From: Matthew Wilcox <willy@infradead.org>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <ak@linux.intel.com>, Christoph Lameter <cl@linux.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
David Hildenbrand <david@redhat.com>,
Suren Baghdasaryan <surenb@google.com>,
Yang Shi <shy828301@gmail.com>,
Sidhartha Kumar <sidhartha.kumar@oracle.com>,
Vishal Moola <vishal.moola@gmail.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Tejun Heo <tj@kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@suse.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 02/12] kernfs: drop shared NUMA mempolicy hooks
Date: Mon, 25 Sep 2023 23:10:48 +0100 [thread overview]
Message-ID: <ZRIFaPsEHTIxEY/d@casper.infradead.org> (raw)
In-Reply-To: <dffc667-5dc9-a980-dab8-8554eafbda7@google.com>
On Mon, Sep 25, 2023 at 01:22:27AM -0700, Hugh Dickins wrote:
> It seems strange that kernfs should be an outlier with a set_policy and
> get_policy in its kernfs_vm_ops. Ah, it dates back to v2.6.30's commit
> 095160aee954 ("sysfs: fix some bin_vm_ops errors"), when I had crashed
> on powerpc's pci_mmap_legacy_page_range() fallback to shmem_zero_setup().
>
> Well, that was commendably thorough, to give sysfs-bin a set_policy and
> get_policy, just to avoid the way it was coded resulting in EINVAL from
> mmap when CONFIG_NUMA; but somehow feels a bit over-the-top to me now.
>
> It's easier to say that nobody should expect to manage a shmem object's
> shared NUMA mempolicy via some kernfs backdoor to that object: delete
> that code (and there's no longer an EINVAL from mmap in the NUMA case).
>
> This then leaves set_policy/get_policy as implemented only by shmem -
> though importantly also by SysV SHM, which has to interface with shmem
> which implements them, and with SHM_HUGETLB which does not.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
next prev parent reply other threads:[~2023-09-25 22:11 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-25 8:17 [PATCH 00/12] mempolicy: cleanups leading to NUMA mpol without vma Hugh Dickins
2023-09-25 8:21 ` [PATCH 01/12] hugetlbfs: drop shared NUMA mempolicy pretence Hugh Dickins
2023-09-25 22:09 ` Matthew Wilcox
2023-09-25 22:46 ` Andi Kleen
2023-09-26 22:26 ` Hugh Dickins
2023-09-25 8:22 ` [PATCH 02/12] kernfs: drop shared NUMA mempolicy hooks Hugh Dickins
2023-09-25 22:10 ` Matthew Wilcox [this message]
2023-09-25 8:24 ` [PATCH 03/12] mempolicy: fix migrate_pages(2) syscall return nr_failed Hugh Dickins
2023-09-25 22:22 ` Matthew Wilcox
2023-09-26 20:47 ` Hugh Dickins
2023-09-27 8:02 ` Huang, Ying
2023-09-30 4:20 ` Hugh Dickins
2023-09-25 8:25 ` [PATCH 04/12] mempolicy trivia: delete those ancient pr_debug()s Hugh Dickins
2023-09-25 22:23 ` Matthew Wilcox
2023-09-25 8:26 ` [PATCH 05/12] mempolicy trivia: slightly more consistent naming Hugh Dickins
2023-09-25 22:28 ` Matthew Wilcox
2023-09-25 8:28 ` [PATCH 06/12] mempolicy trivia: use pgoff_t in shared mempolicy tree Hugh Dickins
2023-09-25 22:31 ` Matthew Wilcox
2023-09-25 22:38 ` Matthew Wilcox
2023-09-26 21:19 ` Hugh Dickins
2023-09-25 8:29 ` [PATCH 07/12] mempolicy: mpol_shared_policy_init() without pseudo-vma Hugh Dickins
2023-09-25 22:50 ` Matthew Wilcox
2023-09-26 21:36 ` Hugh Dickins
2023-09-25 8:30 ` [PATCH 08/12] mempolicy: remove confusing MPOL_MF_LAZY dead code Hugh Dickins
2023-09-25 22:52 ` Matthew Wilcox
2023-09-25 8:32 ` [PATCH 09/12] mm: add page_rmappable_folio() wrapper Hugh Dickins
2023-09-25 22:58 ` Matthew Wilcox
2023-09-26 21:58 ` Hugh Dickins
2023-09-25 8:33 ` [PATCH 10/12] mempolicy: alloc_pages_mpol() for NUMA policy without vma Hugh Dickins
2023-09-25 8:35 ` [PATCH 11/12] mempolicy: mmap_lock is not needed while migrating folios Hugh Dickins
2023-09-25 8:36 ` [PATCH 12/12] mempolicy: migration attempt to match interleave nodes Hugh Dickins
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