From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx107.postini.com [74.125.245.107]) by kanga.kvack.org (Postfix) with SMTP id 2D3E26B0044 for ; Mon, 2 Apr 2012 08:52:13 -0400 (EDT) From: "Luca Porzio (lporzio)" Subject: RE: swap on eMMC and other flash Date: Mon, 2 Apr 2012 12:52:04 +0000 Message-ID: <26E7A31274623843B0E8CF86148BFE326FB55F8B@NTXAVZMBX04.azit.micron.com> References: <201203301744.16762.arnd@arndb.de> <201203301850.22784.arnd@arndb.de> In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins , Arnd Bergmann Cc: Rik van Riel , "linaro-kernel@lists.linaro.org" , "linux-mm@kvack.org" , Alex Lemberg , "linux-kernel@vger.kernel.org" , Saugata Das , Venkatraman S , Yejin Moon , Hyojin Jeong , "linux-mmc@vger.kernel.org" , "kernel-team@android.com" Hugh, Great topics. As per one of Rik original points: > 4) skip writeout of zero-filled pages - this can be a big help > for KVM virtual machines running Windows, since Windows zeroes > out free pages; simply discarding a zero-filled page is not > at all simple in the current VM, where we would have to iterate > over all the ptes to free the swap entry before being able to > free the swap cache page (I am not sure how that locking would > even work) >=20 > with the extra layer of indirection, the locking for this scheme > can be trivial - either the faulting process gets the old page, > or it gets a new one, either way it'll be zero filled >=20 Since it's KVMs realm here, can't KSM simply solve the zero-filled pages pr= oblem avoiding unnecessary burden for the Swap subsystem? Cheers,=20 Luca -- 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