On 10/12/2015 08:58 AM, Changsheng Liu wrote: > From: Changsheng Liu <[email protected]> > > After the user config CONFIG_MOVABLE_NODE, > When the memory is hot added, should_add_memory_movable() return 0 > because all zones including ZONE_MOVABLE are empty, > so the memory that was hot added will be assigned to ZONE_NORMAL > and ZONE_NORMAL will be created firstly. > But we want the whole node to be added to ZONE_MOVABLE by default. > > So we change should_add_memory_movable(): if the user config > CONFIG_MOVABLE_NODE and sysctl parameter hotadd_memory_as_movable is 1 > and the ZONE_NORMAL is empty or the pfn of the hot-added memory > is after the end of the ZONE_NORMAL it will always return 1 > and then the whole node will be added to ZONE_MOVABLE by default. > If we want the node to be assigned to ZONE_NORMAL, > we can do it as follows: > "echo online_kernel > /sys/devices/system/memory/memoryXXX/state" > > By the patch, the behavious of kernel is changed by sysctl, > user can automatically create movable memory > by only the following udev rule: > SUBSYSTEM=="memory", ACTION=="add", > ATTR{state}=="offline", ATTR{state}="online"
So just to be clear, we are adding a new sysctl, because the existing movable_node kernel option, which is checked by movable_node_is_enabled(), and does the same thing for non-hot-added-memory (?) cannot be reused for hot-added memory, as that would be a potentially surprising behavior change? Correct? Then this should be mentioned in the changelog too, and wherever "movable_node" is documented should also mention the new sysctl. Personally, I would expect movable_node to affect hot-added memory as well, and would be surprised that it doesn't... > Signed-off-by: Changsheng Liu <[email protected]> > Signed-off-by: Xiaofeng Yan <[email protected]> > Tested-by: Dongdong Fan <[email protected]> > Cc: Wang Nan <[email protected]> > Cc: Dave Hansen <[email protected]> > Cc: Yinghai Lu <[email protected]> > Cc: Tang Chen <[email protected]> > Cc: Yasuaki Ishimatsu <[email protected]> > Cc: Toshi Kani <[email protected]> > Cc: Xishi Qiu <[email protected]> > --- > Documentation/memory-hotplug.txt | 5 ++++- > kernel/sysctl.c | 15 +++++++++++++++ > mm/memory_hotplug.c | 24 ++++++++++++++++++++++++ > 3 files changed, 43 insertions(+), 1 deletions(-) > > diff --git a/Documentation/memory-hotplug.txt > b/Documentation/memory-hotplug.txt > index ce2cfcf..7ac7485 100644 > --- a/Documentation/memory-hotplug.txt > +++ b/Documentation/memory-hotplug.txt > @@ -277,7 +277,7 @@ And if the memory block is in ZONE_MOVABLE, you can > change it to ZONE_NORMAL: > After this, memory block XXX's state will be 'online' and the amount of > available memory will be increased. > > -Currently, newly added memory is added as ZONE_NORMAL (for powerpc, > ZONE_DMA). > +Currently, newly added memory is added as ZONE_NORMAL or ZONE_MOVABLE (for > powerpc, ZONE_DMA). > This may be changed in future. > > > @@ -319,6 +319,9 @@ creates ZONE_MOVABLE as following. > Size of memory not for movable pages (not for offline) is TOTAL - ZZZZ. > Size of memory for movable pages (for offline) is ZZZZ. > > +And a sysctl parameter for assigning the hot added memory to ZONE_MOVABLE is > +supported. If the value of "kernel/hotadd_memory_as_movable" is 1,the hot > added > +memory will be assigned to ZONE_MOVABLE by default. > > Note: Unfortunately, there is no information to show which memory block > belongs > to ZONE_MOVABLE. This is TBD. > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index 19b62b5..16b1501 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -166,6 +166,10 @@ extern int unaligned_dump_stack; > extern int no_unaligned_warning; > #endif > > +#ifdef CONFIG_MOVABLE_NODE > +extern int hotadd_memory_as_movable; > +#endif > + > #ifdef CONFIG_PROC_SYSCTL > > #define SYSCTL_WRITES_LEGACY -1 > @@ -1139,6 +1143,17 @@ static struct ctl_table kern_table[] = { > .proc_handler = timer_migration_handler, > }, > #endif > +/*If the value of "kernel/hotadd_memory_as_movable" is 1,the hot added > + * memory will be assigned to ZONE_MOVABLE by default.*/ > +#ifdef CONFIG_MOVABLE_NODE > + { > + .procname = "hotadd_memory_as_movable", > + .data = &hotadd_memory_as_movable, > + .maxlen = sizeof(int), > + .mode = 0644, > + .proc_handler = proc_dointvec, > + }, > +#endif > { } > }; > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 26fbba7..eca5512 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -37,6 +37,11 @@ > > #include "internal.h" > > +/*If the global variable value is 1, > + * the hot added memory will be assigned to ZONE_MOVABLE by default > + */ > +int hotadd_memory_as_movable; > + > /* > * online_page_callback contains pointer to current page onlining function. > * Initially it is generic_online_page(). If it is required it could be > @@ -1190,6 +1195,9 @@ 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 config CONFIG_MOVABLE_NODE and set the sysctl parameter > + * "hotadd_memory_as_movable" and added memory does not overlap the zone > + * before MOVABLE_ZONE,the memory will be 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) > @@ -1197,6 +1205,22 @@ 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 *pre_zone = pgdat->node_zones + (ZONE_MOVABLE - 1); > + /* > + * The system configs CONFIG_MOVABLE_NODE to assign a node > + * which has only movable memory,so the hot-added memory should > + * be assigned to ZONE_MOVABLE by default, > + * but the function zone_for_memory() assign the hot-added memory > + * to ZONE_NORMAL(x86_64) by default.Kernel does not allow to > + * create ZONE_MOVABLE before ZONE_NORMAL,So if the value of > + * sysctl parameter "hotadd_memory_as_movable" is 1 > + * and the ZONE_NORMAL is empty or the pfn of the hot-added memory > + * is after the end of ZONE_NORMAL > + * the hot-added memory will be assigned to ZONE_MOVABLE. > + */ > + if (hotadd_memory_as_movable > + && (zone_is_empty(pre_zone) || zone_end_pfn(pre_zone) <= start_pfn)) > + return 1; > > if (zone_is_empty(movable_zone)) > return 0; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
