Hi Rob, > On May 16, 2016, at 22:37 , Rob Herring <robherring2@xxxxxxxxx> wrote: > > On Mon, May 16, 2016 at 11:52 AM, Pantelis Antoniou > <pantelis.antoniou@xxxxxxxxxxxx> wrote: >> When a device tree contains a lot of phandles, resolving one >> takes time because the original method uses a search against >> all nodes (not just the ones with phandles). >> >> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx> >> --- >> drivers/of/base.c | 41 ++++++++++++++++++++++++++++++++++++++--- >> drivers/of/dynamic.c | 8 ++++++++ >> drivers/of/of_private.h | 33 +++++++++++++++++++++++++++++++++ >> include/linux/of.h | 2 ++ >> 4 files changed, 81 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/of/base.c b/drivers/of/base.c >> index 20bbc2f..436a088 100644 >> --- a/drivers/of/base.c >> +++ b/drivers/of/base.c >> @@ -27,6 +27,7 @@ >> #include <linux/slab.h> >> #include <linux/string.h> >> #include <linux/proc_fs.h> >> +#include <linux/rhashtable.h> >> >> #include "of_private.h" >> >> @@ -41,6 +42,18 @@ static const char *of_stdout_options; >> >> struct kset *of_kset; >> >> +const struct rhashtable_params of_phandle_ht_params = { > > static > No, it won’t work. The rhashtable API requires using this at every call. >> + .key_offset = offsetof(struct device_node, phandle), /* base offset */ >> + .key_len = sizeof(phandle), >> + .head_offset = offsetof(struct device_node, ht_node), >> + .automatic_shrinking = true, >> +}; >> + >> +struct rhashtable *of_phandle_ht; >> + >> +/* default is false */ >> +bool of_phandle_ht_is_disabled; > > I think this should go. The unittest alone is not enough reason to keep. > Hmm, OK. >> + >> /* >> * Used to protect the of_aliases, to hold off addition of nodes to sysfs. >> * This mutex must be held whenever modifications are being made to the >> @@ -162,6 +175,12 @@ int __of_attach_node_post(struct device_node *np) >> struct property *pp; >> int rc; >> >> + if (of_phandle_ht_available()) { > > This can never be false as this function should only get called after init. > How about a BUG_ON() just in case something weird is going on? >> + rc = of_phandle_ht_insert(np); >> + WARN(rc, "insert to phandle hash fail @%s\n", >> + of_node_full_name(np)); >> + } >> + >> if (!IS_ENABLED(CONFIG_SYSFS)) >> return 0; >> >> @@ -194,6 +213,17 @@ void __init of_core_init(void) >> struct device_node *np; >> int ret; >> >> + of_phandle_ht = kzalloc(sizeof(*of_phandle_ht), GFP_KERNEL); >> + if (!of_phandle_ht) { >> + pr_warn("devicetree: Failed to allocate hashtable\n"); >> + return; >> + } >> + ret = rhashtable_init(of_phandle_ht, &of_phandle_ht_params); >> + if (ret) { >> + pr_warn("devicetree: Failed to initialize hashtable\n"); >> + return; >> + } >> + >> /* Create the kset, and register existing nodes */ >> mutex_lock(&of_mutex); >> of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj); >> @@ -1073,9 +1103,14 @@ struct device_node *of_find_node_by_phandle(phandle handle) >> return NULL; >> >> raw_spin_lock_irqsave(&devtree_lock, flags); >> - for_each_of_allnodes(np) >> - if (np->phandle == handle) >> - break; >> + /* when we're ready use the hash table (and not disabled) */ >> + if (of_phandle_ht_available() && !of_phandle_ht_is_disabled) > > Just "if (of_phandle_ht)” > OK >> + np = of_phandle_ht_lookup(handle); >> + else { /* fallback */ >> + for_each_of_allnodes(np) >> + if (np->phandle == handle) >> + break; >> + } >> of_node_get(np); >> raw_spin_unlock_irqrestore(&devtree_lock, flags); >> return np; >> diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c >> index 34ca783..931b905 100644 >> --- a/drivers/of/dynamic.c >> +++ b/drivers/of/dynamic.c >> @@ -11,6 +11,7 @@ >> #include <linux/slab.h> >> #include <linux/string.h> >> #include <linux/proc_fs.h> >> +#include <linux/rhashtable.h> >> >> #include "of_private.h" >> >> @@ -44,6 +45,13 @@ EXPORT_SYMBOL(of_node_put); >> void __of_detach_node_post(struct device_node *np) >> { >> struct property *pp; >> + int rc; >> + >> + if (of_phandle_ht_available()) { > > Likewise, this can't be false either. > OK >> + rc = of_phandle_ht_remove(np); >> + WARN(rc, "remove from phandle hash fail @%s\n", >> + of_node_full_name(np)); >> + } >> >> if (!IS_ENABLED(CONFIG_SYSFS)) >> return; >> diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h >> index 10b0342..386ae71 100644 >> --- a/drivers/of/of_private.h >> +++ b/drivers/of/of_private.h >> @@ -101,4 +101,37 @@ static inline int of_overlay_init(void) >> } >> #endif >> >> +extern const struct rhashtable_params of_phandle_ht_params; >> +extern struct rhashtable *of_phandle_ht; >> + >> +/* for unittest use */ >> +extern bool of_phandle_ht_is_disabled; >> + >> +static inline bool of_phandle_ht_available(void) >> +{ >> + return of_phandle_ht != NULL; >> +} >> + >> +static inline int of_phandle_ht_insert(struct device_node *np) >> +{ >> + if (!np || !np->phandle) >> + return 0; >> + return rhashtable_insert_fast(of_phandle_ht, >> + &np->ht_node, of_phandle_ht_params); >> +} >> + >> +static inline int of_phandle_ht_remove(struct device_node *np) >> +{ >> + if (!np || !np->phandle) >> + return 0; >> + return rhashtable_remove_fast(of_phandle_ht, >> + &np->ht_node, of_phandle_ht_params); >> +} >> + >> +static inline struct device_node *of_phandle_ht_lookup(phandle handle) >> +{ >> + return rhashtable_lookup_fast(of_phandle_ht, >> + &handle, of_phandle_ht_params); >> +} >> + >> #endif /* _LINUX_OF_PRIVATE_H */ >> diff --git a/include/linux/of.h b/include/linux/of.h >> index 18a8e59..9de9a3f 100644 >> --- a/include/linux/of.h >> +++ b/include/linux/of.h >> @@ -25,6 +25,7 @@ >> #include <linux/notifier.h> >> #include <linux/property.h> >> #include <linux/list.h> >> +#include <linux/rhashtable.h> >> >> #include <asm/byteorder.h> >> #include <asm/errno.h> >> @@ -52,6 +53,7 @@ struct device_node { >> phandle phandle; >> const char *full_name; >> struct fwnode_handle fwnode; >> + struct rhash_head ht_node; > > Place next to .phandle as both will be accessed at the same time. > OK. >> >> struct property *properties; >> struct property *deadprops; /* removed properties */ >> -- >> 1.7.12 Regards — Pantelis -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html