From: Oscar Salvador <osalvador@suse.de>
To: David Hildenbrand <david@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Vlastimil Babka <vbabka@suse.cz>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 2/8] mm,memory_hotplug: Relax fully spanned sections check
Date: Wed, 7 Apr 2021 09:42:53 +0200 [thread overview]
Message-ID: <20210407074249.GA9353@linux> (raw)
In-Reply-To: <59A04B1D-08D6-4E71-A382-F5503A6E0AF7@redhat.com>
On Tue, Apr 06, 2021 at 10:43:01PM +0200, David Hildenbrand wrote:
> But not end_pfn as given in my version or what am I missing?
Nah, was my fault, I managed to see:
if (WARN_ON_ONCE(!nr_pages ||
!IS_ALIGNED(start_pfn, pageblock_nr_pages))
!IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION)))
which would not work.
I agree that keeping the PAGES_PER_SECTION check maks this safer, so this all
should have been:
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0cdbbfbc5757..25e59d5dc13c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -838,9 +838,14 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
int ret;
struct memory_notify arg;
- /* We can only online full sections (e.g., SECTION_IS_ONLINE) */
+ /* We can only offline full sections (e.g., SECTION_IS_ONLINE).
+ * However, when using e.g: memmap_on_memory, some pages are initialized
+ * prior to calling in here. The remaining amount of pages must be
+ * pageblock aligned.
+ */
if (WARN_ON_ONCE(!nr_pages ||
- !IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION)))
+ !IS_ALIGNED(pfn, pageblock_nr_pages) ||
+ !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
@@ -1573,9 +1578,14 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages)
int ret, node;
char *reason;
- /* We can only offline full sections (e.g., SECTION_IS_ONLINE) */
+ /* We can only offline full sections (e.g., SECTION_IS_ONLINE).
+ * However, when using e.g: memmap_on_memory, some pages are initialized
+ * prior to calling in here. The remaining amount of pages must be
+ * pageblock aligned.
+ */
if (WARN_ON_ONCE(!nr_pages ||
- !IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION)))
+ !IS_ALIGNED(start_pfn, pageblock_nr_pages) ||
+ !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
return -EINVAL;
mem_hotplug_begin();
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-04-07 7:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210406111115.8953-1-osalvador@suse.de>
2021-04-06 11:11 ` [PATCH v6 1/8] drivers/base/memory: Introduce memory_block_{online,offline} Oscar Salvador
2021-04-06 11:11 ` [PATCH v6 2/8] mm,memory_hotplug: Relax fully spanned sections check Oscar Salvador
2021-04-06 15:32 ` David Hildenbrand
2021-04-06 16:33 ` Oscar Salvador
2021-04-06 20:43 ` David Hildenbrand
2021-04-07 7:42 ` Oscar Salvador [this message]
2021-04-07 7:43 ` David Hildenbrand
2021-04-06 11:11 ` [PATCH v6 3/8] mm,memory_hotplug: Factor out adjusting present pages into adjust_present_page_count() Oscar Salvador
2021-04-06 15:33 ` David Hildenbrand
2021-04-07 7:11 ` Oscar Salvador
2021-04-06 11:11 ` [PATCH v6 5/8] acpi,memhotplug: Enable MHP_MEMMAP_ON_MEMORY when supported Oscar Salvador
2021-04-06 11:11 ` [PATCH v6 6/8] mm,memory_hotplug: Add kernel boot option to enable memmap_on_memory Oscar Salvador
2021-04-06 11:11 ` [PATCH v6 7/8] x86/Kconfig: Introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE Oscar Salvador
2021-04-06 11:11 ` [PATCH v6 8/8] arm64/Kconfig: " Oscar Salvador
[not found] ` <20210406111115.8953-5-osalvador@suse.de>
2021-04-06 17:10 ` [PATCH v6 4/8] mm,memory_hotplug: Allocate memmap from the added memory range kernel test robot
2021-04-06 20:28 ` Oscar Salvador
2021-04-07 20:38 ` Oscar Salvador
2021-04-09 5:05 ` Andrew Morton
2021-04-09 5:10 ` Oscar Salvador
2021-04-09 8:10 ` David Hildenbrand
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