On 01/13/2014 05:17 PM, KOSAKI Motohiro wrote: > On Mon, Jan 13, 2014 at 4:56 PM, Prarit Bhargava <prarit@xxxxxxxxxx> wrote: >> When booting a kexec/kdump kernel on a system that has specific memory hotplug >> regions the boot will fail with warnings like: >> >> [ 2.939467] swapper/0: page allocation failure: order:9, mode:0x84d0 >> [ 2.946564] CPU: 0 PID: 1 Comm: swapper/0 Not tainted >> 3.10.0-65.el7.x86_64 #1 >> [ 2.954532] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS >> QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011 >> [ 2.964926] 0000000000000000 ffff8800341bd8c8 ffffffff815bcc67 >> ffff8800341bd950 >> [ 2.973224] ffffffff8113b1a0 ffff880036339b00 0000000000000009 >> 00000000000084d0 >> [ 2.981523] ffff8800341bd950 ffffffff815b87ee 0000000000000000 >> 0000000000000200 >> [ 2.989821] Call Trace: >> [ 2.992560] [<ffffffff815bcc67>] dump_stack+0x19/0x1b >> [ 2.998300] [<ffffffff8113b1a0>] warn_alloc_failed+0xf0/0x160 >> [ 3.004817] [<ffffffff815b87ee>] ? >> __alloc_pages_direct_compact+0xac/0x196 >> [ 3.012594] [<ffffffff8113f14f>] __alloc_pages_nodemask+0x7ff/0xa00 >> [ 3.019692] [<ffffffff815b417c>] vmemmap_alloc_block+0x62/0xba >> [ 3.026303] [<ffffffff815b41e9>] vmemmap_alloc_block_buf+0x15/0x3b >> [ 3.033302] [<ffffffff815b1ff6>] vmemmap_populate+0xb4/0x21b >> [ 3.039718] [<ffffffff815b461d>] sparse_mem_map_populate+0x27/0x35 >> [ 3.046717] [<ffffffff815b400f>] sparse_add_one_section+0x7a/0x185 >> [ 3.053720] [<ffffffff815a1e9f>] __add_pages+0xaf/0x240 >> [ 3.059656] [<ffffffff81047359>] arch_add_memory+0x59/0xd0 >> [ 3.065877] [<ffffffff815a21d9>] add_memory+0xb9/0x1b0 >> [ 3.071713] [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d >> [ 3.078813] [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd >> [ 3.085719] [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f >> [ 3.092716] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90 >> [ 3.100004] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90 >> [ 3.107293] [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5 >> [ 3.113904] [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d >> [ 3.119933] [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160 >> [ 3.126153] [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6 >> [ 3.131987] [<ffffffff81a1fd58>] ? acpi_sleep_proc_init+0x2a/0x2a >> [ 3.138889] [<ffffffff810020e2>] do_one_initcall+0xe2/0x190 >> [ 3.145210] [<ffffffff819e20c4>] kernel_init_freeable+0x17c/0x207 >> [ 3.152111] [<ffffffff819e18d0>] ? do_early_param+0x88/0x88 >> [ 3.158430] [<ffffffff8159fea0>] ? rest_init+0x80/0x80 >> [ 3.164264] [<ffffffff8159feae>] kernel_init+0xe/0x180 >> [ 3.170097] [<ffffffff815cca2c>] ret_from_fork+0x7c/0xb0 >> [ 3.176123] [<ffffffff8159fea0>] ? rest_init+0x80/0x80 >> [ 3.181956] Mem-Info: >> [ 3.184490] Node 0 DMA per-cpu: >> [ 3.188007] CPU 0: hi: 0, btch: 1 usd: 0 >> [ 3.193353] Node 0 DMA32 per-cpu: >> [ 3.197060] CPU 0: hi: 42, btch: 7 usd: 0 >> [ 3.202410] active_anon:0 inactive_anon:0 isolated_anon:0 >> [ 3.202410] active_file:0 inactive_file:0 isolated_file:0 >> [ 3.202410] unevictable:0 dirty:0 writeback:0 unstable:0 >> [ 3.202410] free:872 slab_reclaimable:13 slab_unreclaimable:1880 >> [ 3.202410] mapped:0 shmem:0 pagetables:0 bounce:0 >> [ 3.202410] free_cma:0 >> >> because the system has run out of memory at boot time. This occurs >> because of the following sequence in the boot: >> >> Main kernel boots and sets E820 map. The second kernel is booted with a >> map generated by the kdump service using memmap= and memmap=exactmap. >> These parameters are added to the kernel parameters of the kexec/kdump >> kernel. The kexec/kdump kernel has limited memory resources so as not >> to severely impact the main kernel. >> >> The system then panics and the kdump/kexec kernel boots (which is a >> completely new kernel boot). During this boot ACPI is initialized and the >> kernel (as can be seen above) traverses the ACPI namespace and finds an >> entry for a memory device to be hotadded. >> >> ie) >> >> [ 3.053720] [<ffffffff815a1e9f>] __add_pages+0xaf/0x240 >> [ 3.059656] [<ffffffff81047359>] arch_add_memory+0x59/0xd0 >> [ 3.065877] [<ffffffff815a21d9>] add_memory+0xb9/0x1b0 >> [ 3.071713] [<ffffffff81333b9c>] acpi_memory_device_add+0x18d/0x26d >> [ 3.078813] [<ffffffff81309a01>] acpi_bus_device_attach+0x7d/0xcd >> [ 3.085719] [<ffffffff8132379d>] acpi_ns_walk_namespace+0xc8/0x17f >> [ 3.092716] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90 >> [ 3.100004] [<ffffffff81309984>] ? acpi_bus_type_and_status+0x90/0x90 >> [ 3.107293] [<ffffffff81323c8c>] acpi_walk_namespace+0x95/0xc5 >> [ 3.113904] [<ffffffff8130a6d6>] acpi_bus_scan+0x8b/0x9d >> [ 3.119933] [<ffffffff81a2019a>] acpi_scan_init+0x63/0x160 >> [ 3.126153] [<ffffffff81a1ffb5>] acpi_init+0x25d/0x2a6 >> >> At this point the kernel adds page table information and the the kexec/kdump >> kernel runs out of memory. >> >> This can also be reproduced with a "regular" kernel by using the >> memmap=exactmap and mem=X parameters on the main kernel and booting. >> >> This patchset resolves the problem by adding a kernel parameter, >> acpi_no_memhotplug, to disable ACPI memory hotplug. ACPI memory hotplug >> should also be disabled by default when a user specified a memory mapping with >> "memmap=exactmap" or "mem=X". >> >> Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> >> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >> Cc: Ingo Molnar <mingo@xxxxxxxxxx> >> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> >> Cc: x86@xxxxxxxxxx >> Cc: Len Brown <lenb@xxxxxxxxxx> >> Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> >> Cc: Linn Crosetto <linn@xxxxxx> >> Cc: Pekka Enberg <penberg@xxxxxxxxxx> >> Cc: Yinghai Lu <yinghai@xxxxxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Cc: Toshi Kani <toshi.kani@xxxxxx> >> Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx> >> Cc: Wen Congyang <wency@xxxxxxxxxxxxxx> >> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> >> Cc: kosaki.motohiro@xxxxxxxxx >> Cc: dyoung@xxxxxxxxxx >> Cc: Toshi Kani <toshi.kani@xxxxxx> >> Cc: linux-acpi@xxxxxxxxxxxxxxx >> Cc: linux-mm@xxxxxxxxx > > I think we need a knob manually enable mem-hotplug when specify memmap. But > it is another story. > > Acked-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> As mentioned, self-NAK. I have seen a system that I needed to specify memmap=exactmap & had hotplug memory. I will only keep the acpi_no_memhotplug option in the next version of the patch. P. -- 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>