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authorMichal Hocko <mhocko@suse.com>2017-07-06 15:38:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-06 16:24:32 -0700
commitf1dd2cd13c4bbbc9a7c4617b3b034fa643de98fe (patch)
tree0d2a224cf6ae6ed6da10070c8503ab0fa4d1878a /mm/memory_hotplug.c
parentd336e94e448a514607551026f0624329b6af52c5 (diff)
downloadlinux-f1dd2cd13c4bbbc9a7c4617b3b034fa643de98fe.tar.bz2
mm, memory_hotplug: do not associate hotadded memory to zones until online
The current memory hotplug implementation relies on having all the struct pages associate with a zone/node during the physical hotplug phase (arch_add_memory->__add_pages->__add_section->__add_zone). In the vast majority of cases this means that they are added to ZONE_NORMAL. This has been so since 9d99aaa31f59 ("[PATCH] x86_64: Support memory hotadd without sparsemem") and it wasn't a big deal back then because movable onlining didn't exist yet. Much later memory hotplug wanted to (ab)use ZONE_MOVABLE for movable onlining 511c2aba8f07 ("mm, memory-hotplug: dynamic configure movable memory and portion memory") and then things got more complicated. Rather than reconsidering the zone association which was no longer needed (because the memory hotplug already depended on SPARSEMEM) a convoluted semantic of zone shifting has been developed. Only the currently last memblock or the one adjacent to the zone_movable can be onlined movable. This essentially means that the online type changes as the new memblocks are added. Let's simulate memory hot online manually $ echo 0x100000000 > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory32/valid_zones Normal Movable $ echo $((0x100000000+(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable $ echo $((0x100000000+2*(128<<20))) > /sys/devices/system/memory/probe $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal /sys/devices/system/memory/memory34/valid_zones:Normal Movable $ echo online_movable > /sys/devices/system/memory/memory34/state $ grep . /sys/devices/system/memory/memory3?/valid_zones /sys/devices/system/memory/memory32/valid_zones:Normal /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Normal This is an awkward semantic because an udev event is sent as soon as the block is onlined and an udev handler might want to online it based on some policy (e.g. association with a node) but it will inherently race with new blocks showing up. This patch changes the physical online phase to not associate pages with any zone at all. All the pages are just marked reserved and wait for the onlining phase to be associated with the zone as per the online request. There are only two requirements - existing ZONE_NORMAL and ZONE_MOVABLE cannot overlap - ZONE_NORMAL precedes ZONE_MOVABLE in physical addresses the latter one is not an inherent requirement and can be changed in the future. It preserves the current behavior and made the code slightly simpler. This is subject to change in future. This means that the same physical online steps as above will lead to the following state: Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Normal Movable /sys/devices/system/memory/memory32/valid_zones:Normal Movable /sys/devices/system/memory/memory33/valid_zones:Normal Movable /sys/devices/system/memory/memory34/valid_zones:Movable Implementation: The current move_pfn_range is reimplemented to check the above requirements (allow_online_pfn_range) and then updates the respective zone (move_pfn_range_to_zone), the pgdat and links all the pages in the pfn range with the zone/node. __add_pages is updated to not require the zone and only initializes sections in the range. This allowed to simplify the arch_add_memory code (s390 could get rid of quite some of code). devm_memremap_pages is the only user of arch_add_memory which relies on the zone association because it only hooks into the memory hotplug only half way. It uses it to associate the new memory with ZONE_DEVICE but doesn't allow it to be {on,off}lined via sysfs. This means that this particular code path has to call move_pfn_range_to_zone explicitly. The original zone shifting code is kept in place and will be removed in the follow up patch for an easier review. Please note that this patch also changes the original behavior when offlining a memory block adjacent to another zone (Normal vs. Movable) used to allow to change its movable type. This will be handled later. [richard.weiyang@gmail.com: simplify zone_intersects()] Link: http://lkml.kernel.org/r/20170616092335.5177-1-richard.weiyang@gmail.com [richard.weiyang@gmail.com: remove duplicate call for set_page_links] Link: http://lkml.kernel.org/r/20170616092335.5177-2-richard.weiyang@gmail.com [akpm@linux-foundation.org: remove unused local `i'] Link: http://lkml.kernel.org/r/20170515085827.16474-12-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Tested-by: Dan Williams <dan.j.williams@intel.com> Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # For s390 bits Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daniel Kiper <daniel.kiper@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Tobias Regnery <tobias.regnery@gmail.com> Cc: Toshi Kani <toshi.kani@hpe.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
-rw-r--r--mm/memory_hotplug.c201
1 files changed, 122 insertions, 79 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b2ebe9ad7f6c..9438ffe24cb2 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -433,25 +433,6 @@ out_fail:
return -1;
}
-static struct zone * __meminit move_pfn_range(int zone_shift,
- unsigned long start_pfn, unsigned long end_pfn)
-{
- struct zone *zone = page_zone(pfn_to_page(start_pfn));
- int ret = 0;
-
- if (zone_shift < 0)
- ret = move_pfn_range_left(zone + zone_shift, zone,
- start_pfn, end_pfn);
- else if (zone_shift)
- ret = move_pfn_range_right(zone, zone + zone_shift,
- start_pfn, end_pfn);
-
- if (ret)
- return NULL;
-
- return zone + zone_shift;
-}
-
static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
unsigned long end_pfn)
{
@@ -493,23 +474,35 @@ static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
return 0;
}
-static int __meminit __add_section(int nid, struct zone *zone,
- unsigned long phys_start_pfn, bool want_memblock)
+static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
+ bool want_memblock)
{
int ret;
+ int i;
if (pfn_valid(phys_start_pfn))
return -EEXIST;
- ret = sparse_add_one_section(zone, phys_start_pfn);
-
+ ret = sparse_add_one_section(NODE_DATA(nid), phys_start_pfn);
if (ret < 0)
return ret;
- ret = __add_zone(zone, phys_start_pfn);
+ /*
+ * Make all the pages reserved so that nobody will stumble over half
+ * initialized state.
