From: Austin Clements Date: Thu, 24 Oct 2013 21:38:59 +0000 (+2000) Subject: [PATCH v2] new: Don't scan unchanged directories with no sub-directories X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=242e8008a7de2b3d1408f11e264c9f2a1e3af621;p=notmuch-archives.git [PATCH v2] new: Don't scan unchanged directories with no sub-directories --- diff --git a/50/c1d3b65cedca67accd73659a1d30ab3005287d b/50/c1d3b65cedca67accd73659a1d30ab3005287d new file mode 100644 index 000000000..84da2db5e --- /dev/null +++ b/50/c1d3b65cedca67accd73659a1d30ab3005287d @@ -0,0 +1,126 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id CC891431FC2 + for ; Thu, 24 Oct 2013 14:39:18 -0700 (PDT) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Spam-Flag: NO +X-Spam-Score: -0.7 +X-Spam-Level: +X-Spam-Status: No, score=-0.7 tagged_above=-999 required=5 + tests=[RCVD_IN_DNSWL_LOW=-0.7] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id R3cJTEIAWxAz for ; + Thu, 24 Oct 2013 14:39:11 -0700 (PDT) +Received: from dmz-mailsec-scanner-2.mit.edu (dmz-mailsec-scanner-2.mit.edu + [18.9.25.13]) + by olra.theworths.org (Postfix) with ESMTP id 26FD1431FB6 + for ; Thu, 24 Oct 2013 14:39:11 -0700 (PDT) +X-AuditID: 1209190d-b7f528e0000009b4-08-5269937ead0a +Received: from mailhub-auth-1.mit.edu ( [18.9.21.35]) + by dmz-mailsec-scanner-2.mit.edu (Symantec Messaging Gateway) with SMTP + id 06.26.02484.E7399625; Thu, 24 Oct 2013 17:39:10 -0400 (EDT) +Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) + by mailhub-auth-1.mit.edu (8.13.8/8.9.2) with ESMTP id r9OLd825031538; + Thu, 24 Oct 2013 17:39:08 -0400 +Received: from drake.dyndns.org (26-4-172.dynamic.csail.mit.edu [18.26.4.172]) + (authenticated bits=0) + (User authenticated as amdragon@ATHENA.MIT.EDU) + by outgoing.mit.edu (8.13.8/8.12.4) with ESMTP id r9OLd6qB010508 + (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=NOT); + Thu, 24 Oct 2013 17:39:07 -0400 +Received: from amthrax by drake.dyndns.org with local (Exim 4.77) + (envelope-from ) + id 1VZScU-0003Gj-89; Thu, 24 Oct 2013 17:39:06 -0400 +From: Austin Clements +To: notmuch@notmuchmail.org +Subject: [PATCH v2] new: Don't scan unchanged directories with no + sub-directories +Date: Thu, 24 Oct 2013 17:38:59 -0400 +Message-Id: <1382650739-12438-1-git-send-email-amdragon@mit.edu> +X-Mailer: git-send-email 1.8.4.rc3 +In-Reply-To: <20131024210837.GH20337@mit.edu> +References: <20131024210837.GH20337@mit.edu> +X-Brightmail-Tracker: + H4sIAAAAAAAAA+NgFtrLIsWRmVeSWpSXmKPExsUixCmqrFs3OTPIYPNZdYvrN2cyW3Tc3s3m + wOTxbNUtZo+PT2+xBDBFcdmkpOZklqUW6dslcGXM6q0uuCBU8ePMdPYGxvV8XYycHBICJhJb + 53WyQ9hiEhfurWfrYuTiEBLYxyjxpfUHE4SzkVHi1OW3jBDOESaJpzunsEM4cxkldr3eyAjS + zyagIbFt/3IwW0RAWmLn3dmsIDazgKPEngPLWUBsYYFAidnHb4DVsAioSiy8PwWshlfAQaLn + 0lY2iDuUJBae2gYW5xTQlTi07RATiC0koCNxo+kN4wRG/gWMDKsYZVNyq3RzEzNzilOTdYuT + E/PyUot0jfRyM0v0UlNKNzGCQ0mSdwfju4NKhxgFOBiVeHg1PqQHCbEmlhVX5h5ilORgUhLl + NZ6UGSTEl5SfUpmRWJwRX1Sak1p8iFGCg1lJhHeaHlCONyWxsiq1KB8mJc3BoiTOe5PDPkhI + ID2xJDU7NbUgtQgmK8PBoSTBGw8yVLAoNT21Ii0zpwQhzcTBCTKcB2h4FkgNb3FBYm5xZjpE + /hSjopQ47waQhABIIqM0D64XFuuvGMWBXhHmrQSp4gGmCbjuV0CDmYAGT1mSBjK4JBEhJdXA + KJlbWCsr83PiVstOn8wlwgvv9aa/W/uyUYBb9cuBh0dTtzFudSuwnBcgs2ubzd6F0SYsHGaJ + VmsVytnaDJt1nzp/fpFc6M5323NL0UKtogMWs/k8eI63cpxet3ypaXBr9e2TM51fCd46f8/y + mf6EMxcSlOdkJxktfKETz9Rh8WVpUo/d5G9LlFiKMxINtZiLihMBqPKXbNACAAA= +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Thu, 24 Oct 2013 21:39:18 -0000 + +This can substantially reduce the cost of notmuch new in some +situations, such as when the file system cache is cold or when the +Maildir is on NFS. +--- + +This should fix the problem with directories containing symlinks to +other directories, but no actual sub-directories. + + notmuch-new.c | 29 +++++++++++++++++++++++++++++ + 1 file changed, 29 insertions(+) + +diff --git a/notmuch-new.c b/notmuch-new.c +index faa33f1..ba05cb4 100644 +--- a/notmuch-new.c ++++ b/notmuch-new.c +@@ -323,6 +323,35 @@ add_files (notmuch_database_t *notmuch, + } + db_mtime = directory ? notmuch_directory_get_mtime (directory) : 0; + ++ /* If the directory is unchanged from our last scan and has no ++ * sub-directories, then return without scanning it at all. In ++ * some situations, skipping the scan can substantially reduce the ++ * cost of notmuch new, especially since the huge numbers of files ++ * in Maildirs make scans expensive, but all files live in leaf ++ * directories. ++ * ++ * To check for sub-directories, we borrow a trick from find, ++ * kpathsea, and many other UNIX tools: since a directory's link ++ * count is the number of sub-directories (specifically, their ++ * '..' entries) plus 2 (the link from the parent and the link for ++ * '.'). This check is safe even on weird file systems, since ++ * file systems that can't compute this will return 0 or 1. This ++ * is safe even on *really* weird file systems like HFS+ that ++ * mistakenly return the total number of directory entries, since ++ * that only inflates the count beyond 2. ++ */ ++ if (directory && fs_mtime == db_mtime && st.st_nlink == 2) { ++ /* There's one catch: pass 1 below considers symlinks to ++ * directories to be directories, but these don't increase the ++ * file system link count. So, only bail early if the ++ * database agrees that there are no sub-directories. */ ++ db_subdirs = notmuch_directory_get_child_directories (directory); ++ if (!notmuch_filenames_valid (db_subdirs)) ++ goto DONE; ++ notmuch_filenames_destroy (db_subdirs); ++ db_subdirs = NULL; ++ } ++ + /* If the database knows about this directory, then we sort based + * on strcmp to match the database sorting. Otherwise, we can do + * inode-based sorting for faster filesystem operation. */ +-- +1.8.4.rc3 +