From patchwork Thu Nov 12 13:37:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11900253 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D551E921 for ; Thu, 12 Nov 2020 13:39:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8B6FF22240 for ; Thu, 12 Nov 2020 13:39:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gCiDgAPq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8B6FF22240 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 79B9C6B007E; Thu, 12 Nov 2020 08:39:00 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 6F26D6B0080; Thu, 12 Nov 2020 08:39:00 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 55AC46B0081; Thu, 12 Nov 2020 08:39:00 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 19CBB6B007E for ; Thu, 12 Nov 2020 08:39:00 -0500 (EST) Received: from smtpin14.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B62543625 for ; Thu, 12 Nov 2020 13:38:59 +0000 (UTC) X-FDA: 77475871998.14.spy43_070ee8027306 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin14.hostedemail.com (Postfix) with ESMTP id 9427F18229818 for ; Thu, 12 Nov 2020 13:38:59 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,david@redhat.com,,RULES_HIT:30054:30070,0,RBL:216.205.24.124:@redhat.com:.lbl8.mailshell.net-64.10.201.10 62.18.0.100;04ygtrd7f6r14y7x8wwj8ohio8rjiypjtumn3f4sbhc15dbup8nftda8ohb5h8x.h4m85tuskht7sey1yafiusttazc1qpccs4hmc8s4qfeg1hhoxtfep7cfkichdtw.y-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:70,LUA_SUMMARY:none X-HE-Tag: spy43_070ee8027306 X-Filterd-Recvd-Size: 4429 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Thu, 12 Nov 2020 13:38:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605188338; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=s7b/l63zYUaR+OsccnXVvZ/uAYcvm6kvDksVTa1Mbhc=; b=gCiDgAPq0SH0Io4YxY7kuIsYvQf5Uych1NSILLIlIgDr0frXqi8VIAZ1t+6X8uzw+geoL6 YLt3ebPdJNP+yXlsAW6UaYBO0UkS/iZVKAs/qgoiL+xz/ROgbTlQYit9zJQvfaZsspZqsc GmQ/Tcs6g2Ghd7BDiLMc9Rtp1XFTXCc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-19-IhACjZgxNUGOglFtNSkyqg-1; Thu, 12 Nov 2020 08:38:54 -0500 X-MC-Unique: IhACjZgxNUGOglFtNSkyqg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5257018BA282; Thu, 12 Nov 2020 13:38:53 +0000 (UTC) Received: from t480s.redhat.com (ovpn-115-61.ams2.redhat.com [10.36.115.61]) by smtp.corp.redhat.com (Postfix) with ESMTP id C589655765; Thu, 12 Nov 2020 13:38:51 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, "Michael S . Tsirkin" , David Hildenbrand , Jason Wang , Pankaj Gupta Subject: [PATCH v2 10/29] virtio-mem: retry fake-offlining via alloc_contig_range() on ZONE_MOVABLE Date: Thu, 12 Nov 2020 14:37:56 +0100 Message-Id: <20201112133815.13332-11-david@redhat.com> In-Reply-To: <20201112133815.13332-1-david@redhat.com> References: <20201112133815.13332-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: ZONE_MOVABLE is supposed to give some guarantees, yet, alloc_contig_range() isn't prepared to properly deal with some racy cases properly (e.g., temporary page pinning when exiting processed, PCP). Retry 5 times for now. There is certainly room for improvement in the future. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Pankaj Gupta Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index c24055248f9d..2f1ce4d4781b 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -784,19 +784,34 @@ static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages) */ static int virtio_mem_fake_offline(unsigned long pfn, unsigned long nr_pages) { - int rc; + const bool is_movable = zone_idx(page_zone(pfn_to_page(pfn))) == + ZONE_MOVABLE; + int rc, retry_count; - rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE, - GFP_KERNEL); - if (rc == -ENOMEM) - /* whoops, out of memory */ - return rc; - if (rc) - return -EBUSY; + /* + * TODO: We want an alloc_contig_range() mode that tries to allocate + * harder (e.g., dealing with temporarily pinned pages, PCP), especially + * with ZONE_MOVABLE. So for now, retry a couple of times with + * ZONE_MOVABLE before giving up - because that zone is supposed to give + * some guarantees. + */ + for (retry_count = 0; retry_count < 5; retry_count++) { + rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE, + GFP_KERNEL); + if (rc == -ENOMEM) + /* whoops, out of memory */ + return rc; + else if (rc && !is_movable) + break; + else if (rc) + continue; - virtio_mem_set_fake_offline(pfn, nr_pages, true); - adjust_managed_page_count(pfn_to_page(pfn), -nr_pages); - return 0; + virtio_mem_set_fake_offline(pfn, nr_pages, true); + adjust_managed_page_count(pfn_to_page(pfn), -nr_pages); + return 0; + } + + return -EBUSY; } /*