+ * FIXME: We also have to associate it with a node because pfn_to_node
+ * relies on having page with the proper node.
+ */
+ for (i = 0; i < PAGES_PER_SECTION; i++) {
+ unsigned long pfn = phys_start_pfn + i;
+ struct page *page;
+ if (!pfn_valid(pfn))
+ continue;
- if (ret < 0)
- return ret;
+ page = pfn_to_page(pfn);
+ set_page_node(page, nid);
+ SetPageReserved(page);
+ }
if (!want_memblock)
return 0;
@@ -523,7 +516,7 @@ static int __meminit __add_section(int nid, struct zone *zone,
* call this function after deciding the zone to which to
* add the new pages.
*/
-int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
+int __ref __add_pages(int nid, unsigned long phys_start_pfn,
unsigned long nr_pages, bool want_memblock)
{
unsigned long i;
@@ -531,8 +524,6 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
int start_sec, end_sec;
struct vmem_altmap *altmap;
- clear_zone_contiguous(zone);
-
/* during initialize mem_map, align hot-added range to section */
start_sec = pfn_to_section_nr(phys_start_pfn);
end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
@@ -552,7 +543,7 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
}
for (i = start_sec; i <= end_sec; i++) {
- err = __add_section(nid, zone, section_nr_to_pfn(i), want_memblock);
+ err = __add_section(nid, section_nr_to_pfn(i), want_memblock);
/*
* EEXIST is finally dealt with by ioresource collision
@@ -565,7 +556,6 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
}
vmemmap_populate_print_last();
out:
- set_zone_contiguous(zone);
return err;
}
EXPORT_SYMBOL_GPL(__add_pages);
@@ -1034,39 +1024,109 @@ static void node_states_set_node(int node, struct memory_notify *arg)
node_set_state(node, N_MEMORY);
}
-bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,
- enum zone_type target, int *zone_shift)
+bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_pages, int online_type)
{
- struct zone *zone = page_zone(pfn_to_page(pfn));
- enum zone_type idx = zone_idx(zone);
- int i;
+ struct pglist_data *pgdat = NODE_DATA(nid);
+ struct zone *movable_zone = &pgdat->node_zones[ZONE_MOVABLE];
+ struct zone *normal_zone = &pgdat->node_zones[ZONE_NORMAL];
- *zone_shift = 0;
+ /*
+ * TODO there shouldn't be any inherent reason to have ZONE_NORMAL
+ * physically before ZONE_MOVABLE. All we need is they do not
+ * overlap. Historically we didn't allow ZONE_NORMAL after ZONE_MOVABLE
+ * though so let's stick with it for simplicity for now.
