "digraph {\n\trankdir = LR\n\tnode [shape = record]\n"); - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); /* draw providers as cluster subgraphs */ cluster_index = 0; @@ -136,7 +136,7 @@ static int icc_graph_show(struct seq_file *s, void *data) icc_graph_show_link(s, 1, n, n->links[i]); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); seq_puts(s, "}"); return 0; @@ -362,7 +362,7 @@ struct icc_node_data *of_icc_get_from_provider(struct of_phandle_args *spec) if (!spec) return ERR_PTR(-EINVAL); - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); list_for_each_entry(provider, &icc_providers, provider_list) { if (provider->dev->of_node == spec->np) { if (provider->xlate_extended) { @@ -378,7 +378,7 @@ struct icc_node_data *of_icc_get_from_provider(struct of_phandle_args *spec) } } } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); if (IS_ERR(node)) return ERR_CAST(node); @@ -490,9 +490,9 @@ struct icc_path *of_icc_get_by_index(struct device *dev, int idx) return ERR_CAST(dst_data); } - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); path = path_find(dev, src_data->node, dst_data->node); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); if (IS_ERR(path)) { dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path)); goto free_icc_data; @@ -577,12 +577,12 @@ void icc_set_tag(struct icc_path *path, u32 tag) if (!path) return; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); for (i = 0; i < path->num_nodes; i++) path->reqs[i].tag = tag; - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); } EXPORT_SYMBOL_GPL(icc_set_tag); @@ -632,7 +632,7 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw) if (WARN_ON(IS_ERR(path) || !path->num_nodes)) return -EINVAL; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); old_avg = path->reqs[0].avg_bw; old_peak = path->reqs[0].peak_bw; @@ -664,7 +664,7 @@ int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw) apply_constraints(path); } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); trace_icc_set_bw_end(path, ret); @@ -682,12 +682,12 @@ static int __icc_enable(struct icc_path *path, bool enable) if (WARN_ON(IS_ERR(path) || !path->num_nodes)) return -EINVAL; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); for (i = 0; i < path->num_nodes; i++) path->reqs[i].enabled = enable; - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return icc_set_bw(path, path->reqs[0].avg_bw, path->reqs[0].peak_bw); @@ -726,7 +726,7 @@ struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id) struct icc_node *src, *dst; struct icc_path *path = ERR_PTR(-EPROBE_DEFER); - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); src = node_find(src_id); if (!src) @@ -748,7 +748,7 @@ struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id) path = ERR_PTR(-ENOMEM); } out: - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return path; } EXPORT_SYMBOL_GPL(icc_get); @@ -773,14 +773,14 @@ void icc_put(struct icc_path *path) if (ret) pr_err("%s: error (%d)\n", __func__, ret); - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); for (i = 0; i < path->num_nodes; i++) { node = path->reqs[i].node; hlist_del(&path->reqs[i].req_node); if (!WARN_ON(!node->provider->users)) node->provider->users--; } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); kfree_const(path->name); kfree(path); @@ -822,11 +822,11 @@ struct icc_node *icc_node_create(int id) { struct icc_node *node; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); node = icc_node_create_nolock(id); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return node; } @@ -840,7 +840,7 @@ void icc_node_destroy(int id) { struct icc_node *node; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); node = node_find(id); if (node) { @@ -848,7 +848,7 @@ void icc_node_destroy(int id) WARN_ON(!hlist_empty(&node->req_list)); } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); kfree(node); } @@ -876,7 +876,7 @@ int icc_link_create(struct icc_node *node, const int dst_id) if (!node->provider) return -EINVAL; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); dst = node_find(dst_id); if (!dst) { @@ -900,7 +900,7 @@ int icc_link_create(struct icc_node *node, const int dst_id) node->links[node->num_links++] = dst; out: - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return ret; } @@ -925,7 +925,7 @@ int icc_link_destroy(struct icc_node *src, struct icc_node *dst) if (IS_ERR_OR_NULL(dst)) return -EINVAL; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); for (slot = 0; slot < src->num_links; slot++) if (src->links[slot] == dst) @@ -946,7 +946,7 @@ int icc_link_destroy(struct icc_node *src, struct icc_node *dst) ret = -ENOMEM; out: - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return ret; } @@ -962,7 +962,7 @@ void icc_node_add(struct icc_node *node, struct icc_provider *provider) if (WARN_ON(node->provider)) return; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); node->provider = provider; list_add_tail(&node->node_list, &provider->nodes); @@ -988,7 +988,7 @@ void icc_node_add(struct icc_node *node, struct icc_provider *provider) node->avg_bw = 0; node->peak_bw = 0; - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); } EXPORT_SYMBOL_GPL(icc_node_add); @@ -998,11 +998,11 @@ EXPORT_SYMBOL_GPL(icc_node_add); */ void icc_node_del(struct icc_node *node) { - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); list_del(&node->node_list); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); } EXPORT_SYMBOL_GPL(icc_node_del); @@ -1041,12 +1041,12 @@ int icc_provider_add(struct icc_provider *provider) if (WARN_ON(!provider->xlate && !provider->xlate_extended)) return -EINVAL; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); INIT_LIST_HEAD(&provider->nodes); list_add_tail(&provider->provider_list, &icc_providers); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); dev_dbg(provider->dev, "interconnect provider added to topology\n"); @@ -1060,22 +1060,22 @@ EXPORT_SYMBOL_GPL(icc_provider_add); */ void icc_provider_del(struct icc_provider *provider) { - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); if (provider->users) { pr_warn("interconnect provider still has %d users\n", provider->users); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return; } if (!list_empty(&provider->nodes)) { pr_warn("interconnect provider still has nodes\n"); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); return; } list_del(&provider->provider_list); - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); } EXPORT_SYMBOL_GPL(icc_provider_del); @@ -1110,7 +1110,7 @@ void icc_sync_state(struct device *dev) if (count < providers_count) return; - mutex_lock(&icc_lock); + rt_mutex_lock(&icc_lock); synced_state = true; list_for_each_entry(p, &icc_providers, provider_list) { dev_dbg(p->dev, "interconnect provider is in synced state\n"); @@ -1123,7 +1123,7 @@ void icc_sync_state(struct device *dev) } } } - mutex_unlock(&icc_lock); + rt_mutex_unlock(&icc_lock); } EXPORT_SYMBOL_GPL(icc_sync_state); -- 2.17.1
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