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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 4BB1BC2D0BF for ; Tue, 10 Dec 2019 20:43:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 03E402073B for ; Tue, 10 Dec 2019 20:43:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="VC4R6EkX" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 03E402073B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 632AC6B2E37; Tue, 10 Dec 2019 15:43:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 594056B2E3A; Tue, 10 Dec 2019 15:43:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 483D46B2E39; Tue, 10 Dec 2019 15:43:12 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id 338A16B2E37 for ; Tue, 10 Dec 2019 15:43:12 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 05208180AD81A for ; Tue, 10 Dec 2019 20:43:12 +0000 (UTC) X-FDA: 76250406624.27.curve18_5614c402a8f50 X-HE-Tag: curve18_5614c402a8f50 X-Filterd-Recvd-Size: 7662 Received: from mail-pf1-f195.google.com (mail-pf1-f195.google.com [209.85.210.195]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Tue, 10 Dec 2019 20:43:11 +0000 (UTC) Received: by mail-pf1-f195.google.com with SMTP id p14so416422pfn.4 for ; Tue, 10 Dec 2019 12:43:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=g934jRFitGK2n249ARajPKYt/UpPdfJOZffggpxpM9A=; b=VC4R6EkXXjbtQxDiwSsKD2cJRnJF2ODuAL3j8ivGaSeswr6nBQpNBzBjn+q/Vcpeil ycZ+Ao2nHQq7myQuMGD4fppkVnNgT+lLMObOnSHXDraX/2V7KQWkp73TSXf1iEqwkpvh kxQ8tBtG4h00b0Cq5hSe/+zR7dUYXOklLtS4yzNx4n754+9LRSDtzwF0BM5zDwGWJlI4 LCO18i09Xt9xIgLpbQJlOKGBukiM2Ye2CGcaYQrV5tIalX34nIHITLjJAnryr2uiaQnQ H1JJKa0QJQNhA30TOcOpwFn6uj1aSiDWyQ1shW2UC8FJjuPu8Dy3GnqYQgccuq7auwLV eXZQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=g934jRFitGK2n249ARajPKYt/UpPdfJOZffggpxpM9A=; b=L0GFJBBDrPHI56sOpd9I9ZkoysRou2TUdsU/9nuEUM1w+w05gGfeiuhMlqGclcJkWB 70W3CxmYqU5o6WiyJg4h7fCnGJKUkFFs5dYlDZj6YAFJ03PdAG755K+8cfOTSlkF+Qbj DUeNqm2tYSUtCkrYGCHHtOJnStEPMRTR1jkMLfesdD1Yd4bGYnSFmNvkDLgUXL6JVBM0 XRva+u4JirM4736961MyGe9wXvYFqKRrolp9z8pRixATUUV6E1rLRCnK3qp8qYs4hxuj L7tfD+JoA/OkwAp12CYifeIOk5IxKdr6cwO9GLj9YMo1hepKOgNuLCjueMuiMRSfYa4l n9cQ== X-Gm-Message-State: APjAAAXv8bCHtCWAGZoklYg7labpF5Vo84Lb4v6wXxtH+HRi6+XXa6Rm lpMBe7uY33nv5wjNr0Rs2EKWuucZs3FzRw== X-Google-Smtp-Source: APXvYqyE5WoFA/cmJn1vJRX9pzPgXF2eR410xgWfmk3FD8JEs9EuTw5uMmkjPyn17EKlZwqDrRxS2A== X-Received: by 2002:a62:788a:: with SMTP id t132mr29104312pfc.134.1576010589664; Tue, 10 Dec 2019 12:43:09 -0800 (PST) Received: from x1.thefacebook.com ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id o15sm4387829pgf.2.2019.12.10.12.43.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Dec 2019 12:43:08 -0800 (PST) From: Jens Axboe To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org Cc: willy@infradead.org, clm@fb.com, Jens Axboe Subject: [PATCH 1/5] fs: add read support for RWF_UNCACHED Date: Tue, 10 Dec 2019 13:43:00 -0700 Message-Id: <20191210204304.12266-2-axboe@kernel.dk> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191210204304.12266-1-axboe@kernel.dk> References: <20191210204304.12266-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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: If RWF_UNCACHED is set for io_uring (or preadv2(2)), we'll drop the cache for buffered reads if we are the ones instantiating it. If the data is already cached, we leave it cached. Signed-off-by: Jens Axboe --- include/linux/fs.h | 3 +++ include/uapi/linux/fs.h | 5 ++++- mm/filemap.c | 46 ++++++++++++++++++++++++++++++++++++----- 3 files changed, 48 insertions(+), 6 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 98e0349adb52..092ea2a4319b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -314,6 +314,7 @@ enum rw_hint { #define IOCB_SYNC (1 << 5) #define IOCB_WRITE (1 << 6) #define IOCB_NOWAIT (1 << 7) +#define IOCB_UNCACHED (1 << 8) =20 struct kiocb { struct file *ki_filp; @@ -3418,6 +3419,8 @@ static inline int kiocb_set_rw_flags(struct kiocb *= ki, rwf_t flags) ki->ki_flags |=3D (IOCB_DSYNC | IOCB_SYNC); if (flags & RWF_APPEND) ki->ki_flags |=3D IOCB_APPEND; + if (flags & RWF_UNCACHED) + ki->ki_flags |=3D IOCB_UNCACHED; return 0; } =20 diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 379a612f8f1d..357ebb0e0c5d 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -299,8 +299,11 @@ typedef int __bitwise __kernel_rwf_t; /* per-IO O_APPEND */ #define RWF_APPEND ((__force __kernel_rwf_t)0x00000010) =20 +/* drop cache after reading or writing data */ +#define RWF_UNCACHED ((__force __kernel_rwf_t)0x00000040) + /* mask of flags supported by the kernel */ #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ - RWF_APPEND) + RWF_APPEND | RWF_UNCACHED) =20 #endif /* _UAPI_LINUX_FS_H */ diff --git a/mm/filemap.c b/mm/filemap.c index bf6aa30be58d..ed23a11b3e34 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -933,8 +933,8 @@ int add_to_page_cache_locked(struct page *page, struc= t address_space *mapping, } EXPORT_SYMBOL(add_to_page_cache_locked); =20 -int add_to_page_cache_lru(struct page *page, struct address_space *mappi= ng, - pgoff_t offset, gfp_t gfp_mask) +static int __add_to_page_cache(struct page *page, struct address_space *= mapping, + pgoff_t offset, gfp_t gfp_mask, bool lru) { void *shadow =3D NULL; int ret; @@ -956,9 +956,17 @@ int add_to_page_cache_lru(struct page *page, struct = address_space *mapping, WARN_ON_ONCE(PageActive(page)); if (!(gfp_mask & __GFP_WRITE) && shadow) workingset_refault(page, shadow); - lru_cache_add(page); + if (lru) + lru_cache_add(page); } return ret; + +} + +int add_to_page_cache_lru(struct page *page, struct address_space *mappi= ng, + pgoff_t offset, gfp_t gfp_mask) +{ + return __add_to_page_cache(page, mapping, offset, gfp_mask, true); } EXPORT_SYMBOL_GPL(add_to_page_cache_lru); =20 @@ -2032,6 +2040,7 @@ static ssize_t generic_file_buffered_read(struct ki= ocb *iocb, offset =3D *ppos & ~PAGE_MASK; =20 for (;;) { + bool drop_page =3D false; struct page *page; pgoff_t end_index; loff_t isize; @@ -2048,6 +2057,9 @@ static ssize_t generic_file_buffered_read(struct ki= ocb *iocb, if (!page) { if (iocb->ki_flags & IOCB_NOWAIT) goto would_block; + /* UNCACHED implies no read-ahead */ + if (iocb->ki_flags & IOCB_UNCACHED) + goto no_cached_page; page_cache_sync_readahead(mapping, ra, filp, index, last_index - index); @@ -2147,6 +2159,26 @@ static ssize_t generic_file_buffered_read(struct k= iocb *iocb, offset &=3D ~PAGE_MASK; prev_offset =3D offset; =20 + /* + * If we're dropping this page due to drop-behind, then + * lock it first. Ignore errors here, we can just leave it + * in the page cache. Note that we didn't add this page to + * the LRU when we added it to the page cache. So if we + * fail removing it, or lock it, add to the LRU. + */ + if (drop_page) { + bool addlru =3D true; + + if (!lock_page_killable(page)) { + if (page->mapping =3D=3D mapping) + addlru =3D !remove_mapping(mapping, page); + else + addlru =3D false; + unlock_page(page); + } + if (addlru) + lru_cache_add(page); + } put_page(page); written +=3D ret; if (!iov_iter_count(iter)) @@ -2234,8 +2266,12 @@ static ssize_t generic_file_buffered_read(struct k= iocb *iocb, error =3D -ENOMEM; goto out; } - error =3D add_to_page_cache_lru(page, mapping, index, - mapping_gfp_constraint(mapping, GFP_KERNEL)); + if (iocb->ki_flags & IOCB_UNCACHED) + drop_page =3D true; + + error =3D __add_to_page_cache(page, mapping, index, + mapping_gfp_constraint(mapping, GFP_KERNEL), + !drop_page); if (error) { put_page(page); if (error =3D=3D -EEXIST) { --=20 2.24.0