+ * TODO make sure we do not overlap with ZONE_DEVICE
+ */
+ if (online_type == MMOP_ONLINE_KERNEL) {
+ if (zone_is_empty(movable_zone))
+ return true;
+ return movable_zone->zone_start_pfn >= pfn + nr_pages;
+ } else if (online_type == MMOP_ONLINE_MOVABLE) {
+ return zone_end_pfn(normal_zone) <= pfn;
+ }
- if (idx < target) {
- /* pages must be at end of current zone */
- if (pfn + nr_pages != zone_end_pfn(zone))
- return false;
+ /* MMOP_ONLINE_KEEP will always succeed and inherits the current zone */
+ return online_type == MMOP_ONLINE_KEEP;
+}
- /* no zones in use between current zone and target */
- for (i = idx + 1; i < target; i++)
- if (zone_is_initialized(zone - idx + i))
- return false;
- }
+static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long old_end_pfn = zone_end_pfn(zone);
- if (target < idx) {
- /* pages must be at beginning of current zone */
- if (pfn != zone->zone_start_pfn)
- return false;
+ if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
+ zone->zone_start_pfn = start_pfn;
+
+ zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
+}
+
+static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
- /* no zones in use between current zone and target */
- for (i = target + 1; i < idx; i++)
- if (zone_is_initialized(zone - idx + i))
- return false;
+ if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
+ pgdat->node_start_pfn = start_pfn;
+
+ pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
+}
+
+void move_pfn_range_to_zone(struct zone *zone,
+ unsigned long start_pfn, unsigned long nr_pages)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ int nid = pgdat->node_id;
+ unsigned long flags;
+
+ if (zone_is_empty(zone))
+ init_currently_empty_zone(zone, start_pfn, nr_pages);
+
+ clear_zone_contiguous(zone);
+
+ /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
+ pgdat_resize_lock(pgdat, &flags);
+ zone_span_writelock(zone);
+ resize_zone_range(zone, start_pfn, nr_pages);
+ zone_span_writeunlock(zone);
+ resize_pgdat_range(pgdat, start_pfn, nr_pages);
+ pgdat_resize_unlock(pgdat, &flags);
+
+ /*
+ * TODO now we have a visible range of pages which are not associated
+ * with their zone properly. Not nice but set_pfnblock_flags_mask
+ * expects the zone spans the pfn range. All the pages in the range
+ * are reserved so nobody should be touching them so we should be safe
+ */
+ memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn, MEMMAP_HOTPLUG);
+
+ set_zone_contiguous(zone);
+}
+
+/*
+ * Associates the given pfn range with the given node and the zone appropriate
+ * for the given online type.
+ */
+static struct zone * __meminit move_pfn_range(int online_type, int nid,
+ unsigned long start_pfn, unsigned long nr_pages)
+{
+ struct pglist_data *pgdat = NODE_DATA(nid);
+ struct zone *zone = &pgdat->node_zones[ZONE_NORMAL];
+
+ if (online_type == MMOP_ONLINE_KEEP) {
+ struct zone *movable_zone = &pgdat->node_zones[ZONE_MOVABLE];
+ /*
+ * MMOP_ONLINE_KEEP inherits the current zone which is
+ * ZONE_NORMAL by default but we might be within ZONE_MOVABLE
+ * already.
+ */
+ if (zone_intersects(movable_zone, start_pfn, nr_pages))
+ zone = movable_zone;
+ } else if (online_type == MMOP_ONLINE_MOVABLE) {
+ zone = &pgdat->node_zones[ZONE_MOVABLE];
}
- *zone_shift = target - idx;
- return true;
+ move_pfn_range_to_zone(zone, start_pfn, nr_pages);
+ return zone;
}
/* Must be protected by mem_hotplug_begin() */
@@ -1079,38 +1139,21 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
int nid;
int ret;
struct memory_notify arg;
- int zone_shift = 0;
- /*
- * This doesn't need a lock to do pfn_to_page().
- * The section can't be removed here because of the
- * memory_block->state_mutex.
- */
- zone = page_zone(pfn_to_page(pfn));
-
- if ((zone_idx(zone) > ZONE_NORMAL ||
- online_type == MMOP_ONLINE_MOVABLE) &&
- !can_online_high_movable(pfn_to_nid(pfn)))
+ nid = pfn_to_nid(pfn);
+ if (!allow_online_pfn_range(nid, pfn, nr_pages, online_type))
return -EINVAL;
- if (online_type == MMOP_ONLINE_KERNEL) {
- if (!zone_can_shift(pfn, nr_pages, ZONE_NORMAL, &zone_shift))
- return -EINVAL;
- } else if (online_type == MMOP_ONLINE_MOVABLE) {
- if (!zone_can_shift(pfn, nr_pages, ZONE_MOVABLE, &zone_shift))
- return -EINVAL;
- }
-
- zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
- if (!zone)
+ if (online_type == MMOP_ONLINE_MOVABLE && !can_online_high_movable(nid))
return -EINVAL;
+ /* associate pfn range with the zone */
+ zone = move_pfn_range(online_type, nid, pfn, nr_pages);
+
arg.start_pfn = pfn;
arg.nr_pages = nr_pages;
node_states_check_changes_online(nr_pages, zone, &arg);
- nid = zone_to_nid(zone);
-
ret = memory_notify(MEM_GOING_ONLINE, &arg);
ret = notifier_to_errno(ret);
if (ret)