On Mon, Nov 06, 2017 at 10:22:28AM +0100, Michal Hocko wrote: > From: Michal Hocko <mhocko@xxxxxxxx> > > While doing a memory hotplug tests under a heavy memory pressure we have > noticed too many page allocation failures when allocating vmemmap memmap > backed by huge page > [146792.281354] kworker/u3072:1: page allocation failure: order:9, mode:0x24084c0(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO) > [...] > [146792.281394] Call Trace: > [146792.281430] [<ffffffff81019a99>] dump_trace+0x59/0x310 > [146792.281436] [<ffffffff81019e3a>] show_stack_log_lvl+0xea/0x170 > [146792.281440] [<ffffffff8101abc1>] show_stack+0x21/0x40 > [146792.281448] [<ffffffff8130f040>] dump_stack+0x5c/0x7c > [146792.281464] [<ffffffff8118c982>] warn_alloc_failed+0xe2/0x150 > [146792.281471] [<ffffffff8118cddd>] __alloc_pages_nodemask+0x3ed/0xb20 > [146792.281489] [<ffffffff811d3aaf>] alloc_pages_current+0x7f/0x100 > [146792.281503] [<ffffffff815dfa2c>] vmemmap_alloc_block+0x79/0xb6 > [146792.281510] [<ffffffff815dfbd3>] __vmemmap_alloc_block_buf+0x136/0x145 > [146792.281524] [<ffffffff815dd0c5>] vmemmap_populate+0xd2/0x2b9 > [146792.281529] [<ffffffff815dffd9>] sparse_mem_map_populate+0x23/0x30 > [146792.281532] [<ffffffff815df88d>] sparse_add_one_section+0x68/0x18e > [146792.281537] [<ffffffff815d9f5a>] __add_pages+0x10a/0x1d0 > [146792.281553] [<ffffffff8106249a>] arch_add_memory+0x4a/0xc0 > [146792.281559] [<ffffffff815da1f9>] add_memory_resource+0x89/0x160 > [146792.281564] [<ffffffff815da33d>] add_memory+0x6d/0xd0 > [146792.281585] [<ffffffff813d36c4>] acpi_memory_device_add+0x181/0x251 > [146792.281597] [<ffffffff813946e5>] acpi_bus_attach+0xfd/0x19b > [146792.281602] [<ffffffff81394866>] acpi_bus_scan+0x59/0x69 > [146792.281604] [<ffffffff813949de>] acpi_device_hotplug+0xd2/0x41f > [146792.281608] [<ffffffff8138db67>] acpi_hotplug_work_fn+0x1a/0x23 > [146792.281623] [<ffffffff81093cee>] process_one_work+0x14e/0x410 > [146792.281630] [<ffffffff81094546>] worker_thread+0x116/0x490 > [146792.281637] [<ffffffff810999ed>] kthread+0xbd/0xe0 > [146792.281651] [<ffffffff815e4e7f>] ret_from_fork+0x3f/0x70 > > and we do see many of those because essentially every the allocation > failes for each memory section. This is overly excessive way to tell > user that there is nothing to really worry about because we do have > a fallback mechanism to use base pages. The only downside might be a > performance degradation due to TLB pressure. > > This patch changes vmemmap_alloc_block to use __GFP_NOWARN and warn > explicitly once on the first allocation failure. This will reduce the > noise in the kernel log considerably, while we still have an indication > that a performance might be impacted. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> > --- > Hi, > this has somehow fell of my radar completely. The patch is essentially > what Johannes suggested [1] so I have added his s-o-b and added the > changelog into it. Looks good to me. -- 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>
