From 46f347899188a1491d8f3f43cb47495766aa839a Mon Sep 17 00:00:00 2001
From: Charles Manning <cdhmanning@gmail.com>
Date: Fri, 3 Sep 2010 14:05:49 +1200
Subject: [PATCH] yaffs Add stats tracking and control for background gc
 instrumentation

This allows us to track the impact of background gc.

Signed-off-by: Charles Manning <cdhmanning@gmail.com>
---
 yaffs_fs.c   | 7 +++++--
 yaffs_guts.c | 2 ++
 yaffs_guts.h | 1 +
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/yaffs_fs.c b/yaffs_fs.c
index c3f11f4..dfb5461 100644
--- a/yaffs_fs.c
+++ b/yaffs_fs.c
@@ -158,6 +158,7 @@ unsigned int yaffs_traceMask = YAFFS_TRACE_BAD_BLOCKS | YAFFS_TRACE_ALWAYS;
 unsigned int yaffs_wr_attempts = YAFFS_WR_ATTEMPTS;
 unsigned int yaffs_auto_checkpoint = 1;
 unsigned int yaffs_gc_control = 1;
+unsigned int yaffs_bg_enable = 1;
 
 /* Module Parameters */
 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
@@ -165,6 +166,7 @@ module_param(yaffs_traceMask, uint, 0644);
 module_param(yaffs_wr_attempts, uint, 0644);
 module_param(yaffs_auto_checkpoint, uint, 0644);
 module_param(yaffs_gc_control, uint, 0644);
+module_param(yaffs_bg_enable, uint, 0644);
 #else
 MODULE_PARM(yaffs_traceMask, "i");
 MODULE_PARM(yaffs_wr_attempts, "i");
@@ -2314,12 +2316,12 @@ static int yaffs_BackgroundThread(void *data)
 
 		now = jiffies;
 
-		if(time_after(now, next_dir_update)){
+		if(time_after(now, next_dir_update) && yaffs_bg_enable){
 			yaffs_UpdateDirtyDirectories(dev);
 			next_dir_update = now + HZ;
 		}
 
-		if(time_after(now,next_gc)){
+		if(time_after(now,next_gc) && yaffs_bg_enable){
 			if(!dev->isCheckpointed){
 				urgency = yaffs_bg_gc_urgency(dev);
 				gcResult = yaffs_BackgroundGarbageCollect(dev, urgency);
@@ -3188,6 +3190,7 @@ static char *yaffs_dump_dev_part1(char *buf, yaffs_Device * dev)
 	buf += sprintf(buf, "allGCs............. %u\n", dev->allGCs);
 	buf += sprintf(buf, "passiveGCs......... %u\n", dev->passiveGCs);
 	buf += sprintf(buf, "oldestDirtyGCs..... %u\n", dev->oldestDirtyGCs);
+	buf += sprintf(buf, "nGCBlocks.......... %u\n", dev->nGCBlocks);
 	buf += sprintf(buf, "backgroundGCs...... %u\n", dev->backgroundGCs);
 	buf += sprintf(buf, "nRetriedWrites..... %u\n", dev->nRetriedWrites);
 	buf += sprintf(buf, "nRetireBlocks...... %u\n", dev->nRetiredBlocks);
diff --git a/yaffs_guts.c b/yaffs_guts.c
index a1782e7..389a57c 100644
--- a/yaffs_guts.c
+++ b/yaffs_guts.c
@@ -2500,8 +2500,10 @@ static unsigned yaffs_FindBlockForGarbageCollection(yaffs_Device *dev,
 		  dev->param.nChunksPerBlock - dev->gcPagesInUse,
 		  prioritised));
 
+		dev->nGCBlocks++;
 		if(background)
 			dev->backgroundGCs++;
+
 		dev->gcDirtiest = 0;
 		dev->gcPagesInUse = 0;
 		dev->gcNotDone = 0;
diff --git a/yaffs_guts.h b/yaffs_guts.h
index 6d4ae46..f9b5ac1 100644
--- a/yaffs_guts.h
+++ b/yaffs_guts.h
@@ -759,6 +759,7 @@ struct yaffs_DeviceStruct {
 	__u32 allGCs;
 	__u32 passiveGCs;
 	__u32 oldestDirtyGCs;
+	__u32 nGCBlocks;
 	__u32 backgroundGCs;
 	__u32 nRetriedWrites;
 	__u32 nRetiredBlocks;
-- 
2.30.2