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=-17.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 4D3C9C43214 for ; Mon, 30 Aug 2021 20:46:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E95760ED6 for ; Mon, 30 Aug 2021 20:46:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236559AbhH3UrO (ORCPT ); Mon, 30 Aug 2021 16:47:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229708AbhH3UrN (ORCPT ); Mon, 30 Aug 2021 16:47:13 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D448C061575 for ; Mon, 30 Aug 2021 13:46:19 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 03DE47C6E; Mon, 30 Aug 2021 16:46:17 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 03DE47C6E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1630356377; bh=hSWmsE9lWy3Caf3Go57RMX6C4UpWZoY3uqe0f5zg/VA=; h=Date:To:Cc:Subject:References:In-Reply-To:From:From; b=ei2R29RoFob25X8lvwas0u7kfnRf7x5zPmCpiQDsd23LUItsTcJT9L26d8n2uKLQ8 SQ0bpnBLDCzGRqI6Um9hioTJkyZy5qsg1oStZSvEkm0i6efNyZuu0UIviwgath0vzv FeB6Gpdj2f3A0c5n35stUfwgLb+r0rXPFDDw1/2E= Date: Mon, 30 Aug 2021 16:46:16 -0400 To: NeilBrown Cc: Chuck Lever III , Mike Javorski , Mel Gorman , Linux NFS Mailing List Subject: Re: [PATCH] SUNRPC: don't pause on incomplete allocation Message-ID: <20210830204616.GA13399@fieldses.org> References: <163004202961.7591.12633163545286005205@noble.neil.brown.name> <163004848514.7591.2757618782251492498@noble.neil.brown.name> <6CC9C852-CEE3-4657-86AD-9D5759E2BE1C@oracle.com> <416268C9-BEAC-483C-9392-8139340BC849@oracle.com> <12B831AA-4A4E-4102-ADA3-97B6FA0B119E@oracle.com> <163027659478.7591.8897815399981483759@noble.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <163027659478.7591.8897815399981483759@noble.neil.brown.name> User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org For what it's worth, another positive report on this patch: https://bugzilla.kernel.org/show_bug.cgi?id=213869#c10 --b. On Mon, Aug 30, 2021 at 08:36:34AM +1000, NeilBrown wrote: > > alloc_pages_bulk_array() attempts to allocate at least one page based on > the provided pages, and then opportunistically allocates more if that > can be done without dropping the spinlock. > > So if it returns fewer than requested, that could just mean that it > needed to drop the lock. In that case, try again immediately. > > Only pause for a time if no progress could be made. > > Reported-and-tested-by: Mike Javorski > Reported-and-tested-by: Lothar Paltins > Fixes: f6e70aab9dfe ("SUNRPC: refresh rq_pages using a bulk page allocator") > Signed-off-by: NeilBrown > --- > > I decided I would resend, as I thought the for() loops could be clearer. > This patch should perform exactly the same as the previous one. > > > net/sunrpc/svc_xprt.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c > index d66a8e44a1ae..e74d5cf3cbb4 100644 > --- a/net/sunrpc/svc_xprt.c > +++ b/net/sunrpc/svc_xprt.c > @@ -662,7 +662,7 @@ static int svc_alloc_arg(struct svc_rqst *rqstp) > { > struct svc_serv *serv = rqstp->rq_server; > struct xdr_buf *arg = &rqstp->rq_arg; > - unsigned long pages, filled; > + unsigned long pages, filled, ret; > > pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT; > if (pages > RPCSVC_MAXPAGES) { > @@ -672,11 +672,12 @@ static int svc_alloc_arg(struct svc_rqst *rqstp) > pages = RPCSVC_MAXPAGES; > } > > - for (;;) { > - filled = alloc_pages_bulk_array(GFP_KERNEL, pages, > - rqstp->rq_pages); > - if (filled == pages) > - break; > + for (filled = 0; filled < pages; filled = ret) { > + ret = alloc_pages_bulk_array(GFP_KERNEL, pages, > + rqstp->rq_pages); > + if (ret > filled) > + /* Made progress, don't sleep yet */ > + continue; > > set_current_state(TASK_INTERRUPTIBLE); > if (signalled() || kthread_should_stop()) { > -- > 2.32.0