From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 7 Nov 2007 11:31:24 +0100 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [patch 14/23] inodes: Support generic defragmentation Message-ID: <20071107103124.GD7374@lazybastard.org> References: <20071107011130.382244340@sgi.com> <20071107011229.893091119@sgi.com> <20071107101748.GC7374@lazybastard.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20071107101748.GC7374@lazybastard.org> Sender: owner-linux-mm@kvack.org Return-Path: To: =?utf-8?B?SsO2cm4=?= Engel Cc: Christoph Lameter , akpm@linux-foundatin.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman List-ID: On Wed, 7 November 2007 11:17:48 +0100, JA?rn Engel wrote: > > +/* > > + * Function for filesystems that embedd struct inode into their own > > + * structures. The offset is the offset of the struct inode in the fs inode. > > + */ > > +void *fs_get_inodes(struct kmem_cache *s, int nr, void **v, > > + unsigned long offset) > > +{ > > + int i; > > + > > + for (i = 0; i < nr; i++) > > + v[i] += offset; > > + > > + return get_inodes(s, nr, v); > > +} > > +EXPORT_SYMBOL(fs_get_inodes); > > The fact that all pointers get changed makes me a bit uneasy: > struct foo_inode v[20]; > ... > fs_get_inodes(..., v, ...); > ... > v[0].foo_field = bar; > > No warning, but spectacular fireworks. > > > +void kick_inodes(struct kmem_cache *s, int nr, void **v, void *private) > > +{ > > + struct inode *inode; > > + int i; > > + int abort = 0; > > + LIST_HEAD(freeable); > > + struct super_block *sb; > > + > > + for (i = 0; i < nr; i++) { > > + inode = v[i]; > > + if (!inode) > > + continue; > > NULL is legal here? Then fs_get_inodes should check for NULL as well > and not add the offset to NULL pointers, I guess. Ignore these two comments. Reading further before making them would have helped. ;) JA?rn -- Fancy algorithms are slow when n is small, and n is usually small. Fancy algorithms have big constants. Until you know that n is frequently going to be big, don't get fancy. -- Rob Pike -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org