[ECOS] JFFS2 eats memory

["Øyvind Harboe" <oyvind.harboe@zylin.com>]

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This issue has been discussed before, and although I have a workaround,
I'd dearly like to have it put to bed since it is starting to cause
problems elsewhere in my application:

- My code opens a file for writing with O_TRUNC set, performs
a single write call, closes the file.
- After closing the file, JFFS2 has eaten memory.
- With the attached modifcations to JFFS2, it "only" eats 24 bytes.
- If I unmount and remount JFFS2, no memory is "lost" and JFFS2 works
fine.

Presumably when the raw nodes in the file fragement list are marked as
obsolete, they are no longer required, but are not freed.

Q: Is this fundamentally impossible or a "bad idea" to fix?


-- 
Øyvind Harboe
http://www.zylin.com


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Index: src/fs-ecos.c
===================================================================
RCS file: /cvs/ecos/ecos/packages/fs/jffs2/current/src/fs-ecos.c,v
retrieving revision 1.27
diff -u -w -r1.27 fs-ecos.c
--- src/fs-ecos.c	21 Apr 2004 18:51:21 -0000	1.27
+++ src/fs-ecos.c	12 Jul 2004 14:25:41 -0000
@@ -199,7 +199,9 @@
 	// held where needed for dotdot filepaths)
 	while (this) {
 		next = this->i_cache_next;
-		if (this != i && this->i_count == 0) {
+		if (
+		    //this != i && 
+		    this->i_count == 0) {
 			struct _inode *parent = this->i_parent;
 			if (this->i_cache_next)
 				this->i_cache_next->i_cache_prev = this->i_cache_prev;
@@ -1466,12 +1468,22 @@
 {
 	struct _inode *node = (struct _inode *) fp->f_data;
 
+	// cache values before we destroy the node
+	struct jffs2_sb_info *c = JFFS2_SB_INFO(node->i_sb);
+	struct _inode *root = node->i_sb->s_root;
+
 	D2(printf("jffs2_fo_close\n"));
 
 	jffs2_iput(node);
 
 	fp->f_data = 0;		// zero data pointer
 
+
+	// free as much of cached structures as possible to make sure
+	// that memory usage stays stable and that idle memory usage
+	// is at a minimum.
+	icache_evict(root, node);	
+
 	return ENOERR;
 }
 


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