From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 589F96B0038 for ; Mon, 6 Nov 2017 12:35:21 -0500 (EST) Received: by mail-wr0-f198.google.com with SMTP id g10so6425506wrg.6 for ; Mon, 06 Nov 2017 09:35:21 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id d93si6511026edc.450.2017.11.06.09.35.19 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 06 Nov 2017 09:35:19 -0800 (PST) Date: Mon, 6 Nov 2017 12:35:11 -0500 From: Johannes Weiner Subject: Re: [PATCH] mm, sparse: do not swamp log with huge vmemmap allocation failures Message-ID: <20171106173511.GA32336@cmpxchg.org> References: <20171106092228.31098-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171106092228.31098-1-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andrew Morton , Vlastimil Babka , linux-mm@kvack.org, LKML , Michal Hocko On Mon, Nov 06, 2017 at 10:22:28AM +0100, Michal Hocko wrote: > From: Michal Hocko > > 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] [] dump_trace+0x59/0x310 > [146792.281436] [] show_stack_log_lvl+0xea/0x170 > [146792.281440] [] show_stack+0x21/0x40 > [146792.281448] [] dump_stack+0x5c/0x7c > [146792.281464] [] warn_alloc_failed+0xe2/0x150 > [146792.281471] [] __alloc_pages_nodemask+0x3ed/0xb20 > [146792.281489] [] alloc_pages_current+0x7f/0x100 > [146792.281503] [] vmemmap_alloc_block+0x79/0xb6 > [146792.281510] [] __vmemmap_alloc_block_buf+0x136/0x145 > [146792.281524] [] vmemmap_populate+0xd2/0x2b9 > [146792.281529] [] sparse_mem_map_populate+0x23/0x30 > [146792.281532] [] sparse_add_one_section+0x68/0x18e > [146792.281537] [] __add_pages+0x10a/0x1d0 > [146792.281553] [] arch_add_memory+0x4a/0xc0 > [146792.281559] [] add_memory_resource+0x89/0x160 > [146792.281564] [] add_memory+0x6d/0xd0 > [146792.281585] [] acpi_memory_device_add+0x181/0x251 > [146792.281597] [] acpi_bus_attach+0xfd/0x19b > [146792.281602] [] acpi_bus_scan+0x59/0x69 > [146792.281604] [] acpi_device_hotplug+0xd2/0x41f > [146792.281608] [] acpi_hotplug_work_fn+0x1a/0x23 > [146792.281623] [] process_one_work+0x14e/0x410 > [146792.281630] [] worker_thread+0x116/0x490 > [146792.281637] [] kthread+0xbd/0xe0 > [146792.281651] [] 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 > Signed-off-by: Michal Hocko > --- > 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@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org