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Commit ca89a517 authored by David Woodhouse's avatar David Woodhouse
Browse files

[JFFS2] Finally eliminate __totlen field from struct jffs2_raw_node_ref 



Well, almost. We'll actually keep a 'TEST_TOTLEN' macro set for now, and keep
doing some paranoia checks to make sure it's all working correctly. But if
TEST_TOTLEN is unset, the size of struct jffs2_raw_node_ref drops from 16
bytes to 12 on 32-bit machines. That's a saving of about half a megabyte of
memory on the OLPC prototype board, with 125K or so nodes in its 512MiB of
flash.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 010b06d6

fs/jffs2/nodelist.c

+108 −7
Original line number Diff line number Diff line
@@ -1052,8 +1052,17 @@ void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
{

	if (!jeb->first_node)

		jeb->first_node = ref;

	if (jeb->last_node)

	if (jeb->last_node) {

		jeb->last_node->next_phys = ref;

#ifdef TEST_TOTLEN

		if (ref_offset(jeb->last_node) + jeb->last_node->__totlen != ref_offset(ref)) {

			printk(KERN_CRIT "Adding new ref %p at (0x%08x-0x%08x) not immediately after previous (0x%08x-0x%08x)\n",

			       ref, ref_offset(ref), ref_offset(ref)+ref->__totlen,

			       ref_offset(jeb->last_node), ref_offset(jeb->last_node)+jeb->last_node->__totlen);

			WARN_ON(1);

		}

#endif

	}

	jeb->last_node = ref;



	switch(ref_flags(ref)) {
@@ -1076,18 +1085,110 @@ void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, 
	c->free_size -= len;

	jeb->free_size -= len;



	/* Set __totlen field... for now */

	ref->__totlen = len;

	ref->next_phys = NULL;

#ifdef TEST_TOTLEN

	/* Set (and test) __totlen field... for now */

	ref->__totlen = len;

	ref_totlen(c, jeb, ref);

#endif

}



/* No locking. Do not use on a live file system */

int jffs2_scan_dirty_space(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

			   uint32_t size)

{

	if (!size)

		return 0;

	if (size > c->sector_size - jeb->used_size) {

		printk(KERN_CRIT "Dirty space 0x%x larger then used_size 0x%x (wasted 0x%x)\n",

		       size, jeb->used_size, jeb->wasted_size);

		BUG();

	}

	if (jeb->last_node && ref_obsolete(jeb->last_node)) {

#ifdef TEST_TOTLEN

		jeb->last_node->__totlen += size;

#endif

		c->dirty_size += size;

		c->free_size -= size;

		jeb->dirty_size += size;

		jeb->free_size -= size;

	} else {

		struct jffs2_raw_node_ref *ref;

		ref = jffs2_alloc_raw_node_ref();

		if (!ref)

			return -ENOMEM;



		ref->flash_offset = jeb->offset + c->sector_size - jeb->free_size;

		ref->flash_offset |= REF_OBSOLETE;

		ref->next_in_ino = 0;

#ifdef TEST_TOTLEN

		ref->__totlen = size;

#endif



		jffs2_link_node_ref(c, jeb, ref, size);

	}



	return 0;

}



/* Calculate totlen from surrounding nodes or eraseblock */

static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,

				    struct jffs2_eraseblock *jeb,

				    struct jffs2_raw_node_ref *ref)

{

	uint32_t ref_end;



	if (ref->next_phys)

		ref_end = ref_offset(ref->next_phys);

	else {

		if (!jeb)

			jeb = &c->blocks[ref->flash_offset / c->sector_size];



		/* Last node in block. Use free_space */

		if (ref != jeb->last_node) {

			printk(KERN_CRIT "ref %p @0x%08x is not jeb->last_node (%p @0x%08x)\n",

			       ref, ref_offset(ref), jeb->last_node, jeb->last_node?ref_offset(jeb->last_node):0);

			BUG();

		}

		ref_end = jeb->offset + c->sector_size - jeb->free_size;

	}

	return ref_end - ref_offset(ref);

}



uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

			    struct jffs2_raw_node_ref *ref)

{

	uint32_t ret;



#if CONFIG_JFFS2_FS_DEBUG > 0

	if (jeb && jeb != &c->blocks[ref->flash_offset / c->sector_size]) {

		printk(KERN_CRIT "ref_totlen called with wrong block -- at 0x%08x instead of 0x%08x; ref 0x%08x\n",

		       jeb->offset, c->blocks[ref->flash_offset / c->sector_size].offset, ref_offset(ref));

		BUG();

	}

#endif



	ret = __ref_totlen(c, jeb, ref);

#ifdef TEST_TOTLEN

	if (ret != ref->__totlen) {

		printk(KERN_CRIT "Totlen for ref at %p (0x%08x-0x%08x) miscalculated as 0x%x instead of %x\n",

		       ref, ref_offset(ref), ref_offset(ref)+ref->__totlen,

		       ret, ref->__totlen);

		if (ref->next_phys) {

			printk(KERN_CRIT "next_phys %p (0x%08x-0x%08x)\n", ref->next_phys, ref_offset(ref->next_phys),

			       ref_offset(ref->next_phys)+ref->__totlen);

		} else 

			printk(KERN_CRIT "No next_phys. jeb->last_node is %p\n", jeb->last_node);



		printk(KERN_CRIT "jeb->wasted_size %x, dirty_size %x, used_size %x, free_size %x\n", jeb->wasted_size, jeb->dirty_size, jeb->used_size, jeb->free_size);

		ret = ref->__totlen;

		if (!jeb)

			jeb = &c->blocks[ref->flash_offset / c->sector_size];

