On Sunday 13 October 2013 03:51 PM, Tejun Heo wrote: > On Sat, Oct 12, 2013 at 05:58:51PM -0400, Santosh Shilimkar wrote: >> From: Grygorii Strashko <grygorii.strashko@xxxxxx> >> >> Now the Nobootmem allocator will always try to free memory allocated for >> reserved memory regions (free_low_memory_core_early()) without taking >> into to account current memblock debugging configuration >> (CONFIG_ARCH_DISCARD_MEMBLOCK and CONFIG_DEBUG_FS state). >> As result if: >> - CONFIG_DEBUG_FS defined >> - CONFIG_ARCH_DISCARD_MEMBLOCK not defined; >> - reserved memory regions array have been resized during boot >> >> then: >> - memory allocated for reserved memory regions array will be freed to >> buddy allocator; >> - debug_fs entry "sys/kernel/debug/memblock/reserved" will show garbage >> instead of state of memory reservations. like: >> 0: 0x98393bc0..0x9a393bbf >> 1: 0xff120000..0xff11ffff >> 2: 0x00000000..0xffffffff >> >> Hence, do not free memory allocated for reserved memory regions if >> defined(CONFIG_DEBUG_FS) && !defined(CONFIG_ARCH_DISCARD_MEMBLOCK). >> >> Cc: Yinghai Lu <yinghai@xxxxxxxxxx> >> Cc: Tejun Heo <tj@xxxxxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> >> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> >> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> >> --- >> mm/memblock.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/mm/memblock.c b/mm/memblock.c >> index d903138..1bb2cc0 100644 >> --- a/mm/memblock.c >> +++ b/mm/memblock.c >> @@ -169,6 +169,10 @@ phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info( >> if (memblock.reserved.regions == memblock_reserved_init_regions) >> return 0; >> > > Please add comment explaining why the following test exists. It's > pretty difficult to deduce the reason only from the code. > ok. >> + if (IS_ENABLED(CONFIG_DEBUG_FS) && >> + !IS_ENABLED(CONFIG_ARCH_DISCARD_MEMBLOCK)) >> + return 0; >> + > > Also, as this is another fix patch, can you please move this to the > head of the series? > Sure -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>