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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY 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 2EB15C433E4 for ; Fri, 21 Aug 2020 17:30:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CB0A20656 for ; Fri, 21 Aug 2020 17:30:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UCJyXfmI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728922AbgHUR3y (ORCPT ); Fri, 21 Aug 2020 13:29:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728073AbgHUR3m (ORCPT ); Fri, 21 Aug 2020 13:29:42 -0400 Received: from mail-vs1-xe41.google.com (mail-vs1-xe41.google.com [IPv6:2607:f8b0:4864:20::e41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 40F80C061574; Fri, 21 Aug 2020 10:29:42 -0700 (PDT) Received: by mail-vs1-xe41.google.com with SMTP id y8so1199954vsq.8; Fri, 21 Aug 2020 10:29:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc:content-transfer-encoding; bh=smI891Q3FmbjoOIjkCuWKAVNd1ZCWF+ht5pb17V8UgE=; b=UCJyXfmIKgNC62T6Xdn/l7EP9RL7W+CqActf9YsyCdLnc9i3oZ828de5S1KnEBTC7j tWXLqKVNipQE3tSydzwTxaEZw3qWh9cP12bucoNi8POAOn750/gHLU1wgVgit2laP+q6 UdXWF9qsHrYAfYJl0uNH0jjaMzqmpfdCvctB9LLnmpul7+qsUfRnLvlx62v5Z8pvAGeH d+xfFnOZo0zd5honRrNP87i6n98p5Jv9EaIQLLalz57FM+M0bK2gktTkhxfCa6sVhknm xD4YIvcuUCZSLrR+3jnmI0SJI9ZzwdlKX0o96vwaG9dSWnh9mTHMoDhdCJ/pfMvwvSTr tGYQ== 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:reply-to :from:date:message-id:subject:to:cc:content-transfer-encoding; bh=smI891Q3FmbjoOIjkCuWKAVNd1ZCWF+ht5pb17V8UgE=; b=d5WBgxj3qCrO2b7JY8ZcSDMu4+Cq7kFzQSm9h6CpmscsYBAJGTD0J1siVP1e3WMHQz c+pl2NQeI14pbVVGTLEJsKRalLgO5iupyRJlXyWYYoTlGddtgv8yZYavMJUyJt7yege+ oSUC2dxPZzj3cexJmr86zLfa6aVE7ROkJnDcQBiiB9xZysmHTtOKQrB+kRvzrFHiHB2E JbHkMde4NAZGtZIrd5C0ePiPTr95y2766SrJPeSR2KUdAEvd5xu5XkkPch44pGNxppsj xw3PFyxrKIYM0dK2VId6Z8IKySTy5PBQwroiY5pu87/2QLKTyM/5oCIuNVoN+7gM2ge8 rjfQ== X-Gm-Message-State: AOAM532WrwQea0WlaEN0PSPFqD4qnnDOk2q9K4A6be7dX7OwvIP4H+X4 r8pkOoCypXgRtiRDRoITUIqG11srbYcze7GSbSZHKxrmNu4= X-Google-Smtp-Source: ABdhPJxzMzpbJ+XRrSz2W8dM9AE6lRGIiqMsSixhS2DvNwbAW4CyjdavwkcvOVbeWflT4/WWsjyw56Wwvfd+OtOQs0g= X-Received: by 2002:a67:e40a:: with SMTP id d10mr2473468vsf.95.1598030981392; Fri, 21 Aug 2020 10:29:41 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Reply-To: fdmanana@gmail.com From: Filipe Manana Date: Fri, 21 Aug 2020 18:29:30 +0100 Message-ID: Subject: Re: [PATCH 2/9] btrfs: send: avoid copying file data To: Omar Sandoval Cc: linux-btrfs , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Aug 21, 2020 at 8:42 AM Omar Sandoval wrote: > > From: Omar Sandoval > > send_write() currently copies from the page cache to sctx->read_buf, and > then from sctx->read_buf to sctx->send_buf. Similarly, send_hole() > zeroes sctx->read_buf and then copies from sctx->read_buf to > sctx->send_buf. However, if we write the TLV header manually, we can > copy to sctx->send_buf directly and get rid of sctx->read_buf. > > Signed-off-by: Omar Sandoval Reviewed-by: Filipe Manana Looks good, and it passed some long duration tests with both full and incremental sends here (with and without compression, no-holes, etc). Only one minor thing below, but it's really subjective and doesn't make much of a difference. Thanks. > --- > fs/btrfs/send.c | 65 +++++++++++++++++++++++++++++-------------------- > fs/btrfs/send.h | 1 - > 2 files changed, 39 insertions(+), 27 deletions(-) > > diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c > index 8af5e867e4ca..e70f5ceb3261 100644 > --- a/fs/btrfs/send.c > +++ b/fs/btrfs/send.c > @@ -122,8 +122,6 @@ struct send_ctx { > > struct file_ra_state ra; > > - char *read_buf; > - > /* > * We process inodes by their increasing order, so if before an > * incremental send we reverse the parent/child relationship of > @@ -4794,7 +4792,25 @@ static int process_all_new_xattrs(struct send_ctx = *sctx) > return ret; > } > > -static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len) > +static u64 max_send_read_size(struct send_ctx *sctx) We could make this inline, since it's so small and trivial, and constify the argument too. > +{ > + return sctx->send_max_size - SZ_16K; > +} > + > +static int put_data_header(struct send_ctx *sctx, u32 len) > +{ > + struct btrfs_tlv_header *hdr; > + > + if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len) > + return -EOVERFLOW; > + hdr =3D (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_s= ize); > + hdr->tlv_type =3D cpu_to_le16(BTRFS_SEND_A_DATA); > + hdr->tlv_len =3D cpu_to_le16(len); > + sctx->send_size +=3D sizeof(*hdr); > + return 0; > +} > + > +static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len) > { > struct btrfs_root *root =3D sctx->send_root; > struct btrfs_fs_info *fs_info =3D root->fs_info; > @@ -4804,8 +4820,11 @@ static int fill_read_buf(struct send_ctx *sctx, u6= 4 offset, u32 len) > pgoff_t index =3D offset >> PAGE_SHIFT; > pgoff_t last_index; > unsigned pg_offset =3D offset_in_page(offset); > - int ret =3D 0; > - size_t read =3D 0; > + int ret; > + > + ret =3D put_data_header(sctx, len); > + if (ret) > + return ret; > > inode =3D btrfs_iget(fs_info->sb, sctx->cur_ino, root); > if (IS_ERR(inode)) > @@ -4851,14 +4870,15 @@ static int fill_read_buf(struct send_ctx *sctx, u= 64 offset, u32 len) > } > > addr =3D kmap(page); > - memcpy(sctx->read_buf + read, addr + pg_offset, cur_len); > + memcpy(sctx->send_buf + sctx->send_size, addr + pg_offset= , > + cur_len); > kunmap(page); > unlock_page(page); > put_page(page); > index++; > pg_offset =3D 0; > len -=3D cur_len; > - read +=3D cur_len; > + sctx->send_size +=3D cur_len; > } > iput(inode); > return ret; > @@ -4880,10 +4900,6 @@ static int send_write(struct send_ctx *sctx, u64 o= ffset, u32 len) > > btrfs_debug(fs_info, "send_write offset=3D%llu, len=3D%d", offset= , len); > > - ret =3D fill_read_buf(sctx, offset, len); > - if (ret < 0) > - goto out; > - > ret =3D begin_cmd(sctx, BTRFS_SEND_C_WRITE); > if (ret < 0) > goto out; > @@ -4894,7 +4910,9 @@ static int send_write(struct send_ctx *sctx, u64 of= fset, u32 len) > > TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); > TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); > - TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len); > + ret =3D put_file_data(sctx, offset, len); > + if (ret < 0) > + goto out; > > ret =3D send_cmd(sctx); > > @@ -5013,8 +5031,8 @@ static int send_update_extent(struct send_ctx *sctx= , > static int send_hole(struct send_ctx *sctx, u64 end) > { > struct fs_path *p =3D NULL; > + u64 read_size =3D max_send_read_size(sctx); > u64 offset =3D sctx->cur_inode_last_extent; > - u64 len; > int ret =3D 0; > > /* > @@ -5041,16 +5059,19 @@ static int send_hole(struct send_ctx *sctx, u64 e= nd) > ret =3D get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p)= ; > if (ret < 0) > goto tlv_put_failure; > - memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE); > while (offset < end) { > - len =3D min_t(u64, end - offset, BTRFS_SEND_READ_SIZE); > + u64 len =3D min(end - offset, read_size); > > ret =3D begin_cmd(sctx, BTRFS_SEND_C_WRITE); > if (ret < 0) > break; > TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p); > TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset); > - TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len); > + ret =3D put_data_header(sctx, len); > + if (ret < 0) > + break; > + memset(sctx->send_buf + sctx->send_size, 0, len); > + sctx->send_size +=3D len; > ret =3D send_cmd(sctx); > if (ret < 0) > break; > @@ -5066,17 +5087,16 @@ static int send_extent_data(struct send_ctx *sctx= , > const u64 offset, > const u64 len) > { > + u64 read_size =3D max_send_read_size(sctx); > u64 sent =3D 0; > > if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) > return send_update_extent(sctx, offset, len); > > while (sent < len) { > - u64 size =3D len - sent; > + u64 size =3D min(len - sent, read_size); > int ret; > > - if (size > BTRFS_SEND_READ_SIZE) > - size =3D BTRFS_SEND_READ_SIZE; > ret =3D send_write(sctx, offset + sent, size); > if (ret < 0) > return ret; > @@ -7145,12 +7165,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struc= t btrfs_ioctl_send_args *arg) > goto out; > } > > - sctx->read_buf =3D kvmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL); > - if (!sctx->read_buf) { > - ret =3D -ENOMEM; > - goto out; > - } > - > sctx->pending_dir_moves =3D RB_ROOT; > sctx->waiting_dir_moves =3D RB_ROOT; > sctx->orphan_dirs =3D RB_ROOT; > @@ -7354,7 +7368,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct= btrfs_ioctl_send_args *arg) > > kvfree(sctx->clone_roots); > kvfree(sctx->send_buf); > - kvfree(sctx->read_buf); > > name_cache_free(sctx); > > diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h > index ead397f7034f..de91488b7cd0 100644 > --- a/fs/btrfs/send.h > +++ b/fs/btrfs/send.h > @@ -13,7 +13,6 @@ > #define BTRFS_SEND_STREAM_VERSION 1 > > #define BTRFS_SEND_BUF_SIZE SZ_64K > -#define BTRFS_SEND_READ_SIZE (48 * SZ_1K) > > enum btrfs_tlv_type { > BTRFS_TLV_U8, > -- > 2.28.0 > --=20 Filipe David Manana, =E2=80=9CWhether you think you can, or you think you can't =E2=80=94 you're= right.=E2=80=9D