From: Vlastimil Babka <vbabka@suse.cz>
To: Christopher Lameter <cl@linux.com>, Yisheng Xie <xieyisheng1@huawei.com>
Cc: akpm@linux-foundation.org, mhocko@suse.com, mingo@kernel.org,
rientjes@google.com, n-horiguchi@ah.jp.nec.com,
salls@cs.ucsb.edu, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, tanxiaojun@huawei.com,
linux-api@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH RFC v2 4/4] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages
Date: Tue, 7 Nov 2017 16:05:10 +0100 [thread overview]
Message-ID: <04e4cb50-8cba-58af-1a5e-61e818cffa70@suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.20.1711070851560.18776@nuc-kabylake>
On 11/07/2017 03:54 PM, Christopher Lameter wrote:
> On Tue, 7 Nov 2017, Yisheng Xie wrote:
>
>> 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?
>
> The specified nodes need to be part of the *current* cpu set.
>
> Migrate pages moves the pages of a single process there is no TARGET
> process.
migrate_pages(2) takes a pid argument
"migrate_pages() attempts to move all pages of the process pid that
are in memory nodes old_nodes to the memory nodes in new_nodes. "
> Thus thehe *target* nodes need to be a subset of the current cpu set.
>
>
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next prev parent reply other threads:[~2017-11-07 15:05 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-27 10:14 [PATCH RFC v2 0/4] some fixes and clean up for mempolicy Yisheng Xie
2017-10-27 10:14 ` [PATCH RFC v2 1/4] mm/mempolicy: Fix get_nodes() mask miscalculation Yisheng Xie
2017-10-31 8:34 ` Vlastimil Babka
2017-11-01 9:37 ` Yisheng Xie
2017-10-27 10:14 ` [PATCH RFC v2 2/4] mm/mempolicy: remove redundant check in get_nodes Yisheng Xie
2017-10-31 8:55 ` Vlastimil Babka
2017-10-27 10:14 ` [PATCH RFC v2 3/4] mm/mempolicy: fix the check of nodemask from user Yisheng Xie
2017-10-31 9:30 ` Vlastimil Babka
2017-10-31 11:01 ` Yisheng Xie
2017-10-31 11:28 ` Vlastimil Babka
2017-10-27 10:14 ` [PATCH RFC v2 4/4] mm/mempolicy: add nodes_empty check in SYSC_migrate_pages Yisheng Xie
2017-10-31 9:46 ` Vlastimil Babka
2017-11-06 1:31 ` Yisheng Xie
2017-11-06 7:39 ` Vlastimil Babka
2017-11-06 15:29 ` Christopher Lameter
2017-11-07 11:23 ` Yisheng Xie
2017-11-07 14:54 ` Christopher Lameter
2017-11-07 15:05 ` Vlastimil Babka [this message]
2017-11-07 15:55 ` Christopher Lameter
2017-11-08 1:38 ` Yisheng Xie
2017-11-08 15:02 ` Christopher Lameter
2017-11-09 10:54 ` Yisheng Xie
2017-11-09 15:46 ` Christopher Lameter
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