From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout4.samsung.com (mailout4.samsung.com [203.254.224.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 714801EB1AA for ; Sun, 14 Jun 2026 09:41:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781430087; cv=none; b=X0p+WdoZ9hwPq0TaXt3pojDysNKRVp0He9qvHDvgL3lniQhUTtcWGd63wRgZyvtUKznlqYJF+gtyl834qc1Sx6PxVZIOuDiNs2CVbJwpcXvQrrOcXfAmizomXNH/k5mGYyJgGt6uxSBeNCmNHjadyA1eMDL8hPrOY20qee/q7h4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781430087; c=relaxed/simple; bh=htRbPhnmI0Q7zbPGHmmpYE56eD5t0fPvtymFYGdYU6s=; h=From:To:Cc:In-Reply-To:Subject:Date:Message-ID:MIME-Version: Content-Type:References; b=mpWd4Ea2/L7N6nED5zVMI4iGpZd4KFhvQNcGLY7u8isDq0BsbvFJJa/0j7RFFiF8nctSk9ibZuO6LVBukprVwian85eIhM8GHcCxgPLfi6drLUbK24BxHq99yCe3zXECsBzirnAGki7yQLgmOqX4PguOYsPqAyNVuS/ceGQUTmM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=ACpzmtzP; arc=none smtp.client-ip=203.254.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="ACpzmtzP" Received: from epcas1p2.samsung.com (unknown [182.195.41.46]) by mailout4.samsung.com (KnoxPortal) with ESMTP id 20260614094117epoutp043fc6ef8a45ef1534f9a458276084cccf~46Tearn-42388423884epoutp040 for ; Sun, 14 Jun 2026 09:41:17 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout4.samsung.com 20260614094117epoutp043fc6ef8a45ef1534f9a458276084cccf~46Tearn-42388423884epoutp040 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1781430077; bh=c10yNbrFXneieObebopqp/M64tMqvfZfGb2DL9uARpU=; h=From:To:Cc:In-Reply-To:Subject:Date:References:From; b=ACpzmtzPo6vx5D8oo0J1Rsen72nmsVDCM/fg2P3+uVpqmpTsd08JZw9pRQzmu0nY4 QigRZL8mTcayAd9LEK4rAinqOEPMul1gMVUXWnSf6RO2oXM7j6eq77L3rhjNZEETBe j9wfQikFQaFD3n88CWgPv94Iz7CJU3oMKAk67yvM= Received: from epsnrtp02.localdomain (unknown [182.195.42.154]) by epcas1p3.samsung.com (KnoxPortal) with ESMTPS id 20260614094116epcas1p3e4df91a880840d7890a32249c04094dd~46TdXuXo40905809058epcas1p3q; Sun, 14 Jun 2026 09:41:16 +0000 (GMT) Received: from epcas1p1.samsung.com (unknown [182.195.38.119]) by epsnrtp02.localdomain (Postfix) with ESMTP id 4gdSth275lz2SSKX; Sun, 14 Jun 2026 09:41:16 +0000 (GMT) Received: from epsmtip2.samsung.com (unknown [182.195.34.31]) by epcas1p1.samsung.com (KnoxPortal) with ESMTPA id 20260614094114epcas1p1c29a2c017e9791fd43aeda4327663d7a~46Tb3Mc0e2304723047epcas1p18; Sun, 14 Jun 2026 09:41:14 +0000 (GMT) Received: from W11PB11713 (unknown [10.91.160.69]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260614094114epsmtip234d9e533518cdc49407ae4a83304adee~46TbyT6vY0889608896epsmtip2Y; Sun, 14 Jun 2026 09:41:14 +0000 (GMT) From: "Sungjong Seo" To: "'Yang Wen'" , Cc: , , , , , In-Reply-To: <20260613133856.238740-1-anmuxixixi@gmail.com> Subject: RE: [PATCH v2 0/1] exfat: reduce directory scans during file creation Date: Sun, 14 Jun 2026 18:41:14 +0900 Message-ID: <000001dcfbe1$f1341d10$d39c5730$@samsung.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQGbhcuwXyd99kU9K9PfQeBinsaqrQKSFDtBtqwjvUA= Content-Language: ko X-CMS-MailID: 20260614094114epcas1p1c29a2c017e9791fd43aeda4327663d7a X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 101P X-CPGSPASS: Y cpgsPolicy: CPGSC10-711,N X-CFilter-Loop: Reflected X-CMS-RootMailID: 20260613133917epcas1p183cb2d5b2c82fa1651a96364cd8efda8 References: <20260613133856.238740-1-anmuxixixi@gmail.com> > Creating files in a large exfat directory may require repeated linear > directory scans. > > After an empty-entry hint is used successfully, the remaining contiguous > empty entries are not retained for the next create operation. > This can cause subsequent operations to rediscover available directory > space. > > In a test creating 20,000 files with random names and sizes between 1 KiB > and 4 KiB in one directory, the elapsed time changed as follows: > > Before: 3879 seconds > After: 3050 seconds Hello, Yang Wen, As Namjae reviewed, we intentionally drop the dentry in LOOKUP_CREATE to maintain the case of newly created filenames. Therefore, when creating a new file, a brute-force search of the entire directory is required, and the hint value is naturally updated during this process. For this reason, I believe this current patch will not improve performance and is an unnecessary operation. Is there any performance gain with the current patch, excluding the dropped part? > > --- > > Changes since v1: > - Drop the LOOKUP_CREATE negative dentry change. > - Make exfat_cache_next_empty_entry() return void and skip caching if > exfat_chain_advance() fails. > > Yang Wen (1): > exfat: preserve the next empty-entry hint after allocation > > fs/exfat/namei.c | 39 +++++++++++++++++++++++++++++++++++++-- > 1 file changed, 37 insertions(+), 2 deletions(-) > > -- > 2.34.1