From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx200.postini.com [74.125.245.200]) by kanga.kvack.org (Postfix) with SMTP id 0B2516B004A for ; Sat, 31 Mar 2012 05:24:34 -0400 (EDT) From: Arnd Bergmann Subject: Re: swap on eMMC and other flash Date: Sat, 31 Mar 2012 09:24:19 +0000 References: <201203301744.16762.arnd@arndb.de> <201203301850.22784.arnd@arndb.de> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201203310924.19708.arnd@arndb.de> Sender: owner-linux-mm@kvack.org List-ID: To: Zach Pfeffer Cc: linaro-kernel@lists.linaro.org, linux-mm@kvack.org, Alex Lemberg , "linux-mmc@vger.kernel.org" , linux-kernel@vger.kernel.org, Hyojin Jeong , "Luca Porzio (lporzio)" , kernel-team@android.com, Yejin Moon On Friday 30 March 2012, Zach Pfeffer wrote: > Last I read Transparent Huge Pages are still paged in and out a page > at a time, is this or was this ever the case? If it is the case should > the paging system be extended to support THP which would take care of > the big block issues with flash media? > I don't think we ever want to get /that/ big. As I mentioned, going beyond 64kb does not improve throughput on most flash media. However, paging out 16MB causes a very noticeable delay of up to a few seconds on slow drives, which would be inacceptable to users. Also, that would only deal with the rare case where the data you want to page out is actually in huge pages, not the common case. Arnd -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org