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From: David Hildenbrand <david@redhat.com>
To: linux-mm@kvack.org
Cc: David Hildenbrand <david@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
	Mel Gorman <mgorman@techsingularity.net>,
	Pavel Tatashin <pasha.tatashin@oracle.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	Ingo Molnar <mingo@kernel.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH RFC 5/8] mm: only mark section offline when all pages are offline
Date: Fri, 13 Apr 2018 15:33:06 +0200	[thread overview]
Message-ID: <20180413133309.3501-1-david@redhat.com> (raw)
In-Reply-To: <20180413131632.1413-1-david@redhat.com>

If any page is still online, the section should stay online.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/page_alloc.c |  2 +-
 mm/sparse.c     | 25 ++++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2e5dcfdb0908..ae9023da2ca2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8013,7 +8013,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 			break;
 	if (pfn == end_pfn)
 		return;
-	offline_mem_sections(pfn, end_pfn);
 	zone = page_zone(pfn_to_page(pfn));
 	spin_lock_irqsave(&zone->lock, flags);
 	pfn = start_pfn;
@@ -8051,6 +8050,7 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 		pfn += (1 << order);
 	}
 	spin_unlock_irqrestore(&zone->lock, flags);
+	offline_mem_sections(start_pfn, end_pfn);
 }
 #endif
 
diff --git a/mm/sparse.c b/mm/sparse.c
index 58cab483e81b..44978cb18fed 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -623,7 +623,27 @@ void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 }
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
-/* Mark all memory sections within the pfn range as online */
+static bool all_pages_in_section_offline(unsigned long section_nr)
+{
+	unsigned long pfn = section_nr_to_pfn(section_nr);
+	struct page *page;
+	int i;
+
+	for (i = 0; i < PAGES_PER_SECTION; i++, pfn++) {
+		if (!pfn_valid(pfn))
+			continue;
+
+		page = pfn_to_page(pfn);
+		if (!PageOffline(page))
+			return false;
+	}
+	return true;
+}
+
+/*
+ * Mark all memory sections within the pfn range as offline (if all pages
+ * of a memory section are already offline)
+ */
 void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 {
 	unsigned long pfn;
@@ -639,6 +659,9 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 		if (WARN_ON(!valid_section_nr(section_nr)))
 			continue;
 
+		if (!all_pages_in_section_offline(section_nr))
+			continue;
+
 		ms = __nr_to_section(section_nr);
 		ms->section_mem_map &= ~SECTION_IS_ONLINE;
 	}
-- 
2.14.3

  parent reply	other threads:[~2018-04-13 13:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20180413131632.1413-1-david@redhat.com>
2018-04-13 13:16 ` [PATCH RFC 1/8] mm/memory_hotplug: Revert "mm/memory_hotplug: optimize memory hotplug" David Hildenbrand
2018-04-13 13:16 ` [PATCH RFC 2/8] mm: introduce PG_offline David Hildenbrand
2018-04-13 13:40   ` Michal Hocko
2018-04-13 13:46     ` David Hildenbrand
2018-04-17 11:50     ` David Hildenbrand
2018-04-13 17:11   ` Matthew Wilcox
2018-04-16  8:31     ` David Hildenbrand
2018-04-21 16:52     ` Vlastimil Babka
2018-04-22  3:01       ` Matthew Wilcox
2018-04-22  8:17         ` David Hildenbrand
2018-04-22 14:02           ` Matthew Wilcox
2018-04-22 15:13             ` David Hildenbrand
2018-04-29 21:08               ` Michal Hocko
2018-04-30  6:31                 ` David Hildenbrand
2018-04-20  7:30   ` David Hildenbrand
2018-04-13 13:16 ` [PATCH RFC 3/8] mm: use PG_offline in online/offlining code David Hildenbrand
2018-04-13 13:31 ` [PATCH RFC 4/8] kdump: expose PG_offline David Hildenbrand
2018-04-13 13:33 ` David Hildenbrand [this message]
2018-04-13 13:33 ` [PATCH RFC 6/8] mm: offline_pages() is also limited by MAX_ORDER David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 7/8] mm: allow to control onlining/offlining of memory by a driver David Hildenbrand
2018-04-13 15:59   ` Michal Hocko
2018-04-13 16:32     ` David Hildenbrand
2018-04-13 13:33 ` [PATCH RFC 8/8] mm: export more functions used to online/offline memory David Hildenbrand
2018-04-13 13:32 [PATCH RFC 5/8] mm: only mark section offline when all pages are offline David Hildenbrand
2018-04-13 13:42 ` David Hildenbrand

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