From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755313AbbIYIEm (ORCPT ); Fri, 25 Sep 2015 04:04:42 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:35463 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753483AbbIYIEj (ORCPT ); Fri, 25 Sep 2015 04:04:39 -0400 Date: Fri, 25 Sep 2015 17:05:25 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Seth Jennings , Vitaly Wool , Dan Streetman , Andrew Morton , Sergey Senozhatsky , linux-kernel , Linux-MM Subject: Re: [PATCH v2] zbud: allow up to PAGE_SIZE allocations Message-ID: <20150925080525.GE865@swordfish> References: <20150922141733.d7d97f59f207d0655c3b881d@gmail.com> <20150923031845.GA31207@cerebellum.local.variantweb.net> <20150923215726.GA17171@cerebellum.local.variantweb.net> <20150925021325.GA16431@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150925021325.GA16431@bbox> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (09/25/15 11:13), Minchan Kim wrote: > > Ok, I can see that having the allocator backends for zpool > > have the same set of constraints is nice. > > Sorry for delay. I'm on vacation until next week. > It seems Seth was missed in previous discusstion which was not the end. > > I already said questions, opinion and concerns but anything is not clear > until now. Only clear thing I could hear is just "compaction stats are > better" which is not enough for me. Sorry. Agree. There weren't lots of answers, really. Vitaly, Have you seen those symptoms before? How did you come up to a conclusion that zram->zbud will do the trick? If those symptoms are some sort of a recent addition, then does it help when you disable zsmalloc compaction? --- diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index f59e8eb..b6c6a19 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1944,8 +1944,8 @@ struct zs_pool *zs_create_pool(const char *name, gfp_t flags) * Not critical, we still can use the pool * and user can trigger compaction manually. */ - if (zs_register_shrinker(pool) == 0) - pool->shrinker_enabled = true; +/* if (zs_register_shrinker(pool) == 0) + pool->shrinker_enabled = true;*/ return pool; err: --- p.s. I'll be on vacation next week, so most likely will be quite slow to answer. -ss > > 1) https://lkml.org/lkml/2015/9/15/33 > 2) https://lkml.org/lkml/2015/9/21/2 > > Vitally, Please say what's the root cause of your problem and if it > is external fragmentation, what's the problem of my approach? > > 1) make non-LRU page migrate > 2) provide zsmalloc's migratpage > > We should provide it for CMA as well as external fragmentation. > I think we could solve your issue with above approach and > it fundamentally makes zsmalloc/zbud happy in future. > > Also, please keep it in mind that zram has been in linux kernel for > memory efficiency for a long time and later zswap/zbud was born > for *determinism* at the cost of memory efficiency. > > Thanks. > > -- > 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 >