Linux-NVME Archive on lore.kernel.org
 help / color / Atom feed
From: Keith Busch <kbusch@kernel.org>
To: linux-nvme@lists.infradead.org, hch@lst.de, sagi@grimberg.me
Cc: Keith Busch <kbusch@kernel.org>,
	bigeasy@linutronix.de, helgaas@kernel.org, ming.lei@redhat.com
Subject: [PATCH 2/4] nvme/pci: Mask legacy and MSI in threaded handler
Date: Thu, 28 Nov 2019 02:58:22 +0900
Message-ID: <20191127175824.1929-3-kbusch@kernel.org> (raw)
In-Reply-To: <20191127175824.1929-1-kbusch@kernel.org>

Local interrupts are re-enabled when the nvme irq thread is
woken. Subsequent MSI or a level triggered legacy interrupts may restart
the nvme irq check while the thread handler is running. This unnecessarily
spends CPU cycles and potentially triggers spurious interrupt detection,
disabling our NVMe irq.

Use the NVMe interrupt mask/clear registers to disable controller
interrupts while the nvme bottom half processes completions.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/pci.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 9d307593b94f..c5b837cba730 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1048,6 +1048,28 @@ static irqreturn_t nvme_irq_check(int irq, void *data)
 	return IRQ_NONE;
 }
 
+static irqreturn_t nvme_irq_thread_msi(int irq, void *data)
+{
+	struct nvme_queue *nvmeq = data;
+	struct nvme_dev *dev = nvmeq->dev;
+
+	nvme_irq(irq, data);
+	writel(1 << nvmeq->cq_vector, dev->bar + NVME_REG_INTMC);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t nvme_irq_check_msi(int irq, void *data)
+{
+	struct nvme_queue *nvmeq = data;
+	struct nvme_dev *dev = nvmeq->dev;
+
+	if (nvme_cqe_pending(nvmeq)) {
+		writel(1 << nvmeq->cq_vector, dev->bar + NVME_REG_INTMS);
+		return IRQ_WAKE_THREAD;
+	}
+	return IRQ_NONE;
+}
+
 /*
  * Poll for completions any queue, including those not dedicated to polling.
  * Can be called from any context.
@@ -1502,6 +1524,11 @@ static int queue_request_irq(struct nvme_queue *nvmeq)
 	int nr = nvmeq->dev->ctrl.instance;
 
 	if (use_threaded_interrupts) {
+		/* MSI and Legacy use the same NVMe IRQ masking */
+		if (!pdev->msix_enabled)
+			return pci_request_irq(pdev, nvmeq->cq_vector,
+				nvme_irq_check_msi, nvme_irq_thread_msi,
+				nvmeq, "nvme%dq%d", nr, nvmeq->qid);
 		return pci_request_irq(pdev, nvmeq->cq_vector, nvme_irq_check,
 				nvme_irq, nvmeq, "nvme%dq%d", nr, nvmeq->qid);
 	} else {
-- 
2.21.0


_______________________________________________
linux-nvme mailing list
linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme

  parent reply index

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-27 17:58 [PATCH 0/4] nvme: Threaded interrupt handling improvements Keith Busch
2019-11-27 17:58 ` [PATCH 1/4] PCI/MSI: Export __pci_msix_desc_mask_irq Keith Busch
2019-11-28  2:42   ` Sagi Grimberg
2019-11-28  3:41     ` Keith Busch
2019-11-28  7:17   ` Christoph Hellwig
2019-11-27 17:58 ` Keith Busch [this message]
2019-11-28  3:39   ` [PATCH 2/4] nvme/pci: Mask legacy and MSI in threaded handler Ming Lei
2019-11-28  3:48     ` Keith Busch
2019-11-28  3:58       ` Ming Lei
2019-11-28  4:14         ` Keith Busch
2019-11-28  8:41           ` Ming Lei
2019-11-27 17:58 ` [PATCH 3/4] nvme/pci: Mask MSIx interrupts for threaded handling Keith Busch
2019-11-28  7:19   ` Christoph Hellwig
2019-11-27 17:58 ` [PATCH 4/4] nvme/pci: Spin threaded interrupt completions Keith Busch
2019-11-28  2:46   ` Sagi Grimberg
2019-11-28  3:28     ` Keith Busch
2019-11-28  3:51       ` Ming Lei
2019-11-28  3:58         ` Keith Busch
2019-11-28  7:22   ` Christoph Hellwig
2019-11-29  9:13   ` Sebastian Andrzej Siewior
2019-11-30 18:10     ` Keith Busch
2019-12-02  1:10       ` Ming Lei
2019-12-02  1:30         ` Keith Busch
2019-12-02 16:51       ` Sebastian Andrzej Siewior
2019-11-28  7:50 ` [PATCH 0/4] nvme: Threaded interrupt handling improvements Christoph Hellwig
2019-11-28 17:59   ` Keith Busch
2019-11-29  8:30     ` Christoph Hellwig
2019-11-29  9:46 ` Sebastian Andrzej Siewior
2019-11-29 16:27   ` Keith Busch
2019-11-29 17:05     ` Sebastian Andrzej Siewior
2019-11-30 17:02       ` Keith Busch
2019-12-02 17:05         ` Sebastian Andrzej Siewior
2019-12-02 17:12           ` Christoph Hellwig
2019-12-02 18:06             ` Keith Busch
2019-12-03  7:40               ` Christoph Hellwig
2019-12-02 19:57             ` Sebastian Andrzej Siewior
2019-12-03  7:42               ` Christoph Hellwig

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191127175824.1929-3-kbusch@kernel.org \
    --to=kbusch@kernel.org \
    --cc=bigeasy@linutronix.de \
    --cc=hch@lst.de \
    --cc=helgaas@kernel.org \
    --cc=linux-nvme@lists.infradead.org \
    --cc=ming.lei@redhat.com \
    --cc=sagi@grimberg.me \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-NVME Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-nvme/0 linux-nvme/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-nvme linux-nvme/ https://lore.kernel.org/linux-nvme \
		linux-nvme@lists.infradead.org
	public-inbox-index linux-nvme

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-nvme


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git