From 749cbaca7f5406e23bbf0009477c73e14fa8a9ff Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky <pfalcon@users.sourceforge.net>
Date: Fri, 1 Jul 2016 00:09:55 +0300
Subject: [PATCH] py/gc: Calculate (and report) maximum contiguous free block
 size.

Just as maximum allocated block size, it's reported in allocation units
(not bytes).
---
 py/gc.c | 14 +++++++++++---
 py/gc.h |  1 +
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/py/gc.c b/py/gc.c
index 2cc64f3620..1c1865cdb4 100644
--- a/py/gc.c
+++ b/py/gc.c
@@ -324,15 +324,17 @@ void gc_info(gc_info_t *info) {
     info->total = MP_STATE_MEM(gc_pool_end) - MP_STATE_MEM(gc_pool_start);
     info->used = 0;
     info->free = 0;
+    info->max_free = 0;
     info->num_1block = 0;
     info->num_2block = 0;
     info->max_block = 0;
     bool finish = false;
-    for (size_t block = 0, len = 0; !finish;) {
+    for (size_t block = 0, len = 0, len_free = 0; !finish;) {
         size_t kind = ATB_GET_KIND(block);
         switch (kind) {
             case AT_FREE:
                 info->free += 1;
+                len_free += 1;
                 len = 0;
                 break;
 
@@ -367,6 +369,12 @@ void gc_info(gc_info_t *info) {
             if (len > info->max_block) {
                 info->max_block = len;
             }
+            if (finish || kind == AT_HEAD) {
+                if (len_free > info->max_free) {
+                    info->max_free = len_free;
+                }
+                len_free = 0;
+            }
         }
     }
 
@@ -726,8 +734,8 @@ void gc_dump_info(void) {
     gc_info(&info);
     mp_printf(&mp_plat_print, "GC: total: %u, used: %u, free: %u\n",
         (uint)info.total, (uint)info.used, (uint)info.free);
-    mp_printf(&mp_plat_print, " No. of 1-blocks: %u, 2-blocks: %u, max blk sz: %u\n",
-           (uint)info.num_1block, (uint)info.num_2block, (uint)info.max_block);
+    mp_printf(&mp_plat_print, " No. of 1-blocks: %u, 2-blocks: %u, max blk sz: %u, max free sz: %u\n",
+           (uint)info.num_1block, (uint)info.num_2block, (uint)info.max_block, (uint)info.max_free);
 }
 
 void gc_dump_alloc_table(void) {
diff --git a/py/gc.h b/py/gc.h
index e790c34ac0..7d8fe2bf8c 100644
--- a/py/gc.h
+++ b/py/gc.h
@@ -54,6 +54,7 @@ typedef struct _gc_info_t {
     size_t total;
     size_t used;
     size_t free;
+    size_t max_free;
     size_t num_1block;
     size_t num_2block;
     size_t max_block;