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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1373AC433EF for ; Mon, 4 Oct 2021 14:56:45 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 7392261029 for ; Mon, 4 Oct 2021 14:56:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7392261029 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:39822 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXPOV-00020B-LP for qemu-devel@archiver.kernel.org; Mon, 04 Oct 2021 10:56:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57840) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXPMg-0000bN-57 for qemu-devel@nongnu.org; Mon, 04 Oct 2021 10:54:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:51123) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXPMe-0005wD-Du for qemu-devel@nongnu.org; Mon, 04 Oct 2021 10:54:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633359287; 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=gXCadVxY5s3oUF7aLJbkP2tSSY3h2TvKcXoHow6YzXo=; b=bFSWP6h5x4q0qHxfWQ6hbR2N5BXZ4vm26kX4Vo1ICU1oQVu5Ub7vEhQCxRFgV05BKGmvNk Rh8+od412cLjsh3v8vhCK2jZ7jNRMFChS8+un+qnOOPMDxn5UU62Sq+WePfrUV5z8SD7zx 20qkmbsCKC9Nqzmd7u+0VSPf6EfLXKc= 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-556-ENvexLuJO8ytwxn64WJG8w-1; Mon, 04 Oct 2021 10:54:46 -0400 X-MC-Unique: ENvexLuJO8ytwxn64WJG8w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 709F8DF8AD; Mon, 4 Oct 2021 14:54:45 +0000 (UTC) Received: from localhost (unknown [10.39.194.243]) by smtp.corp.redhat.com (Postfix) with ESMTP id 05CB460843; Mon, 4 Oct 2021 14:54:32 +0000 (UTC) Date: Mon, 4 Oct 2021 15:54:31 +0100 From: Stefan Hajnoczi To: Vivek Goyal Subject: Re: [PATCH 10/13] virtiofsd: Custom threadpool for remote blocking posix locks requests Message-ID: References: <20210930153037.1194279-1-vgoyal@redhat.com> <20210930153037.1194279-11-vgoyal@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210930153037.1194279-11-vgoyal@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Z+FomQ254OgZIFhd" Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: miklos@szeredi.hu, qemu-devel@nongnu.org, iangelak@redhat.com, dgilbert@redhat.com, virtio-fs@redhat.com, jaggel@bu.edu Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" --Z+FomQ254OgZIFhd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 30, 2021 at 11:30:34AM -0400, Vivek Goyal wrote: > Add a new custom threadpool using posix threads that specifically > service locking requests. >=20 > In the case of a fcntl(SETLKW) request, if the guest is waiting > for a lock or locks and issues a hard-reboot through SYSRQ then virtiofsd > unblocks the blocked threads by sending a signal to them and waking > them up. >=20 > The current threadpool (GThreadPool) is not adequate to service the > locking requests that result in a thread blocking. That is because > GLib does not provide an API to cancel the request while it is > serviced by a thread. In addition, a user might be running virtiofsd > without a threadpool (--thread-pool-size=3D0), thus a locking request > that blocks, will block the main virtqueue thread that services requests > from servicing any other requests. >=20 > The only exception occurs when the lock is of type F_UNLCK. In this case > the request is serviced by the main virtqueue thread or a GThreadPool > thread to avoid a deadlock, when all the threads in the custom threadpool > are blocked. >=20 > Then virtiofsd proceeds to cleanup the state of the threads, release > them back to the system and re-initialize. Is there another way to cancel SETLKW without resorting to a new thread pool? Since this only matters when shutting down or restarting, can we close all plock->fd file descriptors to kick the GThreadPool workers out of fnctl()? >=20 > Signed-off-by: Ioannis Angelakopoulos > Signed-off-by: Vivek Goyal > --- > tools/virtiofsd/fuse_virtio.c | 90 ++++++- > tools/virtiofsd/meson.build | 1 + > tools/virtiofsd/passthrough_seccomp.c | 1 + > tools/virtiofsd/tpool.c | 331 ++++++++++++++++++++++++++ > tools/virtiofsd/tpool.h | 18 ++ > 5 files changed, 440 insertions(+), 1 deletion(-) > create mode 100644 tools/virtiofsd/tpool.c > create mode 100644 tools/virtiofsd/tpool.h >=20 > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.= c > index 3b720c5d4a..c67c2e0e7a 100644 > --- a/tools/virtiofsd/fuse_virtio.c > +++ b/tools/virtiofsd/fuse_virtio.c > @@ -20,6 +20,7 @@ > #include "fuse_misc.h" > #include "fuse_opt.h" > #include "fuse_virtio.h" > +#include "tpool.h" > =20 > #include > #include > @@ -612,6 +613,60 @@ out: > free(req); > } > =20 > +/* > + * If the request is a locking request, use a custom locking thread pool= . > + */ > +static bool use_lock_tpool(gpointer data, gpointer user_data) > +{ > + struct fv_QueueInfo *qi =3D user_data; > + struct fuse_session *se =3D qi->virtio_dev->se; > + FVRequest *req =3D data; > + VuVirtqElement *elem =3D &req->elem; > + struct fuse_buf fbuf =3D {}; > + struct fuse_in_header *inhp; > + struct fuse_lk_in *lkinp; > + size_t lk_req_len; > + /* The 'out' part of the elem is from qemu */ > + unsigned int out_num =3D elem->out_num; > + struct iovec *out_sg =3D elem->out_sg; > + size_t out_len =3D iov_size(out_sg, out_num); > + bool use_custom_tpool =3D false; > + > + /* > + * If notifications are not enabled, no point in using cusotm lock > + * thread pool. > + */ > + if (!se->notify_enabled) { > + return false; > + } > + > + assert(se->bufsize > sizeof(struct fuse_in_header)); > + lk_req_len =3D sizeof(struct fuse_in_header) + sizeof(struct fuse_lk= _in); > + > + if (out_len < lk_req_len) { > + return false; > + } > + > + fbuf.mem =3D g_malloc(se->bufsize); > + copy_from_iov(&fbuf, out_num, out_sg, lk_req_len); This looks inefficient: for every FUSE request we now malloc se->bufsize and then copy lk_req_len bytes, only to free the memory again. Is it possible to keep lk_req_len bytes on the stack instead? --Z+FomQ254OgZIFhd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmFbFacACgkQnKSrs4Gr c8gBBgf/SjkAY3cbcX+VAOrCSPviGcgx7hxVc6MFQDC3AqygPX/X/MAHncPoXxYq ug/wH6P/4ls/Fzf06KX0EwaWKlTr9+HdGA1nYbGXmxEJ5BsYhPcj/ipGuiGDEcap BKVxyD/Qtd1sCaqYR0P3AGua22wYIhrD3O9RUINrDoL9MdWB5aIhThnabQ2/6NFO S6UL3EaknNQAT8mpdgTcnWPVqrCcNWHCjdfxPO8QL/6Be5LAYJzLKWJkX6AIEnv1 JEM/T3jT2GijYHPBBMLl3qV3CCARdOBkM+OFf7xWr5YlD003n5rSUovuTRV7mcBf LrhCsPN3vd5wpuz949rAlc5zH7x8qg== =2V8P -----END PGP SIGNATURE----- --Z+FomQ254OgZIFhd-- From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 4 Oct 2021 15:54:31 +0100 From: Stefan Hajnoczi Message-ID: References: <20210930153037.1194279-1-vgoyal@redhat.com> <20210930153037.1194279-11-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Z+FomQ254OgZIFhd" Content-Disposition: inline In-Reply-To: <20210930153037.1194279-11-vgoyal@redhat.com> Subject: Re: [Virtio-fs] [PATCH 10/13] virtiofsd: Custom threadpool for remote blocking posix locks requests List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vivek Goyal Cc: miklos@szeredi.hu, qemu-devel@nongnu.org, virtio-fs@redhat.com --Z+FomQ254OgZIFhd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 30, 2021 at 11:30:34AM -0400, Vivek Goyal wrote: > Add a new custom threadpool using posix threads that specifically > service locking requests. >=20 > In the case of a fcntl(SETLKW) request, if the guest is waiting > for a lock or locks and issues a hard-reboot through SYSRQ then virtiofsd > unblocks the blocked threads by sending a signal to them and waking > them up. >=20 > The current threadpool (GThreadPool) is not adequate to service the > locking requests that result in a thread blocking. That is because > GLib does not provide an API to cancel the request while it is > serviced by a thread. In addition, a user might be running virtiofsd > without a threadpool (--thread-pool-size=3D0), thus a locking request > that blocks, will block the main virtqueue thread that services requests > from servicing any other requests. >=20 > The only exception occurs when the lock is of type F_UNLCK. In this case > the request is serviced by the main virtqueue thread or a GThreadPool > thread to avoid a deadlock, when all the threads in the custom threadpool > are blocked. >=20 > Then virtiofsd proceeds to cleanup the state of the threads, release > them back to the system and re-initialize. Is there another way to cancel SETLKW without resorting to a new thread pool? Since this only matters when shutting down or restarting, can we close all plock->fd file descriptors to kick the GThreadPool workers out of fnctl()? >=20 > Signed-off-by: Ioannis Angelakopoulos > Signed-off-by: Vivek Goyal > --- > tools/virtiofsd/fuse_virtio.c | 90 ++++++- > tools/virtiofsd/meson.build | 1 + > tools/virtiofsd/passthrough_seccomp.c | 1 + > tools/virtiofsd/tpool.c | 331 ++++++++++++++++++++++++++ > tools/virtiofsd/tpool.h | 18 ++ > 5 files changed, 440 insertions(+), 1 deletion(-) > create mode 100644 tools/virtiofsd/tpool.c > create mode 100644 tools/virtiofsd/tpool.h >=20 > diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c > index 3b720c5d4a..c67c2e0e7a 100644 > --- a/tools/virtiofsd/fuse_virtio.c > +++ b/tools/virtiofsd/fuse_virtio.c > @@ -20,6 +20,7 @@ > #include "fuse_misc.h" > #include "fuse_opt.h" > #include "fuse_virtio.h" > +#include "tpool.h" > =20 > #include > #include > @@ -612,6 +613,60 @@ out: > free(req); > } > =20 > +/* > + * If the request is a locking request, use a custom locking thread pool. > + */ > +static bool use_lock_tpool(gpointer data, gpointer user_data) > +{ > + struct fv_QueueInfo *qi =3D user_data; > + struct fuse_session *se =3D qi->virtio_dev->se; > + FVRequest *req =3D data; > + VuVirtqElement *elem =3D &req->elem; > + struct fuse_buf fbuf =3D {}; > + struct fuse_in_header *inhp; > + struct fuse_lk_in *lkinp; > + size_t lk_req_len; > + /* The 'out' part of the elem is from qemu */ > + unsigned int out_num =3D elem->out_num; > + struct iovec *out_sg =3D elem->out_sg; > + size_t out_len =3D iov_size(out_sg, out_num); > + bool use_custom_tpool =3D false; > + > + /* > + * If notifications are not enabled, no point in using cusotm lock > + * thread pool. > + */ > + if (!se->notify_enabled) { > + return false; > + } > + > + assert(se->bufsize > sizeof(struct fuse_in_header)); > + lk_req_len =3D sizeof(struct fuse_in_header) + sizeof(struct fuse_lk= _in); > + > + if (out_len < lk_req_len) { > + return false; > + } > + > + fbuf.mem =3D g_malloc(se->bufsize); > + copy_from_iov(&fbuf, out_num, out_sg, lk_req_len); This looks inefficient: for every FUSE request we now malloc se->bufsize and then copy lk_req_len bytes, only to free the memory again. Is it possible to keep lk_req_len bytes on the stack instead? --Z+FomQ254OgZIFhd Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmFbFacACgkQnKSrs4Gr c8gBBgf/SjkAY3cbcX+VAOrCSPviGcgx7hxVc6MFQDC3AqygPX/X/MAHncPoXxYq ug/wH6P/4ls/Fzf06KX0EwaWKlTr9+HdGA1nYbGXmxEJ5BsYhPcj/ipGuiGDEcap BKVxyD/Qtd1sCaqYR0P3AGua22wYIhrD3O9RUINrDoL9MdWB5aIhThnabQ2/6NFO S6UL3EaknNQAT8mpdgTcnWPVqrCcNWHCjdfxPO8QL/6Be5LAYJzLKWJkX6AIEnv1 JEM/T3jT2GijYHPBBMLl3qV3CCARdOBkM+OFf7xWr5YlD003n5rSUovuTRV7mcBf LrhCsPN3vd5wpuz949rAlc5zH7x8qg== =2V8P -----END PGP SIGNATURE----- --Z+FomQ254OgZIFhd--