From patchwork Wed Feb 23 21:12:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 12757519 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 E00F9C433F5 for ; Wed, 23 Feb 2022 21:23:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242466AbiBWVWd (ORCPT ); Wed, 23 Feb 2022 16:22:33 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242426AbiBWVUG (ORCPT ); Wed, 23 Feb 2022 16:20:06 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED16B4ECD3 for ; Wed, 23 Feb 2022 13:19:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 5C645CE1C54 for ; Wed, 23 Feb 2022 21:19:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73F24C340E7 for ; Wed, 23 Feb 2022 21:19:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1645651174; bh=f4lIwUURxJwQZqENszJpvs17hM46N6azJSGI1p3XJpU=; h=From:To:Subject:Date:In-Reply-To:References:From; b=hW9uTyYl3ceWYz+lMqTWBs4s6/OF/Y/2hPP96zUqQ/VtVcTJWIueAlheKSwojl7Li hjNOln/4yQckINW7QTqehNXG4kLcdHclBSxS41gj03SWH3hTQnWMrA0XSsJdcDII1d 1aWu2rH/qjvOsyVeDs+kr/WNPOS4PTPL/ezB4x14X+IvIt76/f2xu56069bG07IWNs XUCR/jQMMB+xXfVgSWw9w7uZo43VZf2ddYqBUhAEBQES0e33l/w3sdLsfgf77rbWtc QnLnLTP3vGiAOeeU+FBajDlB8u9TG+hROITgCuNdkhH5o/MnUQqZHjAc0zDR9JeWig 7lOSzUgbZ0BgQ== From: trondmy@kernel.org To: linux-nfs@vger.kernel.org Subject: [PATCH v7 07/21] NFS: Don't re-read the entire page cache to find the next cookie Date: Wed, 23 Feb 2022 16:12:51 -0500 Message-Id: <20220223211305.296816-8-trondmy@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220223211305.296816-7-trondmy@kernel.org> References: <20220223211305.296816-1-trondmy@kernel.org> <20220223211305.296816-2-trondmy@kernel.org> <20220223211305.296816-3-trondmy@kernel.org> <20220223211305.296816-4-trondmy@kernel.org> <20220223211305.296816-5-trondmy@kernel.org> <20220223211305.296816-6-trondmy@kernel.org> <20220223211305.296816-7-trondmy@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Trond Myklebust If the page cache entry that was last read gets invalidated for some reason, then make sure we can re-create it on the next call to readdir. This, combined with the cache page validation, allows us to reuse the cached value of page-index on successive calls to nfs_readdir. Credit is due to Benjamin Coddington for showing that the concept works, and that it allows for improved cache sharing between processes even in the case where pages are lost due to LRU or active invalidation. Suggested-by: Benjamin Coddington Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 10 +++++++--- include/linux/nfs_fs.h | 1 + 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index 7932d474ce00..70c0db877815 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1124,6 +1124,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) desc->dup_cookie = dir_ctx->dup_cookie; desc->duped = dir_ctx->duped; page_index = dir_ctx->page_index; + desc->page_index = page_index; + desc->last_cookie = dir_ctx->last_cookie; desc->attr_gencount = dir_ctx->attr_gencount; desc->eof = dir_ctx->eof; memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf)); @@ -1172,6 +1174,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) spin_lock(&file->f_lock); dir_ctx->dir_cookie = desc->dir_cookie; dir_ctx->dup_cookie = desc->dup_cookie; + dir_ctx->last_cookie = desc->last_cookie; dir_ctx->duped = desc->duped; dir_ctx->attr_gencount = desc->attr_gencount; dir_ctx->page_index = desc->page_index; @@ -1213,10 +1216,11 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence) } if (offset != filp->f_pos) { filp->f_pos = offset; - if (nfs_readdir_use_cookie(filp)) - dir_ctx->dir_cookie = offset; - else + if (!nfs_readdir_use_cookie(filp)) { dir_ctx->dir_cookie = 0; + dir_ctx->page_index = 0; + } else + dir_ctx->dir_cookie = offset; if (offset == 0) memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf)); dir_ctx->duped = 0; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 6e10725887d1..1c533f2c1f36 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -105,6 +105,7 @@ struct nfs_open_dir_context { __be32 verf[NFS_DIR_VERIFIER_SIZE]; __u64 dir_cookie; __u64 dup_cookie; + __u64 last_cookie; pgoff_t page_index; signed char duped; bool eof;