From: David Hildenbrand <david@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@suse.com>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Dan Williams <dan.j.williams@intel.com>
Subject: [PATCH v2 2/5] mm/memory_hotplug: Drop PageReserved() check in online_pages_range()
Date: Wed, 14 Aug 2019 17:41:06 +0200 [thread overview]
Message-ID: <20190814154109.3448-3-david@redhat.com> (raw)
In-Reply-To: <20190814154109.3448-1-david@redhat.com>
move_pfn_range_to_zone() will set all pages to PG_reserved via
memmap_init_zone(). The only way a page could no longer be reserved
would be if a MEM_GOING_ONLINE notifier would clear PG_reserved - which
is not done (the online_page callback is used for that purpose by
e.g., Hyper-V instead). walk_system_ram_range() will never call
online_pages_range() with duplicate PFNs, so drop the PageReserved() check.
This seems to be a leftover from ancient times where the memmap was
initialized when adding memory and we wanted to check for already
onlined memory.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
mm/memory_hotplug.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 3706a137d880..10ad970f3f14 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -653,9 +653,7 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
{
unsigned long onlined_pages = *(unsigned long *)arg;
- if (PageReserved(pfn_to_page(start_pfn)))
- onlined_pages += online_pages_blocks(start_pfn, nr_pages);
-
+ onlined_pages += online_pages_blocks(start_pfn, nr_pages);
online_mem_sections(start_pfn, start_pfn + nr_pages);
*(unsigned long *)arg = onlined_pages;
--
2.21.0
next prev parent reply other threads:[~2019-08-14 15:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 15:41 [PATCH v2 0/5] mm/memory_hotplug: online_pages() cleanups David Hildenbrand
2019-08-14 15:41 ` [PATCH v2 1/5] resource: Use PFN_UP / PFN_DOWN in walk_system_ram_range() David Hildenbrand
2019-08-14 16:15 ` Wei Yang
2019-08-14 15:41 ` David Hildenbrand [this message]
2019-08-14 16:04 ` [PATCH v2 2/5] mm/memory_hotplug: Drop PageReserved() check in online_pages_range() Michal Hocko
2019-08-14 15:41 ` [PATCH v2 3/5] mm/memory_hotplug: Simplify online_pages_range() David Hildenbrand
2019-08-14 16:07 ` Michal Hocko
2019-08-14 15:41 ` [PATCH v2 4/5] mm/memory_hotplug: Make sure the pfn is aligned to the order when onlining David Hildenbrand
2019-08-14 16:09 ` David Hildenbrand
2019-08-14 18:32 ` Michal Hocko
2019-08-14 19:04 ` David Hildenbrand
2019-08-14 20:56 ` Andrew Morton
2019-08-14 21:47 ` David Hildenbrand
2019-08-14 22:10 ` Andrew Morton
2019-08-14 15:41 ` [PATCH v2 5/5] mm/memory_hotplug: online_pages cannot be 0 in online_pages() David Hildenbrand
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