From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3B63F23AB86; Thu, 3 Jul 2025 15:05:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751555113; cv=none; b=s73BUvqAfZsevGQO/+KZ3Pd8NXER6glrPX4UMYLHTmG84QAvGa/91gzoUAYjI8LJ6DWOp7R0hmQdXwMA8mDGfrw4j9Fuo4uB8IywCDQywDVh9kJkNHvEdsaLmUFvsCy9jh8QuPm6QuXQrMQy0mypim2+lhDoGvPPsMaRbp63jaI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751555113; c=relaxed/simple; bh=vly1ByKcexcVFZ5TE+prqGIL3Nwp2vQ8lo8dCt5Q3Ds=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XVY5PQXDFnCTXvN1/JDYGrFL5iEgcOkJRMtVxjziUSdZxbZEDSYcaBswBKwVskJBeBfwLAScQtsa/BVny5X+bWQh1U6+eJReA4Oe+9QpH/Q4AfIuqrnR13KlsNFdJOhWS8LlCS44/U9rEPrtjKW9Fh7I18h55H+ytbNlK1xFNJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rFELMcOQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rFELMcOQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F8E4C4CEE3; Thu, 3 Jul 2025 15:05:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751555113; bh=vly1ByKcexcVFZ5TE+prqGIL3Nwp2vQ8lo8dCt5Q3Ds=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rFELMcOQzFIs+7WEg+vdigvpKntt9FQnM5U23ypQ4pBpn4AxZ2cbatrD+khWRuzN8 LYLrLHPz4Cg1oiwQfHCqN7qMNXX0Twuv6I82xfTXwfZcDgoISRYlyHoCePQ/AgzaXG sWrA5+B+oJ42VuoKpH7thpJxaps4dRo/IbqarXS0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuan-Wei Chiu , Robert Pang , Coly Li , "Ching-Chun (Jim) Huang" , Kent Overstreet , Andrew Morton Subject: [PATCH 6.15 179/263] bcache: remove unnecessary select MIN_HEAP Date: Thu, 3 Jul 2025 16:41:39 +0200 Message-ID: <20250703144011.522664477@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250703144004.276210867@linuxfoundation.org> References: <20250703144004.276210867@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuan-Wei Chiu commit 95b2e31e1752494d477c5da89d6789f769b0d67b upstream. After reverting the transition to the generic min heap library, bcache no longer depends on MIN_HEAP. The select entry can be removed to reduce code size and shrink the kernel's attack surface. This change effectively reverts the bcache-related part of commit 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions"). This is part of a series of changes to address a performance regression caused by the use of the generic min_heap implementation. As reported by Robert, bcache now suffers from latency spikes, with P100 (max) latency increasing from 600 ms to 2.4 seconds every 5 minutes. These regressions degrade bcache's effectiveness as a low-latency cache layer and lead to frequent timeouts and application stalls in production environments. Link: https://lore.kernel.org/lkml/CAJhEC05+0S69z+3+FB2Cd0hD+pCRyWTKLEOsc8BOmH73p1m+KQ@mail.gmail.com Link: https://lkml.kernel.org/r/20250614202353.1632957-4-visitorckw@gmail.com Fixes: 866898efbb25 ("bcache: remove heap-related macros and switch to generic min_heap") Fixes: 92a8b224b833 ("lib/min_heap: introduce non-inline versions of min heap API functions") Signed-off-by: Kuan-Wei Chiu Reported-by: Robert Pang Closes: https://lore.kernel.org/linux-bcache/CAJhEC06F_AtrPgw2-7CvCqZgeStgCtitbD-ryuPpXQA-JG5XXw@mail.gmail.com Acked-by: Coly Li Cc: Ching-Chun (Jim) Huang Cc: Kent Overstreet Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- drivers/md/bcache/Kconfig | 1 - 1 file changed, 1 deletion(-) --- a/drivers/md/bcache/Kconfig +++ b/drivers/md/bcache/Kconfig @@ -5,7 +5,6 @@ config BCACHE select BLOCK_HOLDER_DEPRECATED if SYSFS select CRC64 select CLOSURES - select MIN_HEAP help Allows a block device to be used as cache for other devices; uses a btree for indexing and the layout is optimized for SSDs.