From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yb1-f200.google.com (mail-yb1-f200.google.com [209.85.219.200]) by kanga.kvack.org (Postfix) with ESMTP id C05326B0008 for ; Tue, 16 Oct 2018 05:35:02 -0400 (EDT) Received: by mail-yb1-f200.google.com with SMTP id n8-v6so12543544ybo.9 for ; Tue, 16 Oct 2018 02:35:02 -0700 (PDT) Received: from hqemgate16.nvidia.com (hqemgate16.nvidia.com. [216.228.121.65]) by mx.google.com with ESMTPS id e133-v6si4028712ywb.57.2018.10.16.02.35.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Oct 2018 02:35:01 -0700 (PDT) Subject: Re: [PATCH] mm: Avoid swapping in interrupt context References: <1538387115-2363-1-git-send-email-amhetre@nvidia.com> <20181001122400.GF18290@dhcp22.suse.cz> <988dfe01-6553-1e0a-1d98-1b3d3aa67517@nvidia.com> <20181003110146.GB4714@dhcp22.suse.cz> <20181003115314.GE4714@dhcp22.suse.cz> From: Ashish Mhetre Message-ID: Date: Tue, 16 Oct 2018 15:05:00 +0530 MIME-Version: 1.0 In-Reply-To: <20181003115314.GE4714@dhcp22.suse.cz> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, akpm@linux-foundation.org, vdumpa@nvidia.com, Snikam@nvidia.com Sorry for the delayed response. Yes, you are correct. There is no call from IRQ in dump. I take back our assertion. Thanks for the insights. On Wednesday 03 October 2018 05:23 PM, Michal Hocko wrote: > On Wed 03-10-18 17:20:15, Ashish Mhetre wrote: >>> This doesn't show the backtrace part which contains the allocation >> AFAICS. >> >> My bad. Here is a complete dump: >> [ 264.082531] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM >> [ 264.088350] Modules linked in: >> [ 264.091406] CPU: 0 PID: 3805 Comm: kworker/0:4 Tainted: G W >> 3.10.33-g990282b #1 >> [ 264.099572] Workqueue: events netstat_work_func >> [ 264.104097] task: e7b12040 ti: dc7d4000 task.ti: dc7d4000 >> [ 264.109485] PC is at zs_map_object+0x180/0x18c >> [ 264.113918] LR is at zram_bvec_rw.isra.15+0x304/0x88c >> [ 264.118956] pc : [] lr : [] psr: 200f0013 >> [ 264.118956] sp : dc7d5460 ip : fff00814 fp : 00000002 >> [ 264.130407] r10: ea8ec000 r9 : ebc93340 r8 : 00000000 >> [ 264.135618] r7 : c191502c r6 : dc7d4020 r5 : d25f5684 r4 : ec3158c0 >> [ 264.142128] r3 : 00000200 r2 : 00000002 r1 : c191502c r0 : ea8ec000 >> >> -------- >> [ 265.772426] [] (zs_map_object+0x180/0x18c) from [] >> (zram_bvec_rw.isra.15+0x304/0x88c) >> [ 265.781973] [] (zram_bvec_rw.isra.15+0x304/0x88c) from >> [] (zram_make_request+0x1d8/0x378) >> [ 265.791868] [] (zram_make_request+0x1d8/0x378) from [] >> (generic_make_request+0xb0/0xdc) >> [ 265.801588] [] (generic_make_request+0xb0/0xdc) from >> [] (submit_bio+0x88/0x140) >> [ 265.810617] [] (submit_bio+0x88/0x140) from [] >> (__swap_writepage+0x198/0x230) >> [ 265.819471] [] (__swap_writepage+0x198/0x230) from [] >> (shrink_page_list+0x4e0/0x974) >> [ 265.828930] [] (shrink_page_list+0x4e0/0x974) from [] >> (shrink_inactive_list+0x150/0x3c8) >> [ 265.838736] [] (shrink_inactive_list+0x150/0x3c8) from >> [] (shrink_lruvec+0x20c/0x448) >> [ 265.848282] [] (shrink_lruvec+0x20c/0x448) from [] >> (shrink_zone+0x78/0x188) >> [ 265.856960] [] (shrink_zone+0x78/0x188) from [] >> (do_try_to_free_pages+0x100/0x544) >> [ 265.866246] [] (do_try_to_free_pages+0x100/0x544) from >> [] (try_to_free_pages+0x238/0x428) >> [ 265.876140] [] (try_to_free_pages+0x238/0x428) from [] >> (__alloc_pages_nodemask+0x5b0/0x90c) >> [ 265.886207] [] (__alloc_pages_nodemask+0x5b0/0x90c) from >> [] (__get_free_pages+0x1c/0x34) >> [ 265.896014] [] (__get_free_pages+0x1c/0x34) from [] >> (tcp4_seq_show+0x248/0x4b4) >> [ 265.905042] [] (tcp4_seq_show+0x248/0x4b4) from [] >> (seq_read+0x1e4/0x484) >> [ 265.913550] [] (seq_read+0x1e4/0x484) from [] >> (proc_reg_read+0x60/0x88) >> [ 265.921884] [] (proc_reg_read+0x60/0x88) from [] >> (vfs_read+0xa0/0x14c) >> [ 265.930129] [] (vfs_read+0xa0/0x14c) from [] >> (SyS_read+0x44/0x80) >> [ 265.937942] [] (SyS_read+0x44/0x80) from [] >> (netstat_work_func+0x54/0xec) >> [ 265.946450] [] (netstat_work_func+0x54/0xec) from [] >> (process_one_work+0x13c/0x454) >> [ 265.955823] [] (process_one_work+0x13c/0x454) from [] >> (worker_thread+0x140/0x3dc) >> 265.965022] [] (worker_thread+0x140/0x3dc) from [] >> (kthread+0xe0/0xe4) >> [ 265.973269] [] (kthread+0xe0/0xe4) from [] >> (ret_from_fork+0x14/0x20) >> [ 264.148640] Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel >> [ 264.155930] Control: 30c5387d Table: aaf7c000 DAC: fffffffd > This looks like a regular syscall path. How have you concluded this is > due to an IRQ context?