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 us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 8E4C8C433EF for ; Mon, 29 Nov 2021 20:29:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638217771; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=e0wzt/bfgQNUO11msJqbzCJvTnRWxgswCyai7Ii2PXY=; b=Cs7OeIyKO/BPaEhhBjBz0zOd6EvWjnziFX8KuGWZA3xpuWm5xNapUjpmp91LiaPB5/ju+j bM19wGtlbK2Osjt9i++9lQKKXAz1LYqJfT29FEiALnVc9Y5UBSZD53uRaDyqkAXXwI1kcD LBVMAYLTbltf/LXoSA94yoNeNiyo/OY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-333-a8XV-qS8Nc6YMwiIAwz63g-1; Mon, 29 Nov 2021 15:29:27 -0500 X-MC-Unique: a8XV-qS8Nc6YMwiIAwz63g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 592FB1006AA4; Mon, 29 Nov 2021 20:29:23 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F37A419729; Mon, 29 Nov 2021 20:29:22 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 0459B4A700; Mon, 29 Nov 2021 20:29:21 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 1ATKTKH9003649 for ; Mon, 29 Nov 2021 15:29:20 -0500 Received: by smtp.corp.redhat.com (Postfix) id 92B5610114AE; Mon, 29 Nov 2021 20:29:20 +0000 (UTC) Received: from octiron.msp.redhat.com (unknown [10.15.80.209]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 59F44100EBAD; Mon, 29 Nov 2021 20:29:11 +0000 (UTC) Received: from octiron.msp.redhat.com (localhost.localdomain [127.0.0.1]) by octiron.msp.redhat.com (8.14.9/8.14.9) with ESMTP id 1ATKT96L022395; Mon, 29 Nov 2021 14:29:09 -0600 Received: (from bmarzins@localhost) by octiron.msp.redhat.com (8.14.9/8.14.9/Submit) id 1ATKT9Jt022394; Mon, 29 Nov 2021 14:29:09 -0600 Date: Mon, 29 Nov 2021 14:29:08 -0600 From: Benjamin Marzinski To: mwilck@suse.com Message-ID: <20211129202908.GF19591@octiron.msp.redhat.com> References: <20211127151929.7727-1-mwilck@suse.com> <20211127151929.7727-34-mwilck@suse.com> MIME-Version: 1.0 In-Reply-To: <20211127151929.7727-34-mwilck@suse.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-loop: dm-devel@redhat.com Cc: lixiaokeng@huawei.com, dm-devel@redhat.com, Chongyun Wu Subject: Re: [dm-devel] [PATCH v3 32/35] multipathd: uxlsnr: use poll loop for sending, too X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Sat, Nov 27, 2021 at 04:19:26PM +0100, mwilck@suse.com wrote: > From: Martin Wilck > > send_packet() may busy-loop. By polling for POLLOUT, we can > avoid that, even if it's very unlikely in practice. > > Signed-off-by: Martin Wilck Reviewed-by: Benjamin Marzinski > --- > multipathd/uxlsnr.c | 41 ++++++++++++++++++++++++++++++----------- > 1 file changed, 30 insertions(+), 11 deletions(-) > > diff --git a/multipathd/uxlsnr.c b/multipathd/uxlsnr.c > index 1ebcf10..c5da569 100644 > --- a/multipathd/uxlsnr.c > +++ b/multipathd/uxlsnr.c > @@ -447,7 +447,6 @@ static int client_state_machine(struct client *c, struct vectors *vecs, > short revents) > { > ssize_t n; > - const char *buf; > > condlog(4, "%s: cli[%d] poll=%x state=%d cmd=\"%s\" repl \"%s\"", __func__, > c->fd, revents, c->state, c->cmd, get_strbuf_str(&c->reply)); > @@ -527,7 +526,8 @@ static int client_state_machine(struct client *c, struct vectors *vecs, > free_keys(c->cmdvec); > c->cmdvec = NULL; > set_client_state(c, CLT_SEND); > - return STM_CONT; > + /* Wait for POLLOUT */ > + return STM_BREAK; > } else { > condlog(4, "%s: cli[%d] waiting for lock", __func__, c->fd); > return STM_BREAK; > @@ -538,22 +538,38 @@ static int client_state_machine(struct client *c, struct vectors *vecs, > free_keys(c->cmdvec); > c->cmdvec = NULL; > set_client_state(c, CLT_SEND); > - return STM_CONT; > + /* Wait for POLLOUT */ > + return STM_BREAK; > > case CLT_SEND: > if (get_strbuf_len(&c->reply) == 0) > default_reply(c, c->error); > > - buf = get_strbuf_str(&c->reply); > + if (c->cmd_len == 0) { > + size_t len = get_strbuf_len(&c->reply) + 1; > > - if (send_packet(c->fd, buf) != 0) > - dead_client(c); > - else > - condlog(4, "cli[%d]: Reply [%zu bytes]", c->fd, > - get_strbuf_len(&c->reply) + 1); > - reset_strbuf(&c->reply); > + if (send(c->fd, &len, sizeof(len), MSG_NOSIGNAL) > + != sizeof(len)) > + c->error = -ECONNRESET; > + c->cmd_len = len; > + return STM_BREAK; > + } > > - set_client_state(c, CLT_RECV); > + if (c->len < c->cmd_len) { > + const char *buf = get_strbuf_str(&c->reply); > + > + n = send(c->fd, buf + c->len, c->cmd_len, MSG_NOSIGNAL); > + if (n == -1) { > + if (!(errno == EAGAIN || errno == EINTR)) > + c->error = -ECONNRESET; > + } else > + c->len += n; > + } > + > + if (c->len >= c->cmd_len) { > + condlog(4, "cli[%d]: Reply [%zu bytes]", c->fd, c->cmd_len); > + set_client_state(c, CLT_RECV); > + } > return STM_BREAK; > > default: > @@ -687,6 +703,9 @@ void *uxsock_listen(long ux_sock, void *trigger_data) > case CLT_RECV: > polls[i].events = POLLIN; > break; > + case CLT_SEND: > + polls[i].events = POLLOUT; > + break; > default: > /* don't poll for this client */ > continue; > -- > 2.33.1 -- dm-devel mailing list dm-devel@redhat.com https://listman.redhat.com/mailman/listinfo/dm-devel