Post the regression fix in a standalone patch as Andrew suggested for -stable branch better back porting. This is rebased on the latest master branch of mainline kenrel, surely there's almost no change comparing with v2. https://lore.kernel.org/linux-mm/20201220082754.6900-1-bhe@xxxxxxxxxx/ Tested on a system with 24G ram as below, adding 'memmap=128M!0x500000000' to split the one ram region into two regions in numa node1 to simulate the scenario of VMware. [ +0.000000] BIOS-provided physical RAM map: [ +0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009bfff] usable [ +0.000000] BIOS-e820: [mem 0x000000000009c000-0x000000000009ffff] reserved [ +0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved [ +0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000006cdcefff] usable [ +0.000000] BIOS-e820: [mem 0x000000006cdcf000-0x000000006efcefff] reserved [ +0.000000] BIOS-e820: [mem 0x000000006efcf000-0x000000006fdfefff] ACPI NVS [ +0.000000] BIOS-e820: [mem 0x000000006fdff000-0x000000006fffefff] ACPI data [ +0.000000] BIOS-e820: [mem 0x000000006ffff000-0x000000006fffffff] usable [ +0.000000] BIOS-e820: [mem 0x0000000070000000-0x000000008fffffff] reserved [ +0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000ffffffff] reserved [ +0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000067f1fffff] usable [ +0.000000] BIOS-e820: [mem 0x000000067f200000-0x000000067fffffff] reserved Test passed as below. As you can see, with patch applied, memmap init will cost much less time on numa node 1: Without the patch: [ 0.065029] Early memory node ranges [ 0.065030] node 0: [mem 0x0000000000001000-0x000000000009bfff] [ 0.065032] node 0: [mem 0x0000000000100000-0x000000006cdcefff] [ 0.065034] node 0: [mem 0x000000006ffff000-0x000000006fffffff] [ 0.065036] node 0: [mem 0x0000000100000000-0x000000027fffffff] [ 0.065038] node 1: [mem 0x0000000280000000-0x00000004ffffffff] [ 0.065040] node 1: [mem 0x0000000508000000-0x000000067f1fffff] [ 0.065185] Zeroed struct page in unavailable ranges: 16533 pages [ 0.065187] Initmem setup node 0 [mem 0x0000000000001000-0x000000027fffffff] [ 0.069616] Initmem setup node 1 [mem 0x0000000280000000-0x000000067f1fffff] [ 0.096298] ACPI: PM-Timer IO Port: 0x408 With the patch applied: [ 0.065029] Early memory node ranges [ 0.065030] node 0: [mem 0x0000000000001000-0x000000000009bfff] [ 0.065032] node 0: [mem 0x0000000000100000-0x000000006cdcefff] [ 0.065034] node 0: [mem 0x000000006ffff000-0x000000006fffffff] [ 0.065036] node 0: [mem 0x0000000100000000-0x000000027fffffff] [ 0.065038] node 1: [mem 0x0000000280000000-0x00000004ffffffff] [ 0.065041] node 1: [mem 0x0000000508000000-0x000000067f1fffff] [ 0.065187] Zeroed struct page in unavailable ranges: 16533 pages [ 0.065189] Initmem setup node 0 [mem 0x0000000000001000-0x000000027fffffff] [ 0.069572] Initmem setup node 1 [mem 0x0000000280000000-0x000000067f1fffff] [ 0.070161] ACPI: PM-Timer IO Port: 0x408 Baoquan He (1): mm: memmap defer init dosn't work as expected arch/ia64/mm/init.c | 4 ++-- include/linux/mm.h | 5 +++-- mm/memory_hotplug.c | 2 +- mm/page_alloc.c | 8 +++++--- 4 files changed, 11 insertions(+), 8 deletions(-) -- 2.17.2
