Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755712AbbGPPwQ (ORCPT ); Thu, 16 Jul 2015 11:52:16 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:36559 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755607AbbGPPwL (ORCPT ); Thu, 16 Jul 2015 11:52:11 -0400 Subject: Re: [RFC 2/3] arm64: refactor save_stack_trace() Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Jungseok Lee In-Reply-To: <20150716113115.45a17f17@gandalf.local.home> Date: Fri, 17 Jul 2015 00:52:04 +0900 Cc: AKASHI Takahiro , catalin.marinas@arm.com, will.deacon@arm.com, olof@lixom.net, broonie@kernel.org, david.griego@linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 7bit Message-Id: <5176E676-1AAA-4F2B-827B-BEF3A2620D86@gmail.com> References: <1436765375-7119-1-git-send-email-takahiro.akashi@linaro.org> <1436765375-7119-3-git-send-email-takahiro.akashi@linaro.org> <20150714093154.4d73e551@gandalf.local.home> <55A5A75A.1060401@linaro.org> <20150714225105.6c1e4f15@gandalf.local.home> <55A646EE.6030402@linaro.org> <20150715105536.42949ea9@gandalf.local.home> <20150715121337.3b31aa84@gandalf.local.home> <55A6FA82.9000901@linaro.org> <55A703F3.8050203@linaro.org> <20150716102405.2cc8c406@gandalf.local.home> <12F47692-3010-4886-B87D-3D7820609177@gmail.com> <20150716113115.45a17f17@gandalf.local.home> To: Steven Rostedt X-Mailer: Apple Mail (2.1283) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5499 Lines: 134 On Jul 17, 2015, at 12:31 AM, Steven Rostedt wrote: > On Fri, 17 Jul 2015 00:01:25 +0900 > Jungseok Lee wrote: > >> I've gathered stack tracer data with your update. >> >> 1) stack_trace >> Depth Size Location (35 entries) >> ----- ---- -------- >> 0) 4424 16 put_cpu_partial+0x28/0x1d0 >> 1) 4408 80 get_partial_node.isra.64+0x13c/0x344 >> 2) 4328 256 __slab_alloc.isra.65.constprop.67+0xd8/0x37c >> 3) 4072 32 kmem_cache_alloc+0x258/0x294 >> 4) 4040 304 __alloc_skb+0x48/0x180 >> 5) 3736 96 alloc_skb_with_frags+0x74/0x234 >> 6) 3640 112 sock_alloc_send_pskb+0x1d0/0x294 >> 7) 3528 160 sock_alloc_send_skb+0x44/0x54 >> 8) 3368 64 __ip_append_data.isra.40+0x78c/0xb48 >> 9) 3304 224 ip_append_data.part.42+0x98/0xe8 >> 10) 3080 112 ip_append_data+0x68/0x7c >> 11) 2968 96 icmp_push_reply+0x7c/0x144 >> 12) 2872 96 icmp_send+0x3c0/0x3c8 >> 13) 2776 192 __udp4_lib_rcv+0x5b8/0x684 >> 14) 2584 96 udp_rcv+0x2c/0x3c >> 15) 2488 32 ip_local_deliver+0xa0/0x224 >> 16) 2456 48 ip_rcv+0x360/0x57c >> 17) 2408 64 __netif_receive_skb_core+0x4d0/0x80c >> 18) 2344 128 __netif_receive_skb+0x24/0x84 >> 19) 2216 32 process_backlog+0x9c/0x15c >> 20) 2184 80 net_rx_action+0x1ec/0x32c >> 21) 2104 160 __do_softirq+0x114/0x2f0 >> 22) 1944 128 do_softirq+0x60/0x68 >> 23) 1816 32 __local_bh_enable_ip+0xb0/0xd4 >> 24) 1784 32 ip_finish_output+0x1f4/0xabc >> 25) 1752 96 ip_output+0xf0/0x120 >> 26) 1656 64 ip_local_out_sk+0x44/0x54 >> 27) 1592 32 ip_send_skb+0x24/0xbc >> 28) 1560 48 udp_send_skb+0x1b4/0x2f4 >> 29) 1512 80 udp_sendmsg+0x2a8/0x7a0 >> 30) 1432 272 inet_sendmsg+0xa0/0xd0 >> 31) 1160 48 sock_sendmsg+0x30/0x78 >> 32) 1112 32 ___sys_sendmsg+0x15c/0x26c >> 33) 1080 400 __sys_sendmmsg+0x94/0x180 >> 34) 680 320 SyS_sendmmsg+0x38/0x54 >> 35) 360 360 el0_svc_naked+0x20/0x28 >> >> 2) stack_max_size >> 4504 > > Strange, on x86 I have this (with my patch applied): > > Depth Size Location (39 entries) > ----- ---- -------- > 0) 3704 64 _raw_spin_lock+0x5/0x30 > 1) 3640 200 get_partial_node.isra.80+0x54/0x1da > 2) 3440 208 __slab_alloc.isra.82+0x199/0x3f7 > 3) 3232 80 kmem_cache_alloc+0x151/0x160 > 4) 3152 16 mempool_alloc_slab+0x15/0x20 > 5) 3136 128 mempool_alloc+0x58/0x150 > 6) 3008 16 scsi_sg_alloc+0x42/0x50 > 7) 2992 112 __sg_alloc_table+0x10b/0x150 > 8) 2880 48 scsi_alloc_sgtable+0x43/0x80 > 9) 2832 32 scsi_init_sgtable+0x2b/0x70 > 10) 2800 80 scsi_init_io+0x59/0x1e0 > 11) 2720 128 sd_init_command+0x66/0xd80 > 12) 2592 24 scsi_setup_cmnd+0xa9/0x160 > 13) 2568 88 scsi_prep_fn+0x7d/0x160 > 14) 2480 48 blk_peek_request+0x168/0x2a0 > 15) 2432 112 scsi_request_fn+0x3f/0x610 > 16) 2320 8 __blk_run_queue+0x37/0x50 > 17) 2312 104 queue_unplugged+0x41/0xe0 > 18) 2208 112 blk_flush_plug_list+0x1b7/0x1e0 > 19) 2096 80 blk_queue_bio+0x257/0x340 > 20) 2016 48 generic_make_request+0xb1/0xf0 > 21) 1968 96 submit_bio+0x76/0x130 > 22) 1872 48 submit_bh_wbc.isra.35+0x10b/0x140 > 23) 1824 112 __block_write_full_page.constprop.40+0x188/0x310 > 24) 1712 64 block_write_full_page+0xdd/0x130 > 25) 1648 16 blkdev_writepage+0x18/0x20 > 26) 1632 8 __writepage+0x17/0x40 > 27) 1624 312 write_cache_pages+0x21e/0x480 > 28) 1312 96 generic_writepages+0x4a/0x70 > 29) 1216 16 do_writepages+0x20/0x30 > 30) 1200 96 __writeback_single_inode+0x45/0x350 > 31) 1104 176 writeback_sb_inodes+0x218/0x3d0 > 32) 928 80 __writeback_inodes_wb+0x8c/0xc0 > 33) 848 128 wb_writeback+0x239/0x2c0 > 34) 720 192 wb_workfn+0x24b/0x460 > 35) 528 80 process_one_work+0x14b/0x430 > 36) 448 128 worker_thread+0x117/0x460 > 37) 320 144 kthread+0xc9/0xe0 > 38) 176 176 ret_from_fork+0x3f/0x70 > > # cat /debug/tracing/stack_max_size > 3704 > > >> >> In case of the number of entries, the following diff might be needed >> as I suggested in the previous reply. ;) >> >> ----8<---- >> >> @@ -330,7 +333,7 @@ static int t_show(struct seq_file *m, void *v) >> seq_printf(m, " Depth Size Location" >> " (%d entries)\n" >> " ----- ---- --------\n", >> - max_stack_trace.nr_entries - 1); >> + max_stack_trace.nr_entries); > > This would break x86. Thanks for x86 data. It's really helpful! > >> >> if (!stack_tracer_enabled && !max_stack_size) >> print_disabled(m); >> >> ----8<---- >> >> However, 80-byte gap still appears. > > This seems to be specific to your arch. Totally agree. Best Regards Jungseok Lee -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/