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{ "id": 23745, "url": "https://patchwork.libcamera.org/api/1.1/patches/23745/?format=api", "web_url": "https://patchwork.libcamera.org/patch/23745/", "project": { "id": 1, "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api", "name": "libcamera", "link_name": "libcamera", "list_id": "libcamera_core", "list_email": "libcamera-devel@lists.libcamera.org", "web_url": "", "scm_url": "", "webscm_url": "" }, "msgid": "<20250707075400.9079-3-stefan.klug@ideasonboard.com>", "date": "2025-07-07T07:53:36", "name": "[v2,2/5] libcamera: pipeline_handler: Allow to limit the number of queued requests", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": false, "hash": "505d59ec763cf91a4bfb2d8488b062e95ddc8c24", "submitter": { "id": 184, "url": "https://patchwork.libcamera.org/api/1.1/people/184/?format=api", "name": "Stefan Klug", "email": "stefan.klug@ideasonboard.com" }, "delegate": null, "mbox": "https://patchwork.libcamera.org/patch/23745/mbox/", "series": [ { "id": 5272, "url": "https://patchwork.libcamera.org/api/1.1/series/5272/?format=api", "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=5272", "date": "2025-07-07T07:53:34", "name": "rkisp1: Allow usage of more than 4 buffers", "version": 2, "mbox": "https://patchwork.libcamera.org/series/5272/mbox/" } ], "comments": "https://patchwork.libcamera.org/api/patches/23745/comments/", "check": "pending", "checks": "https://patchwork.libcamera.org/api/patches/23745/checks/", "tags": {}, "headers": { "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>", "X-Original-To": "parsemail@patchwork.libcamera.org", "Delivered-To": "parsemail@patchwork.libcamera.org", "Received": [ "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 46D48C3237\n\tfor <parsemail@patchwork.libcamera.org>;\n\tMon, 7 Jul 2025 07:54:24 +0000 (UTC)", "from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 50EBE68E83;\n\tMon, 7 Jul 2025 09:54:23 +0200 (CEST)", "from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 3BF7668E77\n\tfor <libcamera-devel@lists.libcamera.org>;\n\tMon, 7 Jul 2025 09:54:18 +0200 (CEST)", "from ideasonboard.com (unknown\n\t[IPv6:2a00:6020:448c:6c00:c79f:85df:e7f5:4c31])\n\tby perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 9C82C9CA;\n\tMon, 7 Jul 2025 09:53:51 +0200 (CEST)" ], "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"Hi54uGBD\"; dkim-atps=neutral", "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1751874831;\n\tbh=CHenzEB2uLrp8qlnX9B54j8HUaJQyD2xNOrdMXAZ+3s=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=Hi54uGBDobbzkZdV6uy1fSTI6/9yGsVqAMM1kSSm0+0xQclpR30ErPsLVdnZItQRq\n\txKJxz/Z9CqZQNjJa6LaqNzcCLcRsxvv5LtaCWuYlMoZwOijifuOERQ5GteKCsjHBt7\n\tPlkjtz5wOcdpACEFRJuOUwvN+Qz83SDa35/gTGn0=", "From": "Stefan Klug <stefan.klug@ideasonboard.com>", "To": "libcamera-devel@lists.libcamera.org", "Cc": "Stefan Klug <stefan.klug@ideasonboard.com>,\n\tKieran Bingham <kieran.bingham@ideasonboard.com>", "Subject": "[PATCH v2 2/5] libcamera: pipeline_handler: Allow to limit the\n\tnumber of queued requests", "Date": "Mon, 7 Jul 2025 09:53:36 +0200", "Message-ID": "<20250707075400.9079-3-stefan.klug@ideasonboard.com>", "X-Mailer": "git-send-email 2.48.1", "In-Reply-To": "<20250707075400.9079-1-stefan.klug@ideasonboard.com>", "References": "<20250707075400.9079-1-stefan.klug@ideasonboard.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-BeenThere": "libcamera-devel@lists.libcamera.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "<libcamera-devel.lists.libcamera.org>", "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>", "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>", "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>", "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>", "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>", "Errors-To": "libcamera-devel-bounces@lists.libcamera.org", "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>" }, "content": "Add a maxQueuedRequestsDevice constructor parameter to allow pipeline\nhandler classes to limit the maximum number of requests that get queued\nto the device in queueRequestDevice().\n\nThe default value is set to an arbitrary number of 32 which is big\nenough for all currently known use cases.\n\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\nSigned-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>\nSigned-off-by: Stefan Klug <stefan.klug@ideasonboard.com>\n\n---\n\nChanges in v2:\n- Moved the fix to properly handle the waitingRequests queue when\n stopping the device into this patch as they belong together\n- Added documentation for maxQueuedRequestsDevice_\n- Fixed an issue with doQueueRequests beeing() called recursively\n\nChanges in v1:\n- Used a const member variable to carry the maximum number of requests\n- Improved commit message\n- Added docs\n---\n include/libcamera/internal/pipeline_handler.h | 4 +-\n src/libcamera/pipeline_handler.cpp | 56 +++++++++++++++----\n 2 files changed, 48 insertions(+), 12 deletions(-)", "diff": "diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h\nindex be017ad47219..e89d6a33e398 100644\n--- a/include/libcamera/internal/pipeline_handler.h\n+++ b/include/libcamera/internal/pipeline_handler.h\n@@ -33,7 +33,8 @@ class PipelineHandler : public std::enable_shared_from_this<PipelineHandler>,\n \t\t\tpublic Object\n {\n public:\n-\tPipelineHandler(CameraManager *manager);\n+\tPipelineHandler(CameraManager *manager,\n+\t\t\tunsigned int maxQueuedRequestsDevice = 32);\n \tvirtual ~PipelineHandler();\n \n \tvirtual bool match(DeviceEnumerator *enumerator) = 0;\n@@ -80,6 +81,7 @@ protected:\n \tvirtual void releaseDevice(Camera *camera);\n \n \tCameraManager *manager_;\n+\tconst unsigned int maxQueuedRequestsDevice_;\n \n private:\n \tvoid unlockMediaDevices();\ndiff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp\nindex b50eda5e0f86..e8601be108f0 100644\n--- a/src/libcamera/pipeline_handler.cpp\n+++ b/src/libcamera/pipeline_handler.cpp\n@@ -62,13 +62,17 @@ LOG_DEFINE_CATEGORY(Pipeline)\n /**\n * \\brief Construct a PipelineHandler instance\n * \\param[in] manager The camera manager\n+ * \\param[in] maxQueuedRequestsDevice The maximum number of requests queued to\n+ * the device\n *\n * In order to honour the std::enable_shared_from_this<> contract,\n * PipelineHandler instances shall never be constructed manually, but always\n * through the PipelineHandlerFactoryBase::create() function.\n */\n-PipelineHandler::PipelineHandler(CameraManager *manager)\n-\t: manager_(manager), useCount_(0)\n+PipelineHandler::PipelineHandler(CameraManager *manager,\n+\t\t\t\t unsigned int maxQueuedRequestsDevice)\n+\t: manager_(manager), maxQueuedRequestsDevice_(maxQueuedRequestsDevice),\n+\t useCount_(0)\n {\n }\n \n@@ -360,20 +364,28 @@ void PipelineHandler::unlockMediaDevices()\n */\n void PipelineHandler::stop(Camera *camera)\n {\n+\t/*\n+\t * Take all waiting requests so that they are not requeued in response\n+\t * to completeRequest() being called inside stopDevice(). Cancel them\n+\t * after the device to keep them in order.\n+\t */\n+\tCamera::Private *data = camera->_d();\n+\tstd::queue<Request *> waitingRequests;\n+\twaitingRequests.swap(data->waitingRequests_);\n+\n \t/* Stop the pipeline handler and let the queued requests complete. */\n \tstopDevice(camera);\n \n-\tCamera::Private *data = camera->_d();\n-\n \t/* Cancel and signal as complete all waiting requests. */\n-\twhile (!data->waitingRequests_.empty()) {\n-\t\tRequest *request = data->waitingRequests_.front();\n-\t\tdata->waitingRequests_.pop();\n+\twhile (!waitingRequests.empty()) {\n+\t\tRequest *request = waitingRequests.front();\n+\t\twaitingRequests.pop();\n \t\tcancelRequest(request);\n \t}\n \n \t/* Make sure no requests are pending. */\n \tASSERT(data->queuedRequests_.empty());\n+\tASSERT(data->waitingRequests_.empty());\n \n \tdata->requestSequence_ = 0;\n }\n@@ -430,9 +442,9 @@ void PipelineHandler::registerRequest(Request *request)\n * requests which have to be prepared to make sure they are ready for being\n * queued to the pipeline handler.\n *\n- * The queue of waiting requests is iterated and all prepared requests are\n- * passed to the pipeline handler in the same order they have been queued by\n- * calling this function.\n+ * The queue of waiting requests is iterated and up to \\a\n+ * maxQueuedRequestsDevice_ prepared requests are passed to the pipeline handler\n+ * in the same order they have been queued by calling this function.\n *\n * If a Request fails during the preparation phase or if the pipeline handler\n * fails in queuing the request to the hardware the request is cancelled.\n@@ -487,12 +499,19 @@ void PipelineHandler::doQueueRequests(Camera *camera)\n {\n \tCamera::Private *data = camera->_d();\n \twhile (!data->waitingRequests_.empty()) {\n+\t\tif (data->queuedRequests_.size() == maxQueuedRequestsDevice_)\n+\t\t\tbreak;\n+\n \t\tRequest *request = data->waitingRequests_.front();\n \t\tif (!request->_d()->prepared_)\n \t\t\tbreak;\n \n-\t\tdoQueueRequest(request);\n+\t\t/*\n+\t\t * Pop the request first, in case doQueueRequests() is called\n+\t\t * recursively from within doQueueRequest()\n+\t\t */\n \t\tdata->waitingRequests_.pop();\n+\t\tdoQueueRequest(request);\n \t}\n }\n \n@@ -568,6 +587,9 @@ void PipelineHandler::completeRequest(Request *request)\n \t\tdata->queuedRequests_.pop_front();\n \t\tcamera->requestComplete(req);\n \t}\n+\n+\t/* Allow any waiting requests to be queued to the pipeline. */\n+\tdoQueueRequests(camera);\n }\n \n /**\n@@ -768,6 +790,18 @@ void PipelineHandler::disconnect()\n * constant for the whole lifetime of the pipeline handler.\n */\n \n+/**\n+ * \\var PipelineHandler::maxQueuedRequestsDevice_\n+ * \\brief The maximum number of requests the pipeline handler shall queue to the\n+ * device\n+ *\n+ * Some pipeline handlers do not work efficiently with too many requests queued\n+ * into the device. Still it is beneficial for the application to circulate more\n+ * than the minimum number of buffers. This variable limits the number of\n+ * requests that get queued to the device at once. The rest is kept in a\n+ * a waiting queue.\n+ */\n+\n /**\n * \\fn PipelineHandler::name()\n * \\brief Retrieve the pipeline handler name\n", "prefixes": [ "v2", "2/5" ] }