#if defined(JFFS2_DBG_DUMPS) || defined(JFFS2_DBG_PARANOIA_CHECKS)

		__jffs2_dbg_dump_node_refs_nolock(c, jeb);

#endif

		WARN_ON(1);

	}

#endif /* TEST_TOTLEN */

	return ret;

}

fs/jffs2/nodelist.h

+7 −51
Original line number Diff line number Diff line
@@ -82,7 +82,10 @@ struct jffs2_raw_node_ref 
		word so you know when you've got there :) */

	struct jffs2_raw_node_ref *next_phys;

	uint32_t flash_offset;

#define TEST_TOTLEN

#ifdef TEST_TOTLEN

	uint32_t __totlen; /* This may die; use ref_totlen(c, jeb, ) below */

#endif

};



        /* flash_offset & 3 always has to be zero, because nodes are
@@ -221,57 +224,7 @@ static inline int jffs2_blocks_use_vmalloc(struct jffs2_sb_info *c) 
	return ((c->flash_size / c->sector_size) * sizeof (struct jffs2_eraseblock)) > (128 * 1024);

}



/* Calculate totlen from surrounding nodes or eraseblock */

static inline uint32_t __ref_totlen(struct jffs2_sb_info *c,

				    struct jffs2_eraseblock *jeb,

				    struct jffs2_raw_node_ref *ref)

{

	uint32_t ref_end;



	if (ref->next_phys)

		ref_end = ref_offset(ref->next_phys);

	else {

		if (!jeb)

			jeb = &c->blocks[ref->flash_offset / c->sector_size];



		/* Last node in block. Use free_space */

		BUG_ON(ref != jeb->last_node);

		ref_end = jeb->offset + c->sector_size - jeb->free_size;

	}

	return ref_end - ref_offset(ref);

}



static inline uint32_t ref_totlen(struct jffs2_sb_info *c,

				  struct jffs2_eraseblock *jeb,

				  struct jffs2_raw_node_ref *ref)

{

	uint32_t ret;



#if CONFIG_JFFS2_FS_DEBUG > 0

	if (jeb && jeb != &c->blocks[ref->flash_offset / c->sector_size]) {

		printk(KERN_CRIT "ref_totlen called with wrong block -- at 0x%08x instead of 0x%08x; ref 0x%08x\n",

		       jeb->offset, c->blocks[ref->flash_offset / c->sector_size].offset, ref_offset(ref));

		BUG();

	}

#endif



#if 1

	ret = ref->__totlen;

#else

	/* This doesn't actually work yet */

	ret = __ref_totlen(c, jeb, ref);

	if (ret != ref->__totlen) {

		printk(KERN_CRIT "Totlen for ref at %p (0x%08x-0x%08x) miscalculated as 0x%x instead of %x\n",

		       ref, ref_offset(ref), ref_offset(ref)+ref->__totlen,

		       ret, ref->__totlen);

		if (!jeb)

			jeb = &c->blocks[ref->flash_offset / c->sector_size];

		jffs2_dbg_dump_node_refs_nolock(c, jeb);

		BUG();

	}

#endif

	return ret;

}

#define ref_totlen(a, b, c) __jffs2_ref_totlen((a), (b), (c))



#define ALLOC_NORMAL	0	/* Normal allocation */

#define ALLOC_DELETION	1	/* Deletion node. Best to allow it */
@@ -355,6 +308,9 @@ void jffs2_truncate_fragtree (struct jffs2_sb_info *c, struct rb_root *list, uin 
int jffs2_add_older_frag_to_fragtree(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_tmp_dnode_info *tn);

void jffs2_link_node_ref(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,

			 struct jffs2_raw_node_ref *ref, uint32_t len);

extern uint32_t __jffs2_ref_totlen(struct jffs2_sb_info *c,

				   struct jffs2_eraseblock *jeb,

				   struct jffs2_raw_node_ref *ref);



/* nodemgmt.c */

int jffs2_thread_should_wake(struct jffs2_sb_info *c);

fs/jffs2/nodemgmt.c

+6 −0
Original line number Diff line number Diff line
@@ -386,7 +386,9 @@ int jffs2_add_physical_node_ref(struct jffs2_sb_info *c, struct jffs2_raw_node_r 
	struct jffs2_eraseblock *jeb;



	jeb = &c->blocks[new->flash_offset / c->sector_size];

#ifdef TEST_TOTLEN

	new->__totlen = len;

#endif



	D1(printk(KERN_DEBUG "jffs2_add_physical_node_ref(): Node at 0x%x(%d), size 0x%x\n", ref_offset(new), ref_flags(new), len));

#if 1
@@ -679,7 +681,9 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref 


		spin_lock(&c->erase_completion_lock);



#ifdef TEST_TOTLEN

		ref->__totlen += n->__totlen;

#endif

		ref->next_phys = n->next_phys;

                if (jeb->last_node == n) jeb->last_node = ref;

		if (jeb->gc_node == n) {
@@ -702,7 +706,9 @@ void jffs2_mark_node_obsolete(struct jffs2_sb_info *c, struct jffs2_raw_node_ref 
			p = p->next_phys;



		if (ref_obsolete(p) && !ref->next_in_ino) {

#ifdef TEST_TOTLEN

			p->__totlen += ref->__totlen;

#endif

			if (jeb->last_node == ref) {

				jeb->last_node = p;

			}