[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20090609030726.GA8026@localhost>
Date: Tue, 9 Jun 2009 11:07:26 +0800
From: Wu Fengguang <fengguang.wu@...el.com>
To: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc: LKML <linux-kernel@...r.kernel.org>,
"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
"linux-btrfs@...r.kernel.org" <linux-btrfs@...r.kernel.org>,
"chris.mason@...cle.com" <chris.mason@...cle.com>
Subject: Re: sk_lock: inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W}
usage
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).
Thanks,
Fengguang
> Can't nfs does similar hack?
>
>
> I'm not net nor nfs expert. perhaps I'm wrong :-)
>
>
> Thanks.
>
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists