From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 0F1DA6B0002 for ; Tue, 19 Feb 2013 13:57:08 -0500 (EST) Received: by mail-pb0-f43.google.com with SMTP id md12so2399637pbc.30 for ; Tue, 19 Feb 2013 10:57:08 -0800 (PST) Date: Tue, 19 Feb 2013 10:56:27 -0800 (PST) From: Hugh Dickins Subject: Re: Should a swapped out page be deleted from swap cache? In-Reply-To: <512338A6.1030602@gmail.com> Message-ID: References: <512338A6.1030602@gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Ric Mason Cc: Li Haifeng , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Tue, 19 Feb 2013, Ric Mason wrote: > > There is a call of try_to_free_swap in function swap_writepage, if > swap_writepage is call from shrink_page_list path, PageSwapCache(page) == > trure, PageWriteback(page) maybe false, page_swapcount(page) == 0, then will > delete the page from swap cache and free swap slot, where I miss? That's correct. PageWriteback is sure to be false there. page_swapcount usually won't be 0 there, but sometimes it will be, and in that case we do want to delete from swap cache and free the swap slot. Hugh -- 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