From mboxrd@z Thu Jan 1 00:00:00 1970 In-reply-to: <48FC9CCC.3040006@linux-foundation.org> (message from Christoph Lameter on Mon, 20 Oct 2008 09:59:24 -0500) Subject: Re: SLUB defrag pull request? References: <1223883004.31587.15.camel@penberg-laptop> <1223883164.31587.16.camel@penberg-laptop> <200810132354.30789.nickpiggin@yahoo.com.au> <48F378C6.7030206@linux-foundation.org> <48FC9CCC.3040006@linux-foundation.org> Message-Id: From: Miklos Szeredi Date: Mon, 20 Oct 2008 20:01:58 +0200 Sender: owner-linux-mm@kvack.org Return-Path: To: cl@linux-foundation.org Cc: miklos@szeredi.hu, penberg@cs.helsinki.fi, nickpiggin@yahoo.com.au, hugh@veritas.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org List-ID: On Mon, 20 Oct 2008, Christoph Lameter wrote: > >> kick_inodes() only works on inodes that first have undergone > >> get_inodes() where we establish a refcount under inode_lock(). The final > >> cleanup in kick_inodes() is done under iprune_mutex. You are looking at > >> the loop that does writeback and invalidates attached dentries. This can > >> fail for various reasons. > > > > Yes, but I'm not at all sure that calling remove_inode_buffers() or > > invalidate_mapping_pages() is OK on a live inode. They should be done > > after checking the refcount, just like prune_icache() does. > > Dont we do the same on a truncate? Yes, with i_mutex and i_alloc_sem held. > > > Also, while d_invalidate() is not actually wrong here, because you > > check S_ISDIR(), but it's still the wrong function to use. You really > > just want to shrink the children. Invalidation means: the filesystem > > found out that the cached inode is invalid, so we want to throw it > > away. In the future it might actually be able to do it for > > directories as well, but currently it cannot because of possible > > mounts on the dentry. > > Thats the same issue as with the dentries. The new function could deal with > both situations? Sure. The big issue is dealing with umount. You could do something like grab_super() on sb before getting a ref on the inode/dentry. But I'm not sure this is a good idea. There must be a simpler way to achieve this... Miklos -- 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