From: Christopher Lameter <cl@linux.com>
To: Qian Cai <cai@lca.pw>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
fabecassis@nvidia.com, jhubbard@nvidia.com, mhocko@suse.com,
vbabka@suse.cz, mgorman@techsingularity.net,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [v2 PATCH] mm: move_pages: return valid node id in status if the page is already on the target node
Date: Thu, 5 Dec 2019 18:17:28 +0000 (UTC) [thread overview]
Message-ID: <alpine.DEB.2.21.1912051815100.9722@www.lameter.com> (raw)
In-Reply-To: <1707CDD0-E05E-411A-A093-35E8E50ACA4B@lca.pw>
[-- Attachment #1: Type: text/plain, Size: 870 bytes --]
On Thu, 5 Dec 2019, Qian Cai wrote:
> > On Dec 5, 2019, at 12:39 PM, Yang Shi <yang.shi@linux.alibaba.com> wrote:
> >
> > There are definitely a few inconsistencies, but I think the manpage is quite clear for this specific case, which says "status is an array of integers that return the status of each page. The array contains valid values only if move_pages() did not return an error." And, it looks kernel just misbehaved since 4.17 due to the fixes commit, so it sounds like a regression too.
>
> “Only if” in strictly logical term does not necessarily mean it must contain valid values if move_pages() succeed.
The intended meaning is that valid values in the status array are provided
when the syscall succeeds and not otherwise. In the error case there may
be some valid values but since the operation may have aborted not all
values may have a value.
next prev parent reply other threads:[~2019-12-05 18:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-05 4:21 [v2 PATCH] mm: move_pages: return valid node id in status if the page is already on the target node Yang Shi
2019-12-05 5:44 ` John Hubbard
2019-12-05 5:50 ` John Hubbard
2019-12-05 17:20 ` Yang Shi
2019-12-05 9:42 ` Qian Cai
2019-12-05 17:39 ` Yang Shi
2019-12-05 18:11 ` Qian Cai
2019-12-05 18:17 ` Christopher Lameter [this message]
2019-12-05 11:31 ` Michal Hocko
2019-12-05 17:18 ` Yang Shi
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