From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Liu Subject: Re: tmem frontswap without swap file Date: Tue, 25 Feb 2014 12:52:16 +0800 Message-ID: <530C2180.5060508@oracle.com> References: <530ABD5C.10506@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Vasiliy Tolstov Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 02/24/2014 07:01 PM, Vasiliy Tolstov wrote: > 2014-02-24 7:32 GMT+04:00 Bob Liu : >> Two types of page can be stored in tmem: persistent_page and ephemeral_page. >> >> Persistent pages are swapped-out pages, whose date can't be dropped by >> tmem. The rule for persistent pages is: >> 'current_domain_pages + persistent_pages have to smaller than >> domain->max_pages'. >> >> Ephemeral pages are clean pagecache pages, those pages have a copy in >> disk already. >> The amount number of ephemeral pages are not limited, but XEN host will >> reclaim those pages if under memory pressure. >> There is a tmem parameter 'weight' which can be used to control how many >> ephemeral_pages should be reclaimed between domains. > > > Very good, thanks for answers! What minimal kernel versions recommends > for frontswap/cleancache in domU (dom0 xen 4.3.2) > Any version started from v3.5 should be okay, I'd recommend versions after v3.10 since there were hardly no commits since that version. And I suggest you apply this patch also(which haven't been merged to linus' git tree yet) https://git.kernel.org/cgit/linux/kernel/git/konrad/xen.git/commit/?h=stable/for-linus-3.14&id=bc1b0df59e3fc4573f92bc1aab9652047a0aeaa7 -- Regards, -Bob