From: Dan Williams <dan.j.williams@intel.com>
To: David Hildenbrand <david@redhat.com>
Cc: Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-ia64@vger.kernel.org,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-s390 <linux-s390@vger.kernel.org>,
Linux-sh <linux-sh@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Alex Deucher <alexander.deucher@amd.com>,
"David S. Miller" <davem@davemloft.net>,
Mark Brown <broonie@kernel.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Oscar Salvador <osalvador@suse.de>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: Re: [PATCH v2 7/8] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail
Date: Tue, 7 May 2019 17:15:17 -0700 [thread overview]
Message-ID: <CAPcyv4h2PgzQZrD0UU=4Qz_yH2C_hiYQyqV9U7CCkjpmHZ5xjQ@mail.gmail.com> (raw)
In-Reply-To: <20190507183804.5512-8-david@redhat.com>
On Tue, May 7, 2019 at 11:39 AM David Hildenbrand <david@redhat.com> wrote:
>
> We really don't want anything during memory hotunplug to fail.
> We always pass a valid memory block device, that check can go. Avoid
> allocating memory and eventually failing. As we are always called under
> lock, we can use a static piece of memory. This avoids having to put
> the structure onto the stack, having to guess about the stack size
> of callers.
>
> Patch inspired by a patch from Oscar Salvador.
>
> In the future, there might be no need to iterate over nodes at all.
> mem->nid should tell us exactly what to remove. Memory block devices
> with mixed nodes (added during boot) should properly fenced off and never
> removed.
>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> drivers/base/node.c | 18 +++++-------------
> include/linux/node.h | 5 ++---
> 2 files changed, 7 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 04fdfa99b8bc..9be88fd05147 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -803,20 +803,14 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
>
> /*
> * Unregister memory block device under all nodes that it spans.
> + * Has to be called with mem_sysfs_mutex held (due to unlinked_nodes).
Given this comment can bitrot relative to the implementation lets
instead add an explicit:
lockdep_assert_held(&mem_sysfs_mutex);
With that you can add:
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
next prev parent reply other threads:[~2019-05-08 0:15 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-07 18:37 [PATCH v2 0/8] mm/memory_hotplug: Factor out memory block device handling David Hildenbrand
2019-05-07 18:37 ` [PATCH v2 1/8] mm/memory_hotplug: Simplify and fix check_hotplug_memory_range() David Hildenbrand
2019-05-07 20:38 ` Dan Williams
2019-05-09 12:23 ` Wei Yang
2019-05-07 18:37 ` [PATCH v2 2/8] s390x/mm: Implement arch_remove_memory() David Hildenbrand
2019-05-07 20:46 ` Dan Williams
2019-05-07 20:47 ` David Hildenbrand
2019-05-07 20:57 ` Dan Williams
2019-05-07 21:13 ` David Hildenbrand
2019-05-07 18:37 ` [PATCH v2 3/8] mm/memory_hotplug: arch_remove_memory() and __remove_pages() with CONFIG_MEMORY_HOTPLUG David Hildenbrand
2019-05-07 21:02 ` Dan Williams
2019-05-07 21:06 ` David Hildenbrand
2019-05-13 7:48 ` David Hildenbrand
2019-05-13 8:20 ` David Hildenbrand
2019-05-07 18:38 ` [PATCH v2 4/8] mm/memory_hotplug: Create memory block devices after arch_add_memory() David Hildenbrand
2019-05-07 21:17 ` Dan Williams
2019-05-07 21:27 ` David Hildenbrand
2019-05-08 8:35 ` David Hildenbrand
2019-05-09 12:43 ` Wei Yang
2019-05-09 12:50 ` David Hildenbrand
2019-05-09 13:55 ` Wei Yang
2019-05-09 14:05 ` David Hildenbrand
2019-05-09 14:31 ` Wei Yang
2019-05-09 14:58 ` David Hildenbrand
2019-05-09 21:50 ` Wei Yang
2019-05-09 22:18 ` David Hildenbrand
2019-05-07 18:38 ` [PATCH v2 5/8] mm/memory_hotplug: Drop MHP_MEMBLOCK_API David Hildenbrand
2019-05-07 21:19 ` Dan Williams
2019-05-07 21:24 ` David Hildenbrand
2019-05-07 21:25 ` Dan Williams
2019-05-08 7:39 ` David Hildenbrand
2019-05-08 23:08 ` osalvador
2019-05-09 7:05 ` David Hildenbrand
2019-05-07 18:38 ` [PATCH v2 6/8] mm/memory_hotplug: Remove memory block devices before arch_remove_memory() David Hildenbrand
2019-05-07 21:27 ` Dan Williams
2019-05-07 18:38 ` [PATCH v2 7/8] mm/memory_hotplug: Make unregister_memory_block_under_nodes() never fail David Hildenbrand
2019-05-08 0:15 ` Dan Williams [this message]
2019-05-08 7:21 ` David Hildenbrand
2019-05-08 13:50 ` Dan Williams
2019-05-07 18:38 ` [PATCH v2 8/8] mm/memory_hotplug: Remove "zone" parameter from sparse_remove_one_section David Hildenbrand
2019-05-08 0:30 ` Dan Williams
2019-05-07 19:04 ` [PATCH v2 0/8] mm/memory_hotplug: Factor out memory block device handling Dan Williams
2019-05-07 19:21 ` David Hildenbrand
2019-05-07 19:37 ` David Hildenbrand
2019-05-07 20:36 ` Dan Williams
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