percpu: update embedding first chunk allocator to handle sparse units

Now that percpu core can handle very sparse units, given that vmalloc
space is large enough, embedding first chunk allocator can use any
memory to build the first chunk.  This patch teaches
pcpu_embed_first_chunk() about distances between cpus and to use
alloc/free callbacks to allocate node specific areas for each group
and use them for the first chunk.

This brings the benefits of embedding allocator to NUMA configurations
- no extra TLB pressure with the flexibility of unified dynamic
allocator and no need to restructure arch code to build memory layout
suitable for percpu.  With units put into atom_size aligned groups
according to cpu distances, using large page for dynamic chunks is
also easily possible with falling back to reuglar pages if large
allocation fails.

Embedding allocator users are converted to specify NULL
cpu_distance_fn, so this patch doesn't cause any visible behavior
difference.  Following patches will convert them.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index a7ec840f596c..25359932740e 100644
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -110,8 +110,11 @@ extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 					 void *base_addr);
 
 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
-extern int __init pcpu_embed_first_chunk(size_t reserved_size,
-					 ssize_t dyn_size);
+extern int __init pcpu_embed_first_chunk(size_t reserved_size, ssize_t dyn_size,
+				size_t atom_size,
+				pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
+				pcpu_fc_alloc_fn_t alloc_fn,
+				pcpu_fc_free_fn_t free_fn);
 #endif
 
 #ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK