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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A5B00C48BF6 for ; Mon, 26 Feb 2024 07:54:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1reVoJ-0007uG-WC; Mon, 26 Feb 2024 02:54:04 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1reVoI-0007tr-9E for qemu-devel@nongnu.org; Mon, 26 Feb 2024 02:54:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1reVoG-0007Zm-Hx for qemu-devel@nongnu.org; Mon, 26 Feb 2024 02:54:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708934039; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Hk7dSEBryHIDCofaYXYpeWn4dS5T/dFcicxkPJYXiCg=; b=ZYGwfkXOtKZPayzWmfVmpqji5Bz1ghMrBJHeNM0vku+Hxht6z5b6fqLuIlPEUSdwhKZdqJ z+8+SmMx5dNEehJ0rT4Mozl/8wmCwt1JRs1YhasvraD6OjlS69rycjRvt9SISvSOJnK/jT 8GajvI4VuY5rUboz74qR0nuydC8fi2g= Received: from mail-pg1-f200.google.com (mail-pg1-f200.google.com [209.85.215.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-28-hdsKY_t0MSa8D9uelmCCwg-1; Mon, 26 Feb 2024 02:53:57 -0500 X-MC-Unique: hdsKY_t0MSa8D9uelmCCwg-1 Received: by mail-pg1-f200.google.com with SMTP id 41be03b00d2f7-5dc97ac2facso1310537a12.0 for ; Sun, 25 Feb 2024 23:53:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708934036; x=1709538836; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=Hk7dSEBryHIDCofaYXYpeWn4dS5T/dFcicxkPJYXiCg=; b=pkaBma6Z7nOlY0ZSZbq8QNt9wbmgfEEHckePNAnCQOXchKx0CyC734NsThgQEHhAbP kjlff/VhW2ibNCMCVs0mP6tetvkgkDPqPXT4asivQzKuHzaIxjBCTAnFNjXESRWevncq iRc7fBO5t+7ZYyvm9J7brMVWx4+q3XuDp4QtuebTyHN158wicU6qsDRZPLcMdjTHxejW kk93sbJKTqMvPpPmjB6kVI3h3pqFAGBJqhNW4htr/mD3XvfCkltkqkbvS5mmG6FDvE4I XZRihyt68gIgMRq4rxY74f6QQ0mIsyqF0TQqCpcPHMWY7n2depbVWGAookt2uliptOyw /SEg== X-Gm-Message-State: AOJu0YyQsUn5nGdsZ6hZz3KFLU97j01kgmwEl8k/WSOYx5ZK1cZ9xhO2 kLaGXmvtuAO8yJoIKA99yN7t8vtq2nY0I1nT2RRjkliofm4bqPyV0yvNYWxrWitS3/DJUXjJIPA YsEeWRi3VGr1DGBGp7gHI8/WfxDIQUNjLwy7TFHXpjlQCmGB4JXZ4OZ0rVFr6tj8= X-Received: by 2002:a05:6a00:2d14:b0:6e4:fe18:9528 with SMTP id fa20-20020a056a002d1400b006e4fe189528mr6317715pfb.3.1708934035774; Sun, 25 Feb 2024 23:53:55 -0800 (PST) X-Google-Smtp-Source: AGHT+IFSL8tpeuDH9HwSNUyKOitxN5Chk2+9m3IAdUUuRXln7CBcHZRNzPLO6nhRx/T60Qon2MFv9g== X-Received: by 2002:a05:6a00:2d14:b0:6e4:fe18:9528 with SMTP id fa20-20020a056a002d1400b006e4fe189528mr6317705pfb.3.1708934035417; Sun, 25 Feb 2024 23:53:55 -0800 (PST) Received: from x1n ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id t14-20020a056a0021ce00b006e04ca18c2bsm3382871pfj.196.2024.02.25.23.53.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 25 Feb 2024 23:53:55 -0800 (PST) Date: Mon, 26 Feb 2024 15:53:48 +0800 From: Peter Xu To: Fabiano Rosas Cc: qemu-devel@nongnu.org, berrange@redhat.com, armbru@redhat.com, Claudio Fontana Subject: Re: [PATCH v4 21/34] migration/multifd: Add incoming QIOChannelFile support Message-ID: References: <20240220224138.24759-1-farosas@suse.de> <20240220224138.24759-22-farosas@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.097, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Feb 26, 2024 at 03:34:26PM +0800, Peter Xu wrote: > On Tue, Feb 20, 2024 at 07:41:25PM -0300, Fabiano Rosas wrote: > > On the receiving side we don't need to differentiate between main > > channel and threads, so whichever channel is defined first gets to be > > the main one. And since there are no packets, use the atomic channel > > count to index into the params array. > > > > Signed-off-by: Fabiano Rosas > > --- > > migration/file.c | 34 ++++++++++++++++++++++++++-------- > > migration/migration.c | 3 ++- > > migration/multifd.c | 3 +-- > > 3 files changed, 29 insertions(+), 11 deletions(-) > > > > diff --git a/migration/file.c b/migration/file.c > > index ac9f6ae40a..a186dc592a 100644 > > --- a/migration/file.c > > +++ b/migration/file.c > > @@ -8,6 +8,7 @@ > > #include "qemu/osdep.h" > > #include "exec/ramblock.h" > > #include "qemu/cutils.h" > > +#include "qemu/error-report.h" > > #include "qapi/error.h" > > #include "channel.h" > > #include "file.h" > > @@ -15,6 +16,7 @@ > > #include "multifd.h" > > #include "io/channel-file.h" > > #include "io/channel-util.h" > > +#include "options.h" > > #include "trace.h" > > > > #define OFFSET_OPTION ",offset=" > > @@ -111,7 +113,8 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp) > > g_autofree char *filename = g_strdup(file_args->filename); > > QIOChannelFile *fioc = NULL; > > uint64_t offset = file_args->offset; > > - QIOChannel *ioc; > > + int channels = 1; > > + int i = 0, fd; > > > > trace_migration_file_incoming(filename); > > > > @@ -120,13 +123,28 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp) > > return; > > } > > > > - ioc = QIO_CHANNEL(fioc); > > - if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) { > > + if (offset && > > + qio_channel_io_seek(QIO_CHANNEL(fioc), offset, SEEK_SET, errp) < 0) { > > return; > > } > > - qio_channel_set_name(QIO_CHANNEL(ioc), "migration-file-incoming"); > > - qio_channel_add_watch_full(ioc, G_IO_IN, > > - file_accept_incoming_migration, > > - NULL, NULL, > > - g_main_context_get_thread_default()); > > + > > + if (migrate_multifd()) { > > + channels += migrate_multifd_channels(); > > + } > > + > > + fd = fioc->fd; > > + > > + do { > > + QIOChannel *ioc = QIO_CHANNEL(fioc); > > + > > + qio_channel_set_name(ioc, "migration-file-incoming"); > > + qio_channel_add_watch_full(ioc, G_IO_IN, > > + file_accept_incoming_migration, > > + NULL, NULL, > > + g_main_context_get_thread_default()); > > + } while (++i < channels && (fioc = qio_channel_file_new_fd(fd))); > > Note that reusing fd here has similar risk in the future that one iochannel > can affect the other, as potentially all shares the same fd underneath; I > think it's the same as "two qemufile v.s. one iochannel" issue that we're > fighting recently. > > IIUC the clean case is still that we open one fd for each iochannel. Or > e.g. as long as one iochannel close() its fd, it immediately invalidates > all the rest iochannels on something like use-after-free of that fd index; > any fd operates races with another fd being opened concurrently. > > Maybe we can already use a loop of qio_channel_file_new_path()? OS should > already cached the dentry etc. so I assume the following ones should be > super fast? Or there's other complexities that I didn't aware? Or simply use dup()? > > > + > > + if (!fioc) { > > + error_setg(errp, "Error creating migration incoming channel"); > > + } > > } > > diff --git a/migration/migration.c b/migration/migration.c > > index 16da269847..e2218b9de7 100644 > > --- a/migration/migration.c > > +++ b/migration/migration.c > > @@ -896,7 +896,8 @@ void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp) > > uint32_t channel_magic = 0; > > int ret = 0; > > > > - if (migrate_multifd() && !migrate_postcopy_ram() && > > + if (migrate_multifd() && !migrate_fixed_ram() && > > + !migrate_postcopy_ram() && > > qio_channel_has_feature(ioc, QIO_CHANNEL_FEATURE_READ_MSG_PEEK)) { > > /* > > * With multiple channels, it is possible that we receive channels > > diff --git a/migration/multifd.c b/migration/multifd.c > > index 507b497d52..cb5f4fb3e0 100644 > > --- a/migration/multifd.c > > +++ b/migration/multifd.c > > @@ -1520,8 +1520,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error **errp) > > } > > trace_multifd_recv_new_channel(id); > > } else { > > - /* next patch gives this a meaningful value */ > > - id = 0; > > + id = qatomic_read(&multifd_recv_state->count); > > } > > > > p = &multifd_recv_state->params[id]; > > -- > > 2.35.3 > > > > -- > Peter Xu -- Peter Xu