From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yisheng Xie Subject: Re: [PATCH RFC v2 4/4] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages Date: Tue, 7 Nov 2017 19:23:52 +0800 Message-ID: References: <1509099265-30868-1-git-send-email-xieyisheng1@huawei.com> <1509099265-30868-5-git-send-email-xieyisheng1@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christopher Lameter , Vlastimil Babka Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, mhocko-IBi9RG/b67k@public.gmane.org, mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, n-horiguchi-PaJj6Psr51x8UrSeD/g0lQ@public.gmane.org, salls-b3bnyZ7c9ISVc3sceRu5cw@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tanxiaojun-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andi Kleen List-Id: linux-api@vger.kernel.org hi Christopher and Vlastimil, Thanks for your comment! On 2017/11/6 23:29, Christopher Lameter wrote: > On Mon, 6 Nov 2017, Vlastimil Babka wrote: > >> I'm not sure what exactly is the EPERM intention. Should really the >> capability of THIS process override the cpuset restriction of the TARGET >> process? Maybe yes. Then, does "insufficient privilege (CAP_SYS_NICE) to > > CAP_SYS_NICE never overrides cpuset restrictions. The cap can be used to > migrate pages that are *also* mapped by other processes (and thus move > pages of another process which may have different cpu set restrictions!). So you means the specified nodes should be a subset of target cpu set, right? Thanks Yisheng Xie > The cap should not allow migrating pages to nodes that are not allowed by > the cpuset of the current process. > > > > . >