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From: Haren Myneni <haren@linux.ibm.com>
To: mpe@ellerman.id.au
Cc: hch@infradead.org, mikey@neuling.org, npiggin@gmail.com,
	herbert@gondor.apana.org.au, linuxppc-dev@lists.ozlabs.org,
	devicetree@vger.kernel.org, sukadev@linux.vnet.ibm.com
Subject: [PATCH V2 12/13] powerpc/vas: Display process stuck message
Date: Sun, 08 Dec 2019 19:36:42 -0800	[thread overview]
Message-ID: <1575862602.16318.30.camel@hbabu-laptop> (raw)
In-Reply-To: <1575861522.16318.9.camel@hbabu-laptop>


Process can not close send window until all requests are processed.
Means wait until window state is not busy and send credits are
returned. Display debug message in case taking longer to close the
window.

Signed-off-by: Haren Myneni <haren@us.ibm.com>
---
 arch/powerpc/platforms/powernv/vas-window.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 27848d3..578f144 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -1176,6 +1176,7 @@ static void poll_window_credits(struct vas_window *window)
 {
 	u64 val;
 	int creds, mode;
+	int count = 0;
 
 	val = read_hvwc_reg(window, VREG(WINCTL));
 	if (window->tx_win)
@@ -1194,10 +1195,25 @@ static void poll_window_credits(struct vas_window *window)
 		creds = GET_FIELD(VAS_LRX_WCRED, val);
 	}
 
+	/*
+	 * Takes around few microseconds to complete all pending requests
+	 * and return credits.
+	 * TODO: Issue CRB Kill to stop all pending requests. Need only
+	 *       if there is a bug in NX or fault handling in kernel.
+	 */
 	if (creds < window->wcreds_max) {
 		val = 0;
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		schedule_timeout(msecs_to_jiffies(10));
+		count++;
+		/*
+		 * Process can not close send window until all credits are
+		 * returned.
+		 */
+		if (!(count % 10000))
+			pr_debug("%s() pid %d stuck? retries %d\n", __func__,
+				vas_window_pid(window), count);
+
 		goto retry;
 	}
 }
@@ -1211,6 +1227,7 @@ static void poll_window_busy_state(struct vas_window *window)
 {
 	int busy;
 	u64 val;
+	int count = 0;
 
 retry:
 	val = read_hvwc_reg(window, VREG(WIN_STATUS));
@@ -1219,6 +1236,15 @@ static void poll_window_busy_state(struct vas_window *window)
 		val = 0;
 		set_current_state(TASK_UNINTERRUPTIBLE);
 		schedule_timeout(msecs_to_jiffies(5));
+		count++;
+		/*
+		 * Takes around 5 microseconds to process all pending
+		 * requests.
+		 */
+		if (!(count % 10000))
+			pr_debug("%s() pid %d stuck? retries %d\n", __func__,
+				vas_window_pid(window), count);
+
 		goto retry;
 	}
 }
-- 
1.8.3.1




  parent reply	other threads:[~2019-12-09  3:38 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-09  3:18 [PATCH V2 00/13] powerpc/vas: Page fault handling for user space NX requests Haren Myneni
2019-12-09  3:26 ` [PATCH V2 01/13] powerpc/vas: Describe vas-port and interrupts properties Haren Myneni
2019-12-09  3:27 ` [PATCH V2 02/13] powerpc/vas: Define nx_fault_stamp in coprocessor_request_block Haren Myneni
2019-12-09  3:29 ` [PATCH V2 03/13] powerpc/vas: Read interrupts and vas-port device tree properties Haren Myneni
2019-12-09  3:30 ` [PATCH V2 04/13] powerpc/vas: Setup fault window per VAS instance Haren Myneni
2019-12-12 12:55   ` Christoph Hellwig
2019-12-09  3:31 ` [PATCH V2 05/13] powerpc/vas: Setup thread IRQ handler " Haren Myneni
2019-12-12 12:59   ` Christoph Hellwig
2019-12-09  3:32 ` [PATCH V2 06/13] powerpc/vas: Register NX with fault window ID and IRQ port value Haren Myneni
2019-12-09  3:32 ` [PATCH V2 07/13] powerpc/vas: Take reference to PID and mm for user space windows Haren Myneni
2019-12-12 13:02   ` Christoph Hellwig
2019-12-17  5:35     ` Haren Myneni
2019-12-09  3:33 ` [PATCH V2 08/13] powerpc/vas: Update CSB and notify process for fault CRBs Haren Myneni
2019-12-12 13:07   ` Christoph Hellwig
2019-12-09  3:34 ` [PATCH V2 09/13] powerpc/vas: Print CRB and FIFO values Haren Myneni
2019-12-09  3:34 ` [PATCH V2 10/13] powerpc/vas: Do not use default credits for receive window Haren Myneni
2019-12-09  3:35 ` [PATCH V2 11/13] powerpc/vas: Return credits after handling fault Haren Myneni
2019-12-09  3:36 ` Haren Myneni [this message]
2019-12-09  3:37 ` [PATCH V2 13/13] powerpc/vas: Free send window in VAS instance after credits returned Haren Myneni
2019-12-09  5:37 ` [PATCH V2 00/13] powerpc/vas: Page fault handling for user space NX requests Christophe Leroy
2019-12-09  8:38   ` Segher Boessenkool
2019-12-12  5:05     ` Haren Myneni
2019-12-12  5:38 ` Haren Myneni

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