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Date: Fri, 11 Sep 2015 12:42:16 -0700 (PDT)
From: Yasuaki Ishimatsu <yasu.isimatu@...il.com>
To: Changsheng Liu <liuchangsheng@...pur.com>
Cc: <akpm@...ux-foundation.org>, <isimatu.yasuaki@...fujitsu.com>,
<vbabka@...e.cz>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>, <wunan@...pur.com>,
<yanxiaofeng@...pur.com>, <fandd@...pur.com>,
Changsheng Liu <liuchangcheng@...pur.com>
Subject: Re: [PATCH V4] mm: memory hot-add: memory can not be added to
movable zone defaultly
Hi Changsheng,
Thank you for your comments.
I'm on vacation. So After that, I'll repost the patch.
Thanks,
Yasuaki Ishimatsu
On Sun, 6 Sep 2015 16:33:42 +0800
Changsheng Liu <liuchangsheng@...pur.com> wrote:
>
>
> On 9/1/2015 23:37, Yasuaki Ishimatsu wrote:
> > On Mon, 31 Aug 2015 01:58:40 -0400
> > Changsheng Liu <liuchangsheng@...pur.com> wrote:
> >
> >> From: Changsheng Liu <liuchangcheng@...pur.com>
> >>
> >> After the user config CONFIG_MOVABLE_NODE and movable_node kernel option,
> >> When the memory is hot added, should_add_memory_movable() return 0
> >> because all zones including movable zone are empty,
> >> so the memory that was hot added will be added to the normal zone
> >> and the normal zone will be created firstly.
> >> But we want the whole node to be added to movable zone defaultly.
> >>
> >> So we change should_add_memory_movable(): if the user config
> >> CONFIG_MOVABLE_NODE and movable_node kernel option
> >> it will always return 1 and all zones is empty at the same time,
> >> so that the movable zone will be created firstly
> >> and then the whole node will be added to movable zone defaultly.
> >> If we want the node to be added to normal zone,
> >> we can do it as follows:
> >> "echo online_kernel > /sys/devices/system/memory/memoryXXX/state"
> >>
> >> If the memory is added to movable zone defaultly,
> >> the user can offline it and add it to other zone again.
> >> But if the memory is added to normal zone defaultly,
> >> the user will not offline the memory used by kernel.
> >>
> >> Reviewed-by: Andrew Morton <akpm@...ux-foundation.org>
> >> Reviewed-by: Yasuaki Ishimatsu <yasu.isimatu@...il.com>
> >> Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
> >> Reviewed-by: Xiaofeng Yan <yanxiaofeng@...pur.com>
> >> Signed-off-by: Changsheng Liu <liuchangcheng@...pur.com>
> >> Tested-by: Dongdong Fan <fandd@...pur.com>
> >> ---
> >> mm/memory_hotplug.c | 5 +++++
> >> 1 files changed, 5 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> >> index 26fbba7..d1149ff 100644
> >> --- a/mm/memory_hotplug.c
> >> +++ b/mm/memory_hotplug.c
> >> @@ -1197,6 +1197,11 @@ static int should_add_memory_movable(int nid, u64 start, u64 size)
> >> unsigned long start_pfn = start >> PAGE_SHIFT;
> >> pg_data_t *pgdat = NODE_DATA(nid);
> >> struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
> >> + struct zone *normal_zone = pgdat->node_zones + ZONE_NORMAL;
> >> +
> >> + if (movable_node_is_enabled()
> >> + && (zone_end_pfn(normal_zone) <= start_pfn))
> >> + return 1;
> > If system boots up without movable_node, kernel behavior is changed by the patch.
> > And you syould consider other zone.
> >
> > How about it. The patch is no build and test.
> >
> >
> > ---
> > mm/memory_hotplug.c | 36 ++++++++++++++++++++++++++++++++----
> > 1 files changed, 32 insertions(+), 4 deletions(-)
> >
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index 6da82bc..321595d 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -1198,6 +1198,8 @@ static int check_hotplug_memory_range(u64 start, u64 size)
> > /*
> > * If movable zone has already been setup, newly added memory should be check.
> > * If its address is higher than movable zone, it should be added as movable.
> > + * And if system boots up with movable_zone and added memory does not overlap
> > + * other zone except for movable zone, the memory is added as movable.
> > * Without this check, movable zone may overlap with other zone.
> > */
> > static int should_add_memory_movable(int nid, u64 start, u64 size)
> > @@ -1205,14 +1207,40 @@ static int should_add_memory_movable(int nid, u64 start, u64 size)
> > unsigned long start_pfn = start >> PAGE_SHIFT;
> > pg_data_t *pgdat = NODE_DATA(nid);
> > struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
> > + struct zone *zone;
> > + enum zone_type zt = ZONE_MOVABLE - 1;
> > +
> > + /*
> > + * If memory is added after ZONE_MOVALBE, the memory is managed as
> > + * movable.
> > + */
> > + if (!zone_is_empty(movable_zone) &&
> > + (movable_zone->zone_start_pfn <= start_pfn))
> > + return 1;
> >
> > - if (zone_is_empty(movable_zone))
> > + if (!movable_node_is_enabled())
> > return 0;
> >
> > - if (movable_zone->zone_start_pfn <= start_pfn)
> > - return 1;
> > + /*
> > + * Find enabled zone and check the added memory.
> > + * If the memory is added after the enabled zone, the memory is
> > + * managed as movable.
> > + *
> > + * If all zones are empty, the memory is also managed as movable.
> > + */
> > + for (; zt >= ZONE_DMA; zt--) {
> > + zone = pgdat->node_zones + zt;
> >
> > - return 0;
> > + if (zone_is_empty(zone))
> > + continue;
> > +
> > + if (zone_end_pfn(zone) <= start_pfn)
> > + return 1;
> > + else
> > + return 0;
> > + }
> > +
> > + return 1;
> > }
> >
> The function zone_for_memory() adds the memory to
> ZONE_NORMAL(x86_64)/ZONE_HIGH(x86_32) defaultly, So I think the system
> just need check the added-memory is whether after the ZONE_NORMAL/ZONE_HIGH
> > int zone_for_memory(int nid, u64 start, u64 size, int zone_default)
>
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