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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FA77C433FE for ; Fri, 29 Apr 2022 19:04:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F142F6B0071; Fri, 29 Apr 2022 15:04:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EC3336B0072; Fri, 29 Apr 2022 15:04:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D63E96B0073; Fri, 29 Apr 2022 15:04:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id C6DCE6B0071 for ; Fri, 29 Apr 2022 15:04:55 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id 63EB2120989 for ; Fri, 29 Apr 2022 19:04:55 +0000 (UTC) X-FDA: 79410843750.18.170B797 Received: from mail-pf1-f177.google.com (mail-pf1-f177.google.com [209.85.210.177]) by imf25.hostedemail.com (Postfix) with ESMTP id 6C5F4A0024 for ; Fri, 29 Apr 2022 19:04:45 +0000 (UTC) Received: by mail-pf1-f177.google.com with SMTP id bo5so7682283pfb.4 for ; Fri, 29 Apr 2022 12:04:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=QqxV8SgMeflDFmUbpjCjuBhww/TZdT/CeB66xbgfc7I=; b=Ojqvo3+w49gK8bzrBn89rOirlJzB4XuOAzcvQE5X6EsnGCJjqU3roOlPbgOvRw89hv spfJSNlSX+v3RKSjOrgXqUE8XqXiTkoHjSVzzp7TcLEfCwl8RrUdUyVMsQC5/2JaLUVg 80UtWArbAdFZS3n/C7UwVwFj8RPhbTDrmVO16NUytVd8CaaW1ZHVRxF7rOEGocS/Etsp wOsgzcevrzU52oBLgIkvMkg29X6agXinxkypUn78dT9yaquMGpglyJwAUMUZomiCNbWM RU4hC6PRL3kSRwYLpIqw8kyTkU2Do3X1NucJm5mdURivK2KqXjP2CJj/37KC4Nviqkf3 zdIA== 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=QqxV8SgMeflDFmUbpjCjuBhww/TZdT/CeB66xbgfc7I=; b=BRlhRwejVCeaDSCWLJ77rv3X4ofAiVVJuD8AVTU7aGd2YGSe7mUkeAscsVTdFRP3DN wUaGuUOIFv++uTAjGOxHsVD+PfpDqwvqBimECnNLg9+c1xeP1D5H6H1PnmOaNP4GUVmu OU6CdXkVODO09xA6dZc6BskohRhnk2smxntC8dOhCpCW0T4boiKiutEI3/eH32rmkYsT CeV3wPNkk//wiIG81jAgFa4n9k6dUbyIF0FnTp0RvnTN7a8ioI0xMb3d4+yBnuCVExuz mhxdtaJi5JkWENez49jC+pBayyN4LC7Ymv65Mpq7gZK+zgkSD3uXWemtM8VhViYMymq0 /Jqg== X-Gm-Message-State: AOAM5321K4vwRYHJOGvaGstKKdbyGelP1wnSV6Lj/sg4imEuTyGaSIfr V8vRhyQ6Eqp8JymIVluveP4GWpJ+aMGcnsZnzoWMs3rV X-Google-Smtp-Source: ABdhPJyXzQ9yOioq4oKJTYFlGewE09wdvTMBKSEK4Sf1gAiuTyvytPFlYMMoLxH4EC6sRAL0ke9HTmrgHXPJTI0trn8= X-Received: by 2002:a63:90ca:0:b0:3aa:fff3:6f76 with SMTP id a193-20020a6390ca000000b003aafff36f76mr631072pge.206.1651259093865; Fri, 29 Apr 2022 12:04:53 -0700 (PDT) MIME-Version: 1.0 References: <165119280115.15698.2629172320052218921.stgit@noble.brown> <165119301488.15698.9457662928942765453.stgit@noble.brown> In-Reply-To: <165119301488.15698.9457662928942765453.stgit@noble.brown> From: Yang Shi Date: Fri, 29 Apr 2022 12:04:41 -0700 Message-ID: Subject: Re: [PATCH 1/2] MM: handle THP in swap_*page_fs() To: NeilBrown Cc: Andrew Morton , Geert Uytterhoeven , Christoph Hellwig , Miaohe Lin , linux-nfs@vger.kernel.org, Linux MM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 6C5F4A0024 X-Stat-Signature: 3rcg5kbo77qencnr3ekh9ja9dgn4msdg Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=Ojqvo3+w; spf=pass (imf25.hostedemail.com: domain of shy828301@gmail.com designates 209.85.210.177 as permitted sender) smtp.mailfrom=shy828301@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-HE-Tag: 1651259085-330968 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, Apr 28, 2022 at 5:44 PM NeilBrown wrote: > > Pages passed to swap_readpage()/swap_writepage() are not necessarily all > the same size - there may be transparent-huge-pages involves. > > The BIO paths of swap_*page() handle this correctly, but the SWP_FS_OPS > path does not. > > So we need to use thp_size() to find the size, not just assume > PAGE_SIZE, and we need to track the total length of the request, not > just assume it is "page * PAGE_SIZE". Swap-over-nfs doesn't support THP swap IIUC. So SWP_FS_OPS should not see THP at all. But I agree to remove the assumption about page size in this path. > > Reported-by: Miaohe Lin > Signed-off-by: NeilBrown > --- > mm/page_io.c | 23 +++++++++++++---------- > 1 file changed, 13 insertions(+), 10 deletions(-) > > diff --git a/mm/page_io.c b/mm/page_io.c > index c132511f521c..d636a3531cad 100644 > --- a/mm/page_io.c > +++ b/mm/page_io.c > @@ -239,6 +239,7 @@ struct swap_iocb { > struct kiocb iocb; > struct bio_vec bvec[SWAP_CLUSTER_MAX]; > int pages; > + int len; > }; > static mempool_t *sio_pool; > > @@ -261,7 +262,7 @@ static void sio_write_complete(struct kiocb *iocb, long ret) > struct page *page = sio->bvec[0].bv_page; > int p; > > - if (ret != PAGE_SIZE * sio->pages) { > + if (ret != sio->len) { > /* > * In the case of swap-over-nfs, this can be a > * temporary failure if the system has limited > @@ -301,7 +302,7 @@ static int swap_writepage_fs(struct page *page, struct writeback_control *wbc) > sio = *wbc->swap_plug; > if (sio) { > if (sio->iocb.ki_filp != swap_file || > - sio->iocb.ki_pos + sio->pages * PAGE_SIZE != pos) { > + sio->iocb.ki_pos + sio->len != pos) { > swap_write_unplug(sio); > sio = NULL; > } > @@ -312,10 +313,12 @@ static int swap_writepage_fs(struct page *page, struct writeback_control *wbc) > sio->iocb.ki_complete = sio_write_complete; > sio->iocb.ki_pos = pos; > sio->pages = 0; > + sio->len = 0; > } > sio->bvec[sio->pages].bv_page = page; > - sio->bvec[sio->pages].bv_len = PAGE_SIZE; > + sio->bvec[sio->pages].bv_len = thp_size(page); > sio->bvec[sio->pages].bv_offset = 0; > + sio->len += thp_size(page); > sio->pages += 1; > if (sio->pages == ARRAY_SIZE(sio->bvec) || !wbc->swap_plug) { > swap_write_unplug(sio); > @@ -371,8 +374,7 @@ void swap_write_unplug(struct swap_iocb *sio) > struct address_space *mapping = sio->iocb.ki_filp->f_mapping; > int ret; > > - iov_iter_bvec(&from, WRITE, sio->bvec, sio->pages, > - PAGE_SIZE * sio->pages); > + iov_iter_bvec(&from, WRITE, sio->bvec, sio->pages, sio->len); > ret = mapping->a_ops->swap_rw(&sio->iocb, &from); > if (ret != -EIOCBQUEUED) > sio_write_complete(&sio->iocb, ret); > @@ -383,7 +385,7 @@ static void sio_read_complete(struct kiocb *iocb, long ret) > struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb); > int p; > > - if (ret == PAGE_SIZE * sio->pages) { > + if (ret == sio->len) { > for (p = 0; p < sio->pages; p++) { > struct page *page = sio->bvec[p].bv_page; > > @@ -415,7 +417,7 @@ static void swap_readpage_fs(struct page *page, > sio = *plug; > if (sio) { > if (sio->iocb.ki_filp != sis->swap_file || > - sio->iocb.ki_pos + sio->pages * PAGE_SIZE != pos) { > + sio->iocb.ki_pos + sio->len != pos) { > swap_read_unplug(sio); > sio = NULL; > } > @@ -426,10 +428,12 @@ static void swap_readpage_fs(struct page *page, > sio->iocb.ki_pos = pos; > sio->iocb.ki_complete = sio_read_complete; > sio->pages = 0; > + sio->len = 0; > } > sio->bvec[sio->pages].bv_page = page; > - sio->bvec[sio->pages].bv_len = PAGE_SIZE; > + sio->bvec[sio->pages].bv_len = thp_size(page); > sio->bvec[sio->pages].bv_offset = 0; > + sio->len += thp_size(page); > sio->pages += 1; > if (sio->pages == ARRAY_SIZE(sio->bvec) || !plug) { > swap_read_unplug(sio); > @@ -521,8 +525,7 @@ void __swap_read_unplug(struct swap_iocb *sio) > struct address_space *mapping = sio->iocb.ki_filp->f_mapping; > int ret; > > - iov_iter_bvec(&from, READ, sio->bvec, sio->pages, > - PAGE_SIZE * sio->pages); > + iov_iter_bvec(&from, READ, sio->bvec, sio->pages, sio->len); > ret = mapping->a_ops->swap_rw(&sio->iocb, &from); > if (ret != -EIOCBQUEUED) > sio_read_complete(&sio->iocb, ret); > > >