From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f198.google.com (mail-ua0-f198.google.com [209.85.217.198]) by kanga.kvack.org (Postfix) with ESMTP id 206F56B0033 for ; Sat, 4 Nov 2017 05:55:36 -0400 (EDT) Received: by mail-ua0-f198.google.com with SMTP id e46so3060153uaa.6 for ; Sat, 04 Nov 2017 02:55:36 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id k2sor2868687uad.249.2017.11.04.02.55.35 for (Google Transport Security); Sat, 04 Nov 2017 02:55:35 -0700 (PDT) MIME-Version: 1.0 From: Maxim Levitsky Date: Sat, 4 Nov 2017 11:55:14 +0200 Message-ID: Subject: Guaranteed allocation of huge pages (1G) using movablecore=N doesn't seem to work at all Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: LKML Cc: linux-mm@kvack.org Hi! My system has 64G of ram and I want to create 32 1G huge pages to use in KVM virtualization, on demand, only when VM is running. So I booted the kernel with 'hugepagesz=1G hugepages=0 default_hugepagesz=1G movablecore=40G' However I still can't allocate the pages reliably. For instance this simple script is enough to make it not possible to even allocate one 1G huge page after few dozens of iterations: while true ; do sudo hugeadm --enable-zone-movable --pool-pages-min 1G:0G sudo hugeadm --enable-zone-movable --pool-pages-min 1G:60G done I disabled mlock systemwide (now ulimit -l shows 0), I still see 8 pages mlocked in zone 'Movable' but this is not enough to explain this nr_mlock 8 I do have around 64GB of swap too, but I see no even an attempt to use it. # free total used free shared buff/cache available Mem: 65887928 1748344 62640276 61688 1499308 62053832 Swap: 67108860 0 67108860 Any idea about what is going on? This was tested on 4.14.0-rc5 (my custom compiled) and on several older kernels (4.10,4.12,4.13) from ubuntu repositories. Disabling/enabling transparent huge pages in the kernel config didn't make a difference. VT-d was enabled during the tests (intel_iommu=on,igfx_off) if that would make any difference, but no VM was started when I run the above script, in fact I run it just after the system booted. Best regards, Maxim Levitsky -- 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