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Mon, 20 Dec 2021 12:16:41 +0000 (UTC) X-FDA: 78938071002.02.E446FDE Received: from mail-ua1-f41.google.com (mail-ua1-f41.google.com [209.85.222.41]) by imf22.hostedemail.com (Postfix) with ESMTP id 923F8C003D for ; Mon, 20 Dec 2021 12:16:40 +0000 (UTC) Received: by mail-ua1-f41.google.com with SMTP id y23so17242303uay.7 for ; Mon, 20 Dec 2021 04:16:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BnyBbvTY2/pKI2NR4Gal0C7RZeDcNiAJl2jICNilH6I=; b=Bt6YGTCXwGNAvirMEQP0AHRNRy/2/wJsw+vCNB9m5TwvJprBiSnybgi+QyPQah7jC6 EV13TvSBJIHYQA4igync1RezOtGeAZwejzeXIMoPrGjRmQuRVndHAd5A3H9f/FKLfcak MVDrVusk5HGLpsyQd4fWmGP131p0MMewzuOmWFTcjyA4eBxaWdYDoUAV7pDx4Q8ZfKhj qkG312tYJuvuO7yzXFQBQ7sz1Yx8uZAWBtnn/H/kSzcf8hn/bVYgCpKmnE9Y4ud2aFCD hkdHWNgYWIfCc+YTxqezEUkDymtk7sLoGEAUrQ8SbnbWww1+o4jxXvDrIXkrjdn98Wtl CJ2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BnyBbvTY2/pKI2NR4Gal0C7RZeDcNiAJl2jICNilH6I=; b=3oYBlgHTV3YHkhiStwLBYPhYNk+ju5SrRBDGffCLniKua/seTuM/av4zKRQ5rMTGBi FYf1pSyYU8XyHpr5nx+r7R8e7XLXnLGOCpQE8ldQipbWDcmjC8Grw93TCWuzZ8ST7oJe /32Dxp45bQuwSF+AtoJbbismDUca9RgAZaa+9fQtIjnv/Bs70Yjxi0rPbSMrCjS0islu WyMTFG/EfdHcKJ5qpTTI/ielJWsIg97j94Dvz+FMutKaRumN/EEsbq5H/N3WT0jj6swt TpZyoWhGgiXj+Ni8+HBLcDlblOx2nR0rPaD5cfP5T1FxQA+ZD0TtwuJL1VfSFvoGH/ll Bydw== X-Gm-Message-State: AOAM5313Law7Aognudpe8+MUOphviWomDIpOs10ibnFi+OARYDf5JPiq RPcdv3pj8IN08xAfPLJLVJYCYM6LxRmCAxUXEIc= X-Google-Smtp-Source: ABdhPJyWy6U0BNJoQtTswaImkgCV1g1YpfkFneizSDMyZR6deqY5q9HDiX+0l0BAJ8fr4qzA9Ca5F2oXXh1jejM02BM= X-Received: by 2002:a9f:35ad:: with SMTP id t42mr4912618uad.105.1640002600402; Mon, 20 Dec 2021 04:16:40 -0800 (PST) MIME-Version: 1.0 References: <163969801519.20885.3977673503103544412.stgit@noble.brown> <163969850289.20885.1044395970457169316.stgit@noble.brown> In-Reply-To: <163969850289.20885.1044395970457169316.stgit@noble.brown> From: Mark Hemment Date: Mon, 20 Dec 2021 12:16:29 +0000 Message-ID: Subject: Re: [PATCH 03/18] MM: use ->swap_rw for reads from SWP_FS_OPS swap-space To: NeilBrown Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , Andrew Morton , Mel Gorman , Christoph Hellwig , David Howells , linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 923F8C003D X-Stat-Signature: zcz38ft5qdyscgqz7n6gmkqpqg93xybh Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=googlemail.com header.s=20210112 header.b=Bt6YGTCX; dmarc=pass (policy=quarantine) header.from=googlemail.com; spf=pass (imf22.hostedemail.com: domain of markhemm@googlemail.com designates 209.85.222.41 as permitted sender) smtp.mailfrom=markhemm@googlemail.com X-Rspamd-Server: rspam11 X-HE-Tag: 1640002600-63487 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 16 Dec 2021 at 23:54, NeilBrown wrote: > > To submit an async read with ->swap_rw() we need to allocate > a structure to hold the kiocb and other details. swap_readpage() cannot > handle transient failure, so create a mempool to provide the structures. > > Signed-off-by: NeilBrown > --- > mm/page_io.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++------ > mm/swap.h | 1 + > mm/swapfile.c | 5 +++++ > 3 files changed, 58 insertions(+), 6 deletions(-) ... > diff --git a/mm/swapfile.c b/mm/swapfile.c > index f23d9ff21cf8..43539be38e68 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -2401,6 +2401,11 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) > if (ret < 0) > return ret; > sis->flags |= SWP_ACTIVATED; > + if ((sis->flags & SWP_FS_OPS) && > + sio_pool_init() != 0) { > + destroy_swap_extents(sis); > + return -ENOMEM; > + } > return ret; > } This code is called before 'swapon_mutex' is taken in the swapon code path, so possible for multiple swapons to race here creating two (or more) memory pools. Mark