On 01/14/14 at 02:21pm, Prarit Bhargava 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 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. > > [v2]: changed acpi_no_memhotplug to bool > [v3]: cleaned up Documentation/kernel-parameters.txt > > Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> > Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> > Cc: Len Brown <lenb@xxxxxxxxxx> > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> > Cc: kosaki.motohiro@xxxxxxxxx > Cc: dyoung@xxxxxxxxxx > Cc: toshi.kani@xxxxxx > Cc: isimatu.yasuaki@xxxxxxxxxxxxxx > Cc: kosaki.motohiro@xxxxxxxxx > Cc: linux-acpi@xxxxxxxxxxxxxxx > Cc: kexec@xxxxxxxxxxxxxxxxxxx > --- > Documentation/kernel-parameters.txt | 3 +++ > drivers/acpi/acpi_memhotplug.c | 12 ++++++++++++ > 2 files changed, 15 insertions(+) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index b9e9bd8..ea93f75 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -343,6 +343,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > no: ACPI OperationRegions are not marked as reserved, > no further checks are performed. > > + acpi_no_memhotplug [ACPI] Disable memory hotplug. Useful for kexec > + and kdump kernels. > + > add_efi_memmap [EFI; X86] Include EFI memory map in > kernel's map of available physical RAM. > > diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c > index 551dad7..4a0fa94 100644 > --- a/drivers/acpi/acpi_memhotplug.c > +++ b/drivers/acpi/acpi_memhotplug.c > @@ -361,7 +361,19 @@ static void acpi_memory_device_remove(struct acpi_device *device) > acpi_memory_device_free(mem_device); > } > > +static bool acpi_no_memhotplug; > + > void __init acpi_memory_hotplug_init(void) > { > + if (acpi_no_memhotplug) > + return; > + > acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory"); > } > + > +static int __init disable_acpi_memory_hotplug(char *str) > +{ > + acpi_no_memhotplug = true; > + return 1; > +} > +__setup("acpi_no_memhotplug", disable_acpi_memory_hotplug); > -- > 1.7.9.3 > Acked-by: Dave Young <dyoung@xxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html