Hi Rob,
> On May 10, 2016, at 00:21 , Rob Herring <robherring2@xxxxxxxxx> wrote:
>
> On Mon, May 9, 2016 at 1:11 PM, Pantelis Antoniou
> <pantelis.antoniou@xxxxxxxxxxxx> wrote:
>
> Why this is needed goes here.
>
> Any data on how much time the current code takes?
>
I’ll get some numbers. The current algorithm is exhaustive search of
all nodes (not even nodes that have phandles). So it’s kind of obvious
bad on large blobs.
>> Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
>> ---
>> drivers/of/base.c | 35 ++++++++++++++++++++++++++++++++---
>> drivers/of/dynamic.c | 8 ++++++++
>> drivers/of/of_private.h | 31 +++++++++++++++++++++++++++++++
>> include/linux/of.h | 2 ++
>> 4 files changed, 73 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/of/base.c b/drivers/of/base.c
>> index 20bbc2f..770cb95 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 +42,16 @@ static const char *of_stdout_options;
>>
>> struct kset *of_kset;
>>
>> +const struct rhashtable_params of_phandle_ht_params = {
>> + .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;
>> +bool of_phandle_ht_initialized;
>
> Get rid of this and of_phandle_ht_available. It should always be initialized.
>
Not that simple. We have to support the case where calls are made very early
in the boot sequence before the initialization.
>> +
>> /*
>> * 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 +173,12 @@ int __of_attach_node_post(struct device_node *np)
>> struct property *pp;
>> int rc;
>>
>> + if (of_phandle_ht_available()) {
>> + 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 +211,13 @@ void __init of_core_init(void)
>> struct device_node *np;
>> int ret;
>>
>> + ret = rhashtable_init(&of_phandle_ht, &of_phandle_ht_params);
>> + if (ret) {
>> + pr_warn("devicetree: Failed to initialize hashtable\n");
>> + return;
>> + }
>> + of_phandle_ht_initialized = 1;
>> +
>> /* Create the kset, and register existing nodes */
>> mutex_lock(&of_mutex);
>> of_kset = kset_create_and_add("devicetree", NULL, firmware_kobj);
>> @@ -1073,9 +1097,14 @@ 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 */
>> + if (of_phandle_ht_available() && !in_interrupt())
>> + 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 eb31a55..bdebdf5 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()) {
>> + rc = of_phandle_ht_remove(np);
>> + WARN(rc, "remove from phandle hash fail @%s\n",
>> + of_node_full_name(np));
>
> Can this really fail?
>
No, unless the structure is corrupted. I can move it under DEBUG.
> Rob
> —
Regards
— Pantelis
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