From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Perches Subject: Re: [PATCH v2 net-next] net: ethtool: convert large order kmalloc allocations to vzalloc Date: Mon, 30 Jan 2017 19:28:01 -0800 Message-ID: <1485833281.20550.17.camel@perches.com> References: <1485829518-190263-1-git-send-email-ast@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , netdev@vger.kernel.org To: Alexei Starovoitov , "David S . Miller" Return-path: Received: from smtprelay0149.hostedemail.com ([216.40.44.149]:40165 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750730AbdAaD24 (ORCPT ); Mon, 30 Jan 2017 22:28:56 -0500 In-Reply-To: <1485829518-190263-1-git-send-email-ast@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2017-01-30 at 18:25 -0800, Alexei Starovoitov wrote: > under memory pressure 'ethtool -S' command may warn: > [ 2374.385195] ethtool: page allocation failure: order:4, mode:0x242c0c0 > [ 2374.405573] CPU: 12 PID: 40211 Comm: ethtool Not tainted > [ 2374.423071] Call Trace: > [ 2374.423076] [] dump_stack+0x4d/0x64 > [ 2374.423080] [] warn_alloc_failed+0xeb/0x150 > [ 2374.423082] [] ? __alloc_pages_direct_compact+0x43/0xf0 > [ 2374.423084] [] __alloc_pages_nodemask+0x4dc/0xbf0 > [ 2374.423091] [] ? cmd_exec+0x722/0xcd0 [mlx5_core] > [ 2374.423095] [] alloc_pages_current+0x8c/0x110 > [ 2374.423097] [] alloc_kmem_pages+0x19/0x90 > [ 2374.423099] [] kmalloc_order_trace+0x2e/0xe0 > [ 2374.423101] [] __kmalloc+0x204/0x220 > [ 2374.423105] [] dev_ethtool+0xe4e/0x1f80 > [ 2374.423106] [] ? dev_get_by_name_rcu+0x5e/0x80 > [ 2374.423108] [] dev_ioctl+0x156/0x560 > [ 2374.423111] [] ? mem_cgroup_commit_charge+0x78/0x3c0 > [ 2374.423117] [] sock_do_ioctl+0x42/0x50 > [ 2374.423119] [] sock_ioctl+0x1b3/0x250 > [ 2374.423121] [] do_vfs_ioctl+0x92/0x580 > [ 2374.423123] [] ? do_audit_syscall_entry+0x4b/0x70 > [ 2374.423124] [] ? syscall_trace_enter_phase1+0xfc/0x120 > [ 2374.423126] [] SyS_ioctl+0x79/0x90 > [ 2374.423127] [] do_syscall_64+0x50/0xa0 > [ 2374.423129] [] entry_SYSCALL64_slow_path+0x25/0x25 > > ~1160 mlx5 counters ~= order 4 allocation which is unlikely to succeed > under memory pressure. Convert them to vzalloc() as ethtool_get_regs() does. > Also take care of drivers without counters similar to > commit 67ae7cf1eeda ("ethtool: Allow zero-length register dumps again") > and reduce warn_on to warn_on_once. I think this is generally not a good idea as most uses already fit fine in a kcalloc. Maybe use Michal Hocko's kvmalloc changes. https://lkml.org/lkml/2017/1/30/120