Hi, baohua Thank you for your attention.
In my understanding of the MEMORY_HOTPLUG this patch has no effect on it. The reason is that in sparse_add_one_section() the memory that memmap needs from Slab if kernel start completed，this memory has nothing to do with memblock alloc/ free memory in the process of kernel start. You may have a look vmemmap_alloc_block () this function. If I don't understand right welcome pointed out in a timely manner. Thanks! -----邮件原件----- 发件人: Song Bao Hua (Barry Song) 发送时间: 2020年7月8日 15:19 收件人: liwei (CM) <liwei...@huawei.com>; catalin.mari...@arm.com; w...@kernel.org 抄送: fengbaopeng <fengbaope...@hisilicon.com>; nsaenzjulie...@suse.de; steve.cap...@arm.com; r...@linux.ibm.com; linux-arm-ker...@lists.infradead.org; linux-kernel@vger.kernel.org; sujunfei <sujunf...@hisilicon.com> 主题: RE: [PATCH] arm64: mm: free unused memmap for sparse memory model that define VMEMMAP > -----Original Message----- > From: liwei (CM) > Sent: Wednesday, July 8, 2020 1:56 PM > To: catalin.mari...@arm.com; w...@kernel.org > Cc: liwei (CM) <liwei...@huawei.com>; fengbaopeng > <fengbaope...@hisilicon.com>; nsaenzjulie...@suse.de; > steve.cap...@arm.com; r...@linux.ibm.com; Song Bao Hua (Barry Song) > <song.bao....@hisilicon.com>; linux-arm-ker...@lists.infradead.org; > linux-kernel@vger.kernel.org; sujunfei <sujunf...@hisilicon.com> > Subject: [PATCH] arm64: mm: free unused memmap for sparse memory model > that define VMEMMAP > > For the memory hole, sparse memory model that define SPARSEMEM_VMEMMAP > do not free the reserved memory for the page map, this patch do it. Hello Wei, Just curious if this patch breaks MEMORY_HOTPLUG? > > Signed-off-by: Wei Li <liwei...@huawei.com> > Signed-off-by: Chen Feng <puck.c...@hisilicon.com> > Signed-off-by: Xia Qing <saberlily....@hisilicon.com> > --- > arch/arm64/mm/init.c | 81 > +++++++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 71 insertions(+), 10 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index > 1e93cfc7c47a..d1b56b47d5ba 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -441,7 +441,48 @@ void __init bootmem_init(void) > memblock_dump_all(); > } > Thanks Barry
