From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb0-f197.google.com (mail-yb0-f197.google.com [209.85.213.197]) by kanga.kvack.org (Postfix) with ESMTP id AF4646B0038 for ; Mon, 17 Oct 2016 10:12:48 -0400 (EDT) Received: by mail-yb0-f197.google.com with SMTP id g68so32559482ybi.1 for ; Mon, 17 Oct 2016 07:12:48 -0700 (PDT) Received: from mail-qk0-f196.google.com (mail-qk0-f196.google.com. [209.85.220.196]) by mx.google.com with ESMTPS id u63si8417260ybf.321.2016.10.17.07.12.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 17 Oct 2016 07:12:47 -0700 (PDT) Received: by mail-qk0-f196.google.com with SMTP id n189so14207980qke.1 for ; Mon, 17 Oct 2016 07:12:47 -0700 (PDT) Date: Mon, 17 Oct 2016 16:12:46 +0200 From: Michal Hocko Subject: Re: [PATCH] shmem: avoid huge pages for small files Message-ID: <20161017141245.GC27459@dhcp22.suse.cz> References: <20161017121809.189039-1-kirill.shutemov@linux.intel.com> <20161017123021.rlyz44dsf4l4xnve@black.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161017123021.rlyz44dsf4l4xnve@black.fi.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Hugh Dickins , Andrea Arcangeli , Andrew Morton , Andi Kleen , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon 17-10-16 15:30:21, Kirill A. Shutemov wrote: [...] > >From fd0b01b9797ddf2bef308c506c42d3dd50f11793 Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" > Date: Mon, 17 Oct 2016 14:44:47 +0300 > Subject: [PATCH] shmem: avoid huge pages for small files > > Huge pages are detrimental for small file: they causes noticible > overhead on both allocation performance and memory footprint. > > This patch aimed to address this issue by avoiding huge pages until file > grown to specified size. This would cover most of the cases where huge > pages causes regressions in performance. > > By default the minimal file size to allocate huge pages is equal to size > of huge page. ok > We add two handle to specify minimal file size for huge pages: > > - mount option 'huge_min_size'; > > - sysfs file /sys/kernel/mm/transparent_hugepage/shmem_min_size for > in-kernel tmpfs mountpoint; Could you explain who might like to change the minimum value (other than disable the feautre for the mount point) and for what reason? [...] > @@ -238,6 +238,12 @@ values: > - "force": > Force the huge option on for all - very useful for testing; > > +Tehre's limit on minimal file size before kenrel starts allocate huge > +pages for it. By default it's size of huge page. Smoe tyopse -- Michal Hocko SUSE Labs -- 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