From: Zi Yan <zi.yan@sent.com>
To: David Hildenbrand <david@redhat.com>, Oscar Salvador <osalvador@suse.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mike Rapoport <rppt@kernel.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Michal Hocko <mhocko@suse.com>,
Dan Williams <dan.j.williams@intel.com>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org,
Zi Yan <ziy@nvidia.com>
Subject: [RFC PATCH 1/7] mm: sparse: set/clear subsection bitmap when pages are onlined/offlined.
Date: Thu, 6 May 2021 11:26:17 -0400 [thread overview]
Message-ID: <20210506152623.178731-2-zi.yan@sent.com> (raw)
In-Reply-To: <20210506152623.178731-1-zi.yan@sent.com>
From: Zi Yan <ziy@nvidia.com>
subsection bitmap was set/cleared when a section is added/removed, but
pfn_to_online_page() uses subsection bitmap to check if the page is
online, which is not accurate. It was working when a whole section is
added/removed during memory hotplug and hotremove. When the following
patches enable memory hotplug and hotremove for subsections,
subsection bitmap needs to be changed during page online/offline time,
otherwise, pfn_to_online_page() will not give right answers. Move the
subsection bitmap manipulation code from section_activate() to
online_mem_sections() and section_deactivate() to
offline_mem_sections(), respectively.
Signed-off-by: Zi Yan <ziy@nvidia.com>
---
mm/sparse.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)
diff --git a/mm/sparse.c b/mm/sparse.c
index b2ada9dc00cb..7637208b8874 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -606,6 +606,7 @@ void __init sparse_init(void)
#ifdef CONFIG_MEMORY_HOTPLUG
+static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages);
/* Mark all memory sections within the pfn range as online */
void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
{
@@ -621,9 +622,12 @@ void online_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
ms = __nr_to_section(section_nr);
ms->section_mem_map |= SECTION_IS_ONLINE;
+ fill_subsection_map(pfn, min(end_pfn, pfn + PAGES_PER_SECTION) - pfn);
}
}
+static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages);
+static bool is_subsection_map_empty(struct mem_section *ms);
/* Mark all memory sections within the pfn range as offline */
void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
{
@@ -641,7 +645,13 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
continue;
ms = __nr_to_section(section_nr);
- ms->section_mem_map &= ~SECTION_IS_ONLINE;
+
+ if (end_pfn < pfn + PAGES_PER_SECTION) {
+ clear_subsection_map(pfn, end_pfn - pfn);
+ if (is_subsection_map_empty(ms))
+ ms->section_mem_map &= ~SECTION_IS_ONLINE;
+ } else
+ ms->section_mem_map &= ~SECTION_IS_ONLINE;
}
}
@@ -668,6 +678,17 @@ static void free_map_bootmem(struct page *memmap)
vmemmap_free(start, end, NULL);
}
+static int subsection_map_intersects(struct mem_section *ms, unsigned long pfn,
+ unsigned long nr_pages)
+{
+ DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
+ unsigned long *subsection_map = &ms->usage->subsection_map[0];
+
+ subsection_mask_set(map, pfn, nr_pages);
+
+ return bitmap_intersects(map, subsection_map, SUBSECTIONS_PER_SECTION);
+}
+
static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
{
DECLARE_BITMAP(map, SUBSECTIONS_PER_SECTION) = { 0 };
@@ -760,6 +781,12 @@ static void free_map_bootmem(struct page *memmap)
}
}
+static int subsection_map_intersects(struct mem_section *ms, unsigned long pfn,
+ unsigned long nr_pages)
+{
+ return 0;
+}
+
static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages)
{
return 0;
@@ -800,7 +827,10 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
struct page *memmap = NULL;
bool empty;
- if (clear_subsection_map(pfn, nr_pages))
+ if (WARN((IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) && !ms->usage) ||
+ subsection_map_intersects(ms, pfn, nr_pages),
+ "section already deactivated (%#lx + %ld)\n",
+ pfn, nr_pages))
return;
empty = is_subsection_map_empty(ms);
@@ -855,7 +885,7 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
ms->usage = usage;
}
- rc = fill_subsection_map(pfn, nr_pages);
+ rc = !nr_pages || subsection_map_intersects(ms, pfn, nr_pages);
if (rc) {
if (usage)
ms->usage = NULL;
--
2.30.2
next prev parent reply other threads:[~2021-05-06 15:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 15:26 [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size Zi Yan
2021-05-06 15:26 ` Zi Yan [this message]
2021-05-06 17:48 ` [RFC PATCH 1/7] mm: sparse: set/clear subsection bitmap when pages are onlined/offlined David Hildenbrand
2021-05-06 19:03 ` Zi Yan
2021-05-06 19:14 ` David Hildenbrand
2021-05-06 15:26 ` [RFC PATCH 2/7] mm: set pageblock_order to the max of HUGETLB_PAGE_ORDER and MAX_ORDER-1 Zi Yan
2021-05-06 15:26 ` [RFC PATCH 3/7] mm: memory_hotplug: decouple memory_block size with section size Zi Yan
2021-05-06 15:26 ` [RFC PATCH 4/7] mm: pageblock: allow set/unset migratetype for partial pageblock Zi Yan
2021-05-06 15:26 ` [RFC PATCH 5/7] mm: memory_hotplug, sparse: enable memory hotplug/hotremove subsections Zi Yan
2021-05-06 15:26 ` [RFC PATCH 6/7] arch: x86: no MAX_ORDER exceeds SECTION_SIZE check for 32bit vdso Zi Yan
2021-05-06 15:26 ` [RFC PATCH 7/7] [not for merge] mm: increase SECTION_SIZE_BITS to 31 Zi Yan
2021-05-06 15:31 ` [RFC PATCH 0/7] Memory hotplug/hotremove at subsection size David Hildenbrand
2021-05-06 15:37 ` Zi Yan
2021-05-06 15:40 ` David Hildenbrand
2021-05-06 15:50 ` Zi Yan
2021-05-06 16:28 ` David Hildenbrand
2021-05-06 18:49 ` Zi Yan
2021-05-06 19:10 ` David Hildenbrand
2021-05-06 19:30 ` Matthew Wilcox
2021-05-06 19:38 ` David Hildenbrand
2021-05-06 15:38 ` David Hildenbrand
2021-05-07 11:55 ` Michal Hocko
2021-05-07 14:00 ` David Hildenbrand
2021-05-10 14:36 ` Zi Yan
2021-05-12 16:14 ` David Hildenbrand
2021-06-02 15:56 ` Zi Yan
2021-06-14 11:32 ` David Hildenbrand
2021-05-06 15:42 ` Zi Yan
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