From mboxrd@z Thu Jan 1 00:00:00 1970 From: KOSAKI Motohiro Subject: Re: sk_lock: inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage Date: Tue, 9 Jun 2009 12:15:03 +0900 (JST) Message-ID: <20090609121436.DD56.A69D9226@jp.fujitsu.com> References: <20090608134428.4373.A69D9226@jp.fujitsu.com> <20090609030726.GA8026@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Cc: kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org, LKML , "linux-nfs@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-btrfs@vger.kernel.org" , "chris.mason@oracle.com" To: Wu Fengguang Return-path: Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:44488 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752734AbZFIDPD (ORCPT ); Mon, 8 Jun 2009 23:15:03 -0400 In-Reply-To: <20090609030726.GA8026@localhost> Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Mon, Jun 08, 2009 at 12:55:18PM +0800, KOSAKI Motohiro wrote: > > Hi > > > > > Hi, > > > > > > This lockdep warning appears when doing stress memory tests over NFS. > > > > > > page reclaim => nfs_writepage => tcp_sendmsg => lock sk_lock > > > > > > tcp_close => lock sk_lock => tcp_send_fin => alloc_skb_fclone => page reclaim > > > > > > Any ideas? > > > > AFAIK, btrfs has re-dirty hack. > > > > ------------------------------------------------------------------ > > static int btrfs_writepage(struct page *page, struct writeback_control *wbc) > > { > > struct extent_io_tree *tree; > > > > > > if (current->flags & PF_MEMALLOC) { > > redirty_page_for_writepage(wbc, page); > > unlock_page(page); > > return 0; > > } > > tree = &BTRFS_I(page->mapping->host)->io_tree; > > return extent_write_full_page(tree, page, btrfs_get_extent, wbc); > > } > > --------------------------------------------------------------- > > > > PF_MEMALLOC mean caller is try_to_free_pages(). (not normal write nor kswapd) > > No, kswapd also sets the PF_MEMALLOC flag. It looks like btrfs_writepage() > is trying to avoid inefficient page outs at the cost of pinning dirty > pages in memory (even when we really want free pages). Sorry, I was confused ;)