From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) by kanga.kvack.org (Postfix) with ESMTP id 8857A6B5535 for ; Thu, 29 Nov 2018 18:49:59 -0500 (EST) Received: by mail-ed1-f70.google.com with SMTP id q8so1900583edd.8 for ; Thu, 29 Nov 2018 15:49:59 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id q9sor2245447eda.25.2018.11.29.15.49.57 for (Google Transport Security); Thu, 29 Nov 2018 15:49:58 -0800 (PST) Date: Thu, 29 Nov 2018 23:49:56 +0000 From: Wei Yang Subject: Re: [PATCH] mm, show_mem: drop pgdat_resize_lock in show_mem() Message-ID: <20181129234956.vdlz5hkfxoawda4y@master> Reply-To: Wei Yang References: <20181128210815.2134-1-richard.weiyang@gmail.com> <20181129081703.GN6923@dhcp22.suse.cz> <20181129150449.desiutez735agyau@master> <20181129154922.GT6923@dhcp22.suse.cz> <20181129160524.ewjn2x7spyloitu4@master> <20181129161847.GU6923@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181129161847.GU6923@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Wei Yang , akpm@linux-foundation.org, jweiner@fb.com, linux-mm@kvack.org On Thu, Nov 29, 2018 at 05:18:47PM +0100, Michal Hocko wrote: >On Thu 29-11-18 16:05:24, Wei Yang wrote: >> On Thu, Nov 29, 2018 at 04:49:22PM +0100, Michal Hocko wrote: >[...] >> >It is only called from __remove_pages and that one calls cond_resched so >> >obviosly not. >> > >> >> Forgive my poor background knowledge, I went throught the code, but not >> found where call cond_resched. >> >> __remove_pages() >> release_mem_region_adjustable() >> clear_zone_contiguous() >> __remove_section() >> unregister_memory_section() >> __remove_zone() >> sparse_remove_one_section() >> set_zone_contiguous() >> >> Would you mind giving me a hint? > >This is the code as of 4.20-rc2 > > for (i = 0; i < sections_to_remove; i++) { > unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; > > cond_resched(); > ret = __remove_section(zone, __pfn_to_section(pfn), map_offset, > altmap); > map_offset = 0; > if (ret) > break; > } > >Maybe things have changed in the meantime but in general the code is >sleepable (e.g. release_mem_region_adjustable does GFP_KERNEL >allocation) and that rules out IRQ context. Thanks, my code is not up to date. >-- >Michal Hocko >SUSE Labs -- Wei Yang Help you, Help me