On 02/16/18 14:20, Frank Rowand wrote: > On 02/16/18 01:04, Chintan Pandya wrote: >> >> >> On 2/15/2018 6:22 AM, [email protected] wrote: >>> From: Frank Rowand <[email protected]> >>> >>> Create a cache of the nodes that contain a phandle property. Use this >>> cache to find the node for a given phandle value instead of scanning >>> the devicetree to find the node. If the phandle value is not found >>> in the cache, of_find_node_by_phandle() will fall back to the tree >>> scan algorithm. >>> > > < snip > > >>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>> index ad28de96e13f..ab545dfa9173 100644 >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -91,10 +91,69 @@ int __weak of_node_to_nid(struct device_node *np) >>> } >>> #endif >>> +static struct device_node **phandle_cache; >>> +static u32 phandle_cache_mask; >>> + >>> +/* >>> + * Assumptions behind phandle_cache implementation: >>> + * - phandle property values are in a contiguous range of 1..n >>> + * >>> + * If the assumptions do not hold, then >>> + * - the phandle lookup overhead reduction provided by the cache >>> + * will likely be less >>> + */ >>> +static void of_populate_phandle_cache(void) >>> +{ >>> + unsigned long flags; >>> + u32 cache_entries; >>> + struct device_node *np; >>> + u32 phandles = 0; >>> + >>> + raw_spin_lock_irqsave(&devtree_lock, flags); >>> + >>> + kfree(phandle_cache); >> >> I couldn't understood this. Everything else looks good to me. > > I will be adding a call to of_populate_phandle_cache() from the > devicetree overlay code. I put the kfree here so that the previous > cache memory is freed when a new cache is created. > > Adding the call from the overlay code is not done in this > series because I have a patch series modifying overlays and > I do not want to create a conflict or ordering between that > series and that patch. The lack of the call from overlay ^^^^ this
> code means that overlay code will gain some of the overhead > reduction from this patch, but possibly not the entire reduction. > > >> >>> + phandle_cache = NULL; >>> + >>> + for_each_of_allnodes(np) > > < snip > >
