Revision 6e474083f3daf3a3546737f5d7d502ad12eb257c authored by Wei Xu on 01 December 2017, 10:10:36 UTC, committed by David S. Miller on 03 December 2017, 02:31:03 UTC
Matthew found a roughly 40% tcp throughput regression with commit
c67df11f(vhost_net: try batch dequing from skb array) as discussed
in the following thread:
https://www.mail-archive.com/netdev@vger.kernel.org/msg187936.html

Eventually we figured out that it was a skb leak in handle_rx()
when sending packets to the VM. This usually happens when a guest
can not drain out vq as fast as vhost fills in, afterwards it sets
off the traffic jam and leaks skb(s) which occurs as no headcount
to send on the vq from vhost side.

This can be avoided by making sure we have got enough headcount
before actually consuming a skb from the batched rx array while
transmitting, which is simply done by moving checking the zero
headcount a bit ahead.

Signed-off-by: Wei Xu <wexu@redhat.com>
Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent fa935ca
Raw File
arm-smmu-regs.h
/*
 * IOMMU API for ARM architected SMMU implementations.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright (C) 2013 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#ifndef _ARM_SMMU_REGS_H
#define _ARM_SMMU_REGS_H

/* Configuration registers */
#define ARM_SMMU_GR0_sCR0		0x0
#define sCR0_CLIENTPD			(1 << 0)
#define sCR0_GFRE			(1 << 1)
#define sCR0_GFIE			(1 << 2)
#define sCR0_EXIDENABLE			(1 << 3)
#define sCR0_GCFGFRE			(1 << 4)
#define sCR0_GCFGFIE			(1 << 5)
#define sCR0_USFCFG			(1 << 10)
#define sCR0_VMIDPNE			(1 << 11)
#define sCR0_PTM			(1 << 12)
#define sCR0_FB				(1 << 13)
#define sCR0_VMID16EN			(1 << 31)
#define sCR0_BSU_SHIFT			14
#define sCR0_BSU_MASK			0x3

/* Auxiliary Configuration register */
#define ARM_SMMU_GR0_sACR		0x10

/* Identification registers */
#define ARM_SMMU_GR0_ID0		0x20
#define ARM_SMMU_GR0_ID1		0x24
#define ARM_SMMU_GR0_ID2		0x28
#define ARM_SMMU_GR0_ID3		0x2c
#define ARM_SMMU_GR0_ID4		0x30
#define ARM_SMMU_GR0_ID5		0x34
#define ARM_SMMU_GR0_ID6		0x38
#define ARM_SMMU_GR0_ID7		0x3c
#define ARM_SMMU_GR0_sGFSR		0x48
#define ARM_SMMU_GR0_sGFSYNR0		0x50
#define ARM_SMMU_GR0_sGFSYNR1		0x54
#define ARM_SMMU_GR0_sGFSYNR2		0x58

#define ID0_S1TS			(1 << 30)
#define ID0_S2TS			(1 << 29)
#define ID0_NTS				(1 << 28)
#define ID0_SMS				(1 << 27)
#define ID0_ATOSNS			(1 << 26)
#define ID0_PTFS_NO_AARCH32		(1 << 25)
#define ID0_PTFS_NO_AARCH32S		(1 << 24)
#define ID0_CTTW			(1 << 14)
#define ID0_NUMIRPT_SHIFT		16
#define ID0_NUMIRPT_MASK		0xff
#define ID0_NUMSIDB_SHIFT		9
#define ID0_NUMSIDB_MASK		0xf
#define ID0_EXIDS			(1 << 8)
#define ID0_NUMSMRG_SHIFT		0
#define ID0_NUMSMRG_MASK		0xff

#define ID1_PAGESIZE			(1 << 31)
#define ID1_NUMPAGENDXB_SHIFT		28
#define ID1_NUMPAGENDXB_MASK		7
#define ID1_NUMS2CB_SHIFT		16
#define ID1_NUMS2CB_MASK		0xff
#define ID1_NUMCB_SHIFT			0
#define ID1_NUMCB_MASK			0xff

#define ID2_OAS_SHIFT			4
#define ID2_OAS_MASK			0xf
#define ID2_IAS_SHIFT			0
#define ID2_IAS_MASK			0xf
#define ID2_UBS_SHIFT			8
#define ID2_UBS_MASK			0xf
#define ID2_PTFS_4K			(1 << 12)
#define ID2_PTFS_16K			(1 << 13)
#define ID2_PTFS_64K			(1 << 14)
#define ID2_VMID16			(1 << 15)

#define ID7_MAJOR_SHIFT			4
#define ID7_MAJOR_MASK			0xf

/* Global TLB invalidation */
#define ARM_SMMU_GR0_TLBIVMID		0x64
#define ARM_SMMU_GR0_TLBIALLNSNH	0x68
#define ARM_SMMU_GR0_TLBIALLH		0x6c
#define ARM_SMMU_GR0_sTLBGSYNC		0x70
#define ARM_SMMU_GR0_sTLBGSTATUS	0x74
#define sTLBGSTATUS_GSACTIVE		(1 << 0)

/* Stream mapping registers */
#define ARM_SMMU_GR0_SMR(n)		(0x800 + ((n) << 2))
#define SMR_VALID			(1 << 31)
#define SMR_MASK_SHIFT			16
#define SMR_ID_SHIFT			0

#define ARM_SMMU_GR0_S2CR(n)		(0xc00 + ((n) << 2))
#define S2CR_CBNDX_SHIFT		0
#define S2CR_CBNDX_MASK			0xff
#define S2CR_EXIDVALID			(1 << 10)
#define S2CR_TYPE_SHIFT			16
#define S2CR_TYPE_MASK			0x3
enum arm_smmu_s2cr_type {
	S2CR_TYPE_TRANS,
	S2CR_TYPE_BYPASS,
	S2CR_TYPE_FAULT,
};

#define S2CR_PRIVCFG_SHIFT		24
#define S2CR_PRIVCFG_MASK		0x3
enum arm_smmu_s2cr_privcfg {
	S2CR_PRIVCFG_DEFAULT,
	S2CR_PRIVCFG_DIPAN,
	S2CR_PRIVCFG_UNPRIV,
	S2CR_PRIVCFG_PRIV,
};

/* Context bank attribute registers */
#define ARM_SMMU_GR1_CBAR(n)		(0x0 + ((n) << 2))
#define CBAR_VMID_SHIFT			0
#define CBAR_VMID_MASK			0xff
#define CBAR_S1_BPSHCFG_SHIFT		8
#define CBAR_S1_BPSHCFG_MASK		3
#define CBAR_S1_BPSHCFG_NSH		3
#define CBAR_S1_MEMATTR_SHIFT		12
#define CBAR_S1_MEMATTR_MASK		0xf
#define CBAR_S1_MEMATTR_WB		0xf
#define CBAR_TYPE_SHIFT			16
#define CBAR_TYPE_MASK			0x3
#define CBAR_TYPE_S2_TRANS		(0 << CBAR_TYPE_SHIFT)
#define CBAR_TYPE_S1_TRANS_S2_BYPASS	(1 << CBAR_TYPE_SHIFT)
#define CBAR_TYPE_S1_TRANS_S2_FAULT	(2 << CBAR_TYPE_SHIFT)
#define CBAR_TYPE_S1_TRANS_S2_TRANS	(3 << CBAR_TYPE_SHIFT)
#define CBAR_IRPTNDX_SHIFT		24
#define CBAR_IRPTNDX_MASK		0xff

#define ARM_SMMU_GR1_CBA2R(n)		(0x800 + ((n) << 2))
#define CBA2R_RW64_32BIT		(0 << 0)
#define CBA2R_RW64_64BIT		(1 << 0)
#define CBA2R_VMID_SHIFT		16
#define CBA2R_VMID_MASK			0xffff

#define ARM_SMMU_CB_SCTLR		0x0
#define ARM_SMMU_CB_ACTLR		0x4
#define ARM_SMMU_CB_RESUME		0x8
#define ARM_SMMU_CB_TTBCR2		0x10
#define ARM_SMMU_CB_TTBR0		0x20
#define ARM_SMMU_CB_TTBR1		0x28
#define ARM_SMMU_CB_TTBCR		0x30
#define ARM_SMMU_CB_CONTEXTIDR		0x34
#define ARM_SMMU_CB_S1_MAIR0		0x38
#define ARM_SMMU_CB_S1_MAIR1		0x3c
#define ARM_SMMU_CB_PAR			0x50
#define ARM_SMMU_CB_FSR			0x58
#define ARM_SMMU_CB_FAR			0x60
#define ARM_SMMU_CB_FSYNR0		0x68
#define ARM_SMMU_CB_S1_TLBIVA		0x600
#define ARM_SMMU_CB_S1_TLBIASID		0x610
#define ARM_SMMU_CB_S1_TLBIVAL		0x620
#define ARM_SMMU_CB_S2_TLBIIPAS2	0x630
#define ARM_SMMU_CB_S2_TLBIIPAS2L	0x638
#define ARM_SMMU_CB_TLBSYNC		0x7f0
#define ARM_SMMU_CB_TLBSTATUS		0x7f4
#define ARM_SMMU_CB_ATS1PR		0x800
#define ARM_SMMU_CB_ATSR		0x8f0

#define SCTLR_S1_ASIDPNE		(1 << 12)
#define SCTLR_CFCFG			(1 << 7)
#define SCTLR_CFIE			(1 << 6)
#define SCTLR_CFRE			(1 << 5)
#define SCTLR_E				(1 << 4)
#define SCTLR_AFE			(1 << 2)
#define SCTLR_TRE			(1 << 1)
#define SCTLR_M				(1 << 0)

#define CB_PAR_F			(1 << 0)

#define ATSR_ACTIVE			(1 << 0)

#define RESUME_RETRY			(0 << 0)
#define RESUME_TERMINATE		(1 << 0)

#define TTBCR2_SEP_SHIFT		15
#define TTBCR2_SEP_UPSTREAM		(0x7 << TTBCR2_SEP_SHIFT)
#define TTBCR2_AS			(1 << 4)

#define TTBRn_ASID_SHIFT		48

#define FSR_MULTI			(1 << 31)
#define FSR_SS				(1 << 30)
#define FSR_UUT				(1 << 8)
#define FSR_ASF				(1 << 7)
#define FSR_TLBLKF			(1 << 6)
#define FSR_TLBMