Function stack size usage (was [PATCH][1/2] SquashFS)

[Phillip Lougher]

Andrew Morton wrote:
> Phillip Lougher <phillip@xxxxxxxxxxxxxxxxxxx> wrote:
> > +static struct inode *squashfs_iget(struct super_block *s, squashfs_inode inode)
> > +{
> > +	struct inode *i;
> > +	squashfs_sb_info *msBlk = (squashfs_sb_info *)s->s_fs_info;
> > +	squashfs_super_block *sBlk = &msBlk->sBlk;
> > +	unsigned int block = SQUASHFS_INODE_BLK(inode) +
> > +		sBlk->inode_table_start;
> > +	unsigned int offset = SQUASHFS_INODE_OFFSET(inode);
> > +	unsigned int ino = SQUASHFS_MK_VFS_INODE(block
> > +		- sBlk->inode_table_start, offset);
> > +	unsigned int next_block, next_offset;
> > +	squashfs_base_inode_header inodeb;
>
>
> How much stack space is being used here?  Perhaps you should run
> scripts/checkstack.pl across the whole thing.

A lot of the functions use a fair amount of stack (I never thought it 
was excessive)...  This is the result of running checkstack.pl against 
the code on Intel.

0x00003a3c get_dir_index_using_name:                    596
0x00000d80 squashfs_iget:                               488
0x000044d8 squashfs_lookup:                             380
0x00003d00 squashfs_readdir:                            372
0x000020fe squashfs_fill_super:                         316
0x000031b8 squashfs_readpage:                           308
0x00002f5c read_blocklist:                              296
0x00003634 squashfs_readpage4K:                         284

A couple of these functions show a fair amount of stack use.  What is 
the maximum acceptable usage, i.e. do any of the above functions need 
work to reduce their stack usage?

Thanks

Phillip
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