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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 7FD9AC2D0A8 for ; Mon, 28 Sep 2020 13:59:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 424AF21D46 for ; Mon, 28 Sep 2020 13:59:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601301573; bh=D+I3v74T0NzTkTKP8jBGG82AJhHbHC+4HvW1CTgJUDA=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=ywBmVCW8ojb3pMZoi2p/LvwXgq115VJnhREaXLKznsjnNO2RWBcUDwUrlL1rC4uqm jkPSjpy6GB+nWWCxHhGMK2QQkR4VVyZ2yY5KycKtAvmEdfNf813ZlCKMNJBw80rQXE 8pFYugrE78txcHl4cwImQsq4DCVRxbsSpH55sZDI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726348AbgI1N7c (ORCPT ); Mon, 28 Sep 2020 09:59:32 -0400 Received: from mail-oo1-f65.google.com ([209.85.161.65]:33380 "EHLO mail-oo1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726327AbgI1N7c (ORCPT ); Mon, 28 Sep 2020 09:59:32 -0400 Received: by mail-oo1-f65.google.com with SMTP id m25so330110oou.0 for ; Mon, 28 Sep 2020 06:59:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=f3P4p+l5MhY0I6i7/hzENLpXbDC1mSdW78+Xm6+lNHg=; b=IFs2s3csLHSXsp1BdOycGORVkOa8LA5LB/OiaKntHbXA13BvOM5bBrXbPQsigYAGxJ iOieiZKmuzrHW0OAd9IxNwfvXZ5YgEmk18vXJRMyoJKRo8ZwdAbPPZSPve9Sr86r36an KvXOIjb0MLPyQOcxgvYI5mWLfJ5LmMU3q7MsHc9xngaUylv7zH4qOUNBfZcVvOGEy+Eb PtPTOlzxkh/yDhJvjHo8IHusJrEJNbT7YlueBgIWytBhmmdXBTXtwchpje4dXO3+zW8k e4YzSl5Piu/QLsBCXvjZC2mTBCndv5eKDVRKqFOSORJY7wGDWuf4u3Jdwz9AryOyxZj0 hMdA== X-Gm-Message-State: AOAM532+IkymQGNDq9bnF6oN/D78n1Yjl2sJ5+yrcjw5FLCLV12O+v9H hSNbdmuPVR+qkkQl6ZT6PoYNR4KPdBB5/2oBWBnGmk6W X-Google-Smtp-Source: ABdhPJz56SqTdP4ZY9s/UTpwTIPddv65CKTA0c5/QYc99ATVCayVHldEF6+ksF47hc1UdYBsPv0EaDA+PgAsUuQItTg= X-Received: by 2002:a4a:dd0b:: with SMTP id m11mr914703oou.75.1601301571609; Mon, 28 Sep 2020 06:59:31 -0700 (PDT) MIME-Version: 1.0 References: <667ded38-06a6-d058-ca22-a53eed384fd4@amazon.com> In-Reply-To: <667ded38-06a6-d058-ca22-a53eed384fd4@amazon.com> From: "Rafael J. Wysocki" Date: Mon, 28 Sep 2020 15:59:15 +0200 Message-ID: Subject: Re: [PATCH] PM: Batch hibernate and resume IO requests To: "Chen, Xiaoyi" Cc: "Rafael J. Wysocki" , Pavel Machek , "linux-pm@vger.kernel.org" , "Agarwal, Anchal" , "Duncan, David" , Dave Chinner , Eric Sandeen Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, Sep 25, 2020 at 9:26 PM Chen, Xiaoyi wrote: > > On 9/25/20 4:27 PM, Rafael J. Wysocki wrote: > > > > > > On Tue, Sep 22, 2020 at 6:19 PM Chen, Xiaoyi wrote: > >> > >> > >> Hibernate and resume process submits individual IO requests for each page > >> of the data. With this patch, we use blk_plug to improve the batching of > >> these requests. > >> > >> Tested this patch with hibernate and resumes, and consistently observed the > >> merging of the IO requests. We see more than an order of magnitude > >> improvement in hibernate and resume speed. > >> > >> One hibernate and resume cycle for 16GB used RAM out of 32GB takes around > >> 21 minutes before the change, and 1 minutes after the change on systems > >> with limited storage IOPS. > >> > >> Signed-off-by: Xiaoyi Chen > >> Signed-off-by: Anchal Agarwal > >> --- > >> kernel/power/swap.c | 15 +++++++++++++++ > >> 1 file changed, 15 insertions(+) > >> > >> diff --git a/kernel/power/swap.c b/kernel/power/swap.c > >> index 01e2858b5fe3..961615365b5c 100644 > >> --- a/kernel/power/swap.c > >> +++ b/kernel/power/swap.c > >> @@ -226,6 +226,7 @@ struct hib_bio_batch { > >> atomic_t count; > >> wait_queue_head_t wait; > >> blk_status_t error; > >> + struct blk_plug plug; > >> }; > >> > >> static void hib_init_batch(struct hib_bio_batch *hb) > >> @@ -233,6 +234,12 @@ static void hib_init_batch(struct hib_bio_batch *hb) > >> atomic_set(&hb->count, 0); > >> init_waitqueue_head(&hb->wait); > >> hb->error = BLK_STS_OK; > >> + blk_start_plug(&hb->plug); > >> +} > >> + > >> +static void hib_finish_batch(struct hib_bio_batch *hb) > >> +{ > >> + blk_finish_plug(&hb->plug); > >> } > >> > >> static void hib_end_io(struct bio *bio) > >> @@ -294,6 +301,10 @@ static int hib_submit_io(int op, int op_flags, pgoff_t page_off, void *addr, > >> > >> static blk_status_t hib_wait_io(struct hib_bio_batch *hb) > >> { > >> + /* > >> + * We are relying on the behavior of blk_plug that a thread with > >> + * a plug will flush the plug list before sleeping. > >> + */ > >> wait_event(hb->wait, atomic_read(&hb->count) == 0); > >> return blk_status_to_errno(hb->error); > >> } > >> @@ -561,6 +572,7 @@ static int save_image(struct swap_map_handle *handle, > >> nr_pages++; > >> } > >> err2 = hib_wait_io(&hb); > >> + hib_finish_batch(&hb); > >> stop = ktime_get(); > >> if (!ret) > >> ret = err2; > >> @@ -854,6 +866,7 @@ static int save_image_lzo(struct swap_map_handle *handle, > >> pr_info("Image saving done\n"); > >> swsusp_show_speed(start, stop, nr_to_write, "Wrote"); > >> out_clean: > >> + hib_finish_batch(&hb); > >> if (crc) { > >> if (crc->thr) > >> kthread_stop(crc->thr); > >> @@ -1084,6 +1097,7 @@ static int load_image(struct swap_map_handle *handle, > >> nr_pages++; > >> } > >> err2 = hib_wait_io(&hb); > >> + hib_finish_batch(&hb); > >> stop = ktime_get(); > >> if (!ret) > >> ret = err2; > >> @@ -1447,6 +1461,7 @@ static int load_image_lzo(struct swap_map_handle *handle, > >> } > >> swsusp_show_speed(start, stop, nr_to_read, "Read"); > >> out_clean: > >> + hib_finish_batch(&hb); > >> for (i = 0; i < ring_size; i++) > >> free_page((unsigned long)page[i]); > >> if (crc) { > >> -- > > > > Applied as 5.10 material with some subject and changelog edits, but: > > 1. The patch is white-space-damaged and I needed to fix that up > > manually which was not fun. > > 2. I dropped the second S-o-b, because it was not clear to me whether > > a Co-developed-by tag was missing or Reviewed-by should have been used > > instead. > > > > Thanks! > > > > Thanks for the prompt review. Apologies for the white-space and tags > issues, will do better next time. > > Would you mind adding following tags if not too late? > Signed-off-by: Anchal Agarwal > Co-Developed-by: Anchal Agarwal Done, thanks!