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Date: Sun, 6 Sep 2015 16:33:42 +0800 From: Changsheng Liu <liuchangsheng@...pur.com> To: Yasuaki Ishimatsu <yasu.isimatu@...il.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 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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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