From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08BC7C4708F for ; Wed, 2 Jun 2021 18:57:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5E7F613DE for ; Wed, 2 Jun 2021 18:57:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229790AbhFBS7l (ORCPT ); Wed, 2 Jun 2021 14:59:41 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:32434 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229775AbhFBS7j (ORCPT ); Wed, 2 Jun 2021 14:59:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1622660276; 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=opX8nHoEd36stvd7Apu9m63irxvh9gxuAe97ioC+BQQ=; b=fD48NnEuvCPuC4yiQh0nDutL1zJ8q0/wHyqh0PCVdy43bTntmiurHrLCjsJLLi5U1QQGSm Zu8jEkBiNdweYtlaBG3XVGQCYbXWwVTATGw5P/VqKFGFwSb4GDLRhR019dKBmW3bf7jUME n3cqfZDir+u/3Pt+76qSDb9c8R/WMso= 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-471-yPJ8YLn9PiC5J6o7nhb5Lg-1; Wed, 02 Jun 2021 14:57:54 -0400 X-MC-Unique: yPJ8YLn9PiC5J6o7nhb5Lg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1C90E180FD64; Wed, 2 Jun 2021 18:57:53 +0000 (UTC) Received: from t480s.redhat.com (ovpn-114-159.ams2.redhat.com [10.36.114.159]) by smtp.corp.redhat.com (Postfix) with ESMTP id 70247100238C; Wed, 2 Jun 2021 18:57:50 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , "Michael S. Tsirkin" , Jason Wang , Marek Kedzierski , Hui Zhu , Pankaj Gupta , Wei Yang , Oscar Salvador , Michal Hocko , virtualization@lists.linux-foundation.org, linux-mm@kvack.org Subject: [PATCH v1 4/7] virtio-mem: simplify high-level unplug handling in Sub Block Mode Date: Wed, 2 Jun 2021 20:57:17 +0200 Message-Id: <20210602185720.31821-5-david@redhat.com> In-Reply-To: <20210602185720.31821-1-david@redhat.com> References: <20210602185720.31821-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Let's simplify by introducing a new virtio_mem_sbm_unplug_any_sb(), similar to virtio_mem_sbm_plug_any_sb(), to simplify high-level memory block selection when unplugging in Sub Block Mode. Rename existing virtio_mem_sbm_unplug_any_sb() to virtio_mem_sbm_unplug_any_sb_raw(). The only change is that we now temporarily unlock the hotplug mutex around cond_resched() when processing offline memory blocks, which doesn't make a real difference as we already have to temporarily unlock in virtio_mem_sbm_unplug_any_sb_offline() when removing a memory block. Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 103 ++++++++++++++++++++---------------- 1 file changed, 57 insertions(+), 46 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index c0e6ea6244e4..d54bb34a7ed8 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -1453,8 +1453,8 @@ static int virtio_mem_bbm_plug_bb(struct virtio_mem *vm, unsigned long bb_id) * * Note: can fail after some subblocks were unplugged. */ -static int virtio_mem_sbm_unplug_any_sb(struct virtio_mem *vm, - unsigned long mb_id, uint64_t *nb_sb) +static int virtio_mem_sbm_unplug_any_sb_raw(struct virtio_mem *vm, + unsigned long mb_id, uint64_t *nb_sb) { int sb_id, count; int rc; @@ -1496,7 +1496,7 @@ static int virtio_mem_sbm_unplug_mb(struct virtio_mem *vm, unsigned long mb_id) { uint64_t nb_sb = vm->sbm.sbs_per_mb; - return virtio_mem_sbm_unplug_any_sb(vm, mb_id, &nb_sb); + return virtio_mem_sbm_unplug_any_sb_raw(vm, mb_id, &nb_sb); } /* @@ -1806,7 +1806,7 @@ static int virtio_mem_sbm_unplug_any_sb_offline(struct virtio_mem *vm, { int rc; - rc = virtio_mem_sbm_unplug_any_sb(vm, mb_id, nb_sb); + rc = virtio_mem_sbm_unplug_any_sb_raw(vm, mb_id, nb_sb); /* some subblocks might have been unplugged even on failure */ if (!virtio_mem_sbm_test_sb_plugged(vm, mb_id, 0, vm->sbm.sbs_per_mb)) @@ -1929,11 +1929,46 @@ static int virtio_mem_sbm_unplug_any_sb_online(struct virtio_mem *vm, return 0; } +/* + * Unplug the desired number of plugged subblocks of a memory block that is + * already added to Linux. Will skip subblock of online memory blocks that are + * busy (by the OS). Will fail if any subblock that's not busy cannot get + * unplugged. + * + * Will modify the state of the memory block. Might temporarily drop the + * hotplug_mutex. + * + * Note: Can fail after some subblocks were successfully unplugged. Can + * return 0 even if subblocks were busy and could not get unplugged. + */ +static int virtio_mem_sbm_unplug_any_sb(struct virtio_mem *vm, + unsigned long mb_id, + uint64_t *nb_sb) +{ + const int old_state = virtio_mem_sbm_get_mb_state(vm, mb_id); + + switch (old_state) { + case VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL: + case VIRTIO_MEM_SBM_MB_ONLINE: + return virtio_mem_sbm_unplug_any_sb_online(vm, mb_id, nb_sb); + case VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL: + case VIRTIO_MEM_SBM_MB_OFFLINE: + return virtio_mem_sbm_unplug_any_sb_offline(vm, mb_id, nb_sb); + } + return -EINVAL; +} + static int virtio_mem_sbm_unplug_request(struct virtio_mem *vm, uint64_t diff) { + const int mb_states[] = { + VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL, + VIRTIO_MEM_SBM_MB_OFFLINE, + VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL, + VIRTIO_MEM_SBM_MB_ONLINE, + }; uint64_t nb_sb = diff / vm->sbm.sb_size; unsigned long mb_id; - int rc; + int rc, i; if (!nb_sb) return 0; @@ -1945,47 +1980,23 @@ static int virtio_mem_sbm_unplug_request(struct virtio_mem *vm, uint64_t diff) */ mutex_lock(&vm->hotplug_mutex); - /* Try to unplug subblocks of partially plugged offline blocks. */ - virtio_mem_sbm_for_each_mb_rev(vm, mb_id, - VIRTIO_MEM_SBM_MB_OFFLINE_PARTIAL) { - rc = virtio_mem_sbm_unplug_any_sb_offline(vm, mb_id, &nb_sb); - if (rc || !nb_sb) - goto out_unlock; - cond_resched(); - } - - /* Try to unplug subblocks of plugged offline blocks. */ - virtio_mem_sbm_for_each_mb_rev(vm, mb_id, VIRTIO_MEM_SBM_MB_OFFLINE) { - rc = virtio_mem_sbm_unplug_any_sb_offline(vm, mb_id, &nb_sb); - if (rc || !nb_sb) - goto out_unlock; - cond_resched(); - } - - if (!unplug_online) { - mutex_unlock(&vm->hotplug_mutex); - return 0; - } - - /* Try to unplug subblocks of partially plugged online blocks. */ - virtio_mem_sbm_for_each_mb_rev(vm, mb_id, - VIRTIO_MEM_SBM_MB_ONLINE_PARTIAL) { - rc = virtio_mem_sbm_unplug_any_sb_online(vm, mb_id, &nb_sb); - if (rc || !nb_sb) - goto out_unlock; - mutex_unlock(&vm->hotplug_mutex); - cond_resched(); - mutex_lock(&vm->hotplug_mutex); - } - - /* Try to unplug subblocks of plugged online blocks. */ - virtio_mem_sbm_for_each_mb_rev(vm, mb_id, VIRTIO_MEM_SBM_MB_ONLINE) { - rc = virtio_mem_sbm_unplug_any_sb_online(vm, mb_id, &nb_sb); - if (rc || !nb_sb) - goto out_unlock; - mutex_unlock(&vm->hotplug_mutex); - cond_resched(); - mutex_lock(&vm->hotplug_mutex); + /* + * We try unplug from partially plugged blocks first, to try removing + * whole memory blocks along with metadata. + */ + for (i = 0; i < ARRAY_SIZE(mb_states); i++) { + virtio_mem_sbm_for_each_mb_rev(vm, mb_id, mb_states[i]) { + rc = virtio_mem_sbm_unplug_any_sb(vm, mb_id, &nb_sb); + if (rc || !nb_sb) + goto out_unlock; + mutex_unlock(&vm->hotplug_mutex); + cond_resched(); + mutex_lock(&vm->hotplug_mutex); + } + if (!unplug_online && i == 1) { + mutex_unlock(&vm->hotplug_mutex); + return 0; + } } mutex_unlock(&vm->hotplug_mutex); -- 2.31.1