Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S975171AbdDXQ46 (ORCPT ); Mon, 24 Apr 2017 12:56:58 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:35519 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S975152AbdDXQ4z (ORCPT ); Mon, 24 Apr 2017 12:56:55 -0400 MIME-Version: 1.0 In-Reply-To: <20170424160841.GS12323@arm.com> References: <1493035176-3633-1-git-send-email-gakula@caviumnetworks.com> <20170424160841.GS12323@arm.com> From: Sunil Kovvuri Date: Mon, 24 Apr 2017 22:26:53 +0530 Message-ID: Subject: Re: [PATCH] iommu/arm-smmu-v3: Increase SMMU CMD queue poll timeout To: Will Deacon Cc: Geetha sowjanya , "Goutham, Sunil" , Catalin Marinas , LKML , iommu@lists.linux-foundation.org, Geetha , Robin Murphy , LAKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2122 Lines: 62 On Mon, Apr 24, 2017 at 9:38 PM, Will Deacon wrote: > On Mon, Apr 24, 2017 at 05:29:36PM +0530, Geetha sowjanya wrote: >> From: Geetha >> >> When large memory is being unmapped, huge no of tlb invalidation cmds are >> submitted followed by a SYNC command. This sometimes hits CMD queue full and >> poll on queue drain is being timedout throwing error message 'CMD_SYNC timeout'. >> >> Although there is no functional issue, error message confuses user. Hence increased >> poll timeout to 500us > > Hmm, what are you doing to unmap that much? Is this VFIO teardown? Do you > have 7c6d90e2bb1a ("iommu/io-pgtable-arm: Fix iova_to_phys for block > entries") applied? Yes it's VFIO teardown and again yes the above fix is applied. But i didn't get how above fix is related. TLB invalidation commands are submitted at 'arm_smmu_tlb_inv_range_nosync()' and it's a loop over granule size. 1357 do { 1358 arm_smmu_cmdq_issue_cmd(smmu, &cmd); 1359 cmd.tlbi.addr += granule; 1360 } while (size -= granule); So if invalidation size is big then huge no of invalidation commands will be submitted irrespective of fix that you pointed above, right ? Thanks, Sunil. > > Will > >> >> Signed-off-by: Geetha >> --- >> drivers/iommu/arm-smmu-v3.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c >> index 591bb96..1dcd154 100644 >> --- a/drivers/iommu/arm-smmu-v3.c >> +++ b/drivers/iommu/arm-smmu-v3.c >> @@ -407,7 +407,7 @@ >> #define PRIQ_1_ADDR_MASK 0xfffffffffffffUL >> >> /* High-level queue structures */ >> -#define ARM_SMMU_POLL_TIMEOUT_US 100 >> +#define ARM_SMMU_POLL_TIMEOUT_US 500 >> >> #define MSI_IOVA_BASE 0x8000000 >> #define MSI_IOVA_LENGTH 0x100000 >> -- >> 1.9.1 >> > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel