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Tue, 14 Apr 2020 15:02:52 GMT Received: from userp2040.oracle.com (userp2040.oracle.com [156.151.31.90]) by aserp3020.oracle.com with ESMTP id 30bqpgsx1t-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Tue, 14 Apr 2020 15:02:52 +0000 Received: from pps.filterd (userp2040.oracle.com [127.0.0.1]) by userp2040.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03EExq5C046931 for ; Tue, 14 Apr 2020 15:02:51 GMT Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by userp2040.oracle.com with ESMTP id 30d6x10jpu-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Tue, 14 Apr 2020 15:02:51 +0000 Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jON5A-0006Ol-4U; Tue, 14 Apr 2020 15:02:36 +0000 From: Matthew Wilcox To: Andrew Morton Date: Tue, 14 Apr 2020 08:02:20 -0700 Message-Id: <20200414150233.24495-13-willy@infradead.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200414150233.24495-1-willy@infradead.org> References: <20200414150233.24495-1-willy@infradead.org> MIME-Version: 1.0 X-PDR: PASS X-Source-IP: 198.137.202.133 X-ServerName: bombadil.infradead.org X-Proofpoint-SPF-Result: None X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9591 signatures=668686 X-Proofpoint-Spam-Details: rule=tap_spam_policies_notspam policy=tap_spam_policies score=0 lowpriorityscore=0 clxscore=194 impostorscore=0 bulkscore=0 phishscore=0 priorityscore=0 malwarescore=0 spamscore=0 mlxlogscore=999 mlxscore=0 adultscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004140122 X-Spam: Clean X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 malwarescore=0 adultscore=0 bulkscore=0 spamscore=0 suspectscore=0 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004140122 Cc: linux-xfs@vger.kernel.org, William Kucharski , John Hubbard , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-mm@kvack.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org Subject: [Ocfs2-devel] [PATCH v11 12/25] mm: Move end_index check out of readahead loop X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9591 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=999 bulkscore=0 malwarescore=0 phishscore=0 mlxscore=0 spamscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004140122 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9591 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 clxscore=1034 bulkscore=0 mlxscore=0 mlxlogscore=999 lowpriorityscore=0 impostorscore=0 adultscore=0 phishscore=0 spamscore=0 suspectscore=0 malwarescore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004140122 From: "Matthew Wilcox (Oracle)" By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: John Hubbard Reviewed-by: William Kucharski --- mm/readahead.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index d01531ef9f3c..998fdd23c0b1 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -167,8 +167,6 @@ void __do_page_cache_readahead(struct address_space *mapping, unsigned long lookahead_size) { struct inode *inode = mapping->host; - struct page *page; - unsigned long end_index; /* The last page we want to read */ LIST_HEAD(page_pool); loff_t isize = i_size_read(inode); gfp_t gfp_mask = readahead_gfp_mask(mapping); @@ -178,22 +176,26 @@ void __do_page_cache_readahead(struct address_space *mapping, ._index = index, }; unsigned long i; + pgoff_t end_index; /* The last page we want to read */ if (isize == 0) return; - end_index = ((isize - 1) >> PAGE_SHIFT); + end_index = (isize - 1) >> PAGE_SHIFT; + if (index > end_index) + return; + /* Don't read past the page containing the last byte of the file */ + if (nr_to_read > end_index - index) + nr_to_read = end_index - index + 1; /* * Preallocate as many pages as we will need. */ for (i = 0; i < nr_to_read; i++) { - if (index + i > end_index) - break; + struct page *page = xa_load(&mapping->i_pages, index + i); BUG_ON(index + i != rac._index + rac._nr_pages); - page = xa_load(&mapping->i_pages, index + i); if (page && !xa_is_value(page)) { /* * Page already present? Kick off the current batch of