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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C8C0CCA47B for ; Wed, 8 Jun 2022 17:25:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231701AbiFHRZi (ORCPT ); Wed, 8 Jun 2022 13:25:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52018 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231977AbiFHRZK (ORCPT ); Wed, 8 Jun 2022 13:25:10 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 587F262F2 for ; Wed, 8 Jun 2022 10:20:56 -0700 (PDT) Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 258FPPVL015675 for ; Wed, 8 Jun 2022 10:20:55 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=SanAPp/GdGsVkoF9K0kGfp+PZp6DCWAFgZk5IqjhpxA=; b=L+urSaRVR7SZ5Grd7D4L1zw+DMhx79CRMf7aYsPks1mQbg3XSKm7CNcwaV1xCvD5jliY Fi9DzWjggu7BF/uVDpRCZEWp0B4d7Sw4JobZqQMAjujz8/dCpdBRtk3YcmVpoa3nSv7V G3oyA/irklRwiEpGXJQo5/4RUXRLzVmtqGs= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3gjr0jb0vx-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 08 Jun 2022 10:20:55 -0700 Received: from twshared17349.03.ash7.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.28; Wed, 8 Jun 2022 10:20:54 -0700 Received: by devvm225.atn0.facebook.com (Postfix, from userid 425415) id 99EED103BFB5B; Wed, 8 Jun 2022 10:17:43 -0700 (PDT) From: Stefan Roesch To: , , , , CC: , , , , , Christoph Hellwig Subject: [PATCH v8 05/14] iomap: Add async buffered write support Date: Wed, 8 Jun 2022 10:17:32 -0700 Message-ID: <20220608171741.3875418-6-shr@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220608171741.3875418-1-shr@fb.com> References: <20220608171741.3875418-1-shr@fb.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-ORIG-GUID: NF3HMmCwdvb5BlY-QuMCJqfjdYYsbe3s X-Proofpoint-GUID: NF3HMmCwdvb5BlY-QuMCJqfjdYYsbe3s X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-08_05,2022-06-07_02,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This adds async buffered write support to iomap. This replaces the call to balance_dirty_pages_ratelimited() with the call to balance_dirty_pages_ratelimited_flags. This allows to specify if the write request is async or not. In addition this also moves the above function call to the beginning of the function. If the function call is at the end of the function and the decision is made to throttle writes, then there is no request that io-uring can wait on. By moving it to the beginning of the function, the write request is not issued, but returns -EAGAIN instead. io-uring will punt the request and process it in the io-worker. By moving the function call to the beginning of the function, the write throttling will happen one page later. Signed-off-by: Stefan Roesch Reviewed-by: Jan Kara Reviewed-by: Christoph Hellwig --- fs/iomap/buffered-io.c | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 705f80cd2d4e..b06a5c24a4db 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -558,6 +558,7 @@ static int __iomap_write_begin(const struct iomap_ite= r *iter, loff_t pos, loff_t block_size =3D i_blocksize(iter->inode); loff_t block_start =3D round_down(pos, block_size); loff_t block_end =3D round_up(pos + len, block_size); + unsigned int nr_blocks =3D i_blocks_per_folio(iter->inode, folio); size_t from =3D offset_in_folio(folio, pos), to =3D from + len; size_t poff, plen; =20 @@ -566,6 +567,8 @@ static int __iomap_write_begin(const struct iomap_ite= r *iter, loff_t pos, folio_clear_error(folio); =20 iop =3D iomap_page_create(iter->inode, folio, iter->flags); + if ((iter->flags & IOMAP_NOWAIT) && !iop && nr_blocks > 1) + return -EAGAIN; =20 do { iomap_adjust_read_range(iter->inode, folio, &block_start, @@ -583,7 +586,12 @@ static int __iomap_write_begin(const struct iomap_it= er *iter, loff_t pos, return -EIO; folio_zero_segments(folio, poff, from, to, poff + plen); } else { - int status =3D iomap_read_folio_sync(block_start, folio, + int status; + + if (iter->flags & IOMAP_NOWAIT) + return -EAGAIN; + + status =3D iomap_read_folio_sync(block_start, folio, poff, plen, srcmap); if (status) return status; @@ -612,6 +620,9 @@ static int iomap_write_begin(const struct iomap_iter = *iter, loff_t pos, unsigned fgp =3D FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE | FGP_NO= FS; int status =3D 0; =20 + if (iter->flags & IOMAP_NOWAIT) + fgp |=3D FGP_NOWAIT; + BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length); if (srcmap !=3D &iter->iomap) BUG_ON(pos + len > srcmap->offset + srcmap->length); @@ -631,7 +642,7 @@ static int iomap_write_begin(const struct iomap_iter = *iter, loff_t pos, folio =3D __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT= , fgp, mapping_gfp_mask(iter->inode->i_mapping)); if (!folio) { - status =3D -ENOMEM; + status =3D (iter->flags & IOMAP_NOWAIT) ? -EAGAIN : -ENOMEM; goto out_no_page; } if (pos + len > folio_pos(folio) + folio_size(folio)) @@ -749,6 +760,8 @@ static loff_t iomap_write_iter(struct iomap_iter *ite= r, struct iov_iter *i) loff_t pos =3D iter->pos; ssize_t written =3D 0; long status =3D 0; + struct address_space *mapping =3D iter->inode->i_mapping; + unsigned int bdp_flags =3D (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0= ; =20 do { struct folio *folio; @@ -761,6 +774,11 @@ static loff_t iomap_write_iter(struct iomap_iter *it= er, struct iov_iter *i) bytes =3D min_t(unsigned long, PAGE_SIZE - offset, iov_iter_count(i)); again: + status =3D balance_dirty_pages_ratelimited_flags(mapping, + bdp_flags); + if (unlikely(status)) + break; + if (bytes > length) bytes =3D length; =20 @@ -769,6 +787,10 @@ static loff_t iomap_write_iter(struct iomap_iter *it= er, struct iov_iter *i) * Otherwise there's a nasty deadlock on copying from the * same page as we're writing to, without it being marked * up-to-date. + * + * For async buffered writes the assumption is that the user + * page has already been faulted in. This can be optimized by + * faulting the user page. */ if (unlikely(fault_in_iov_iter_readable(i, bytes) =3D=3D bytes)) { status =3D -EFAULT; @@ -780,7 +802,7 @@ static loff_t iomap_write_iter(struct iomap_iter *ite= r, struct iov_iter *i) break; =20 page =3D folio_file_page(folio, pos >> PAGE_SHIFT); - if (mapping_writably_mapped(iter->inode->i_mapping)) + if (mapping_writably_mapped(mapping)) flush_dcache_page(page); =20 copied =3D copy_page_from_iter_atomic(page, offset, bytes, i); @@ -805,8 +827,6 @@ static loff_t iomap_write_iter(struct iomap_iter *ite= r, struct iov_iter *i) pos +=3D status; written +=3D status; length -=3D status; - - balance_dirty_pages_ratelimited(iter->inode->i_mapping); } while (iov_iter_count(i) && length); =20 return written ? written : status; @@ -824,6 +844,9 @@ iomap_file_buffered_write(struct kiocb *iocb, struct = iov_iter *i, }; int ret; =20 + if (iocb->ki_flags & IOCB_NOWAIT) + iter.flags |=3D IOMAP_NOWAIT; + while ((ret =3D iomap_iter(&iter, ops)) > 0) iter.processed =3D iomap_write_iter(&iter, i); if (iter.pos =3D=3D iocb->ki_pos) --=20 2.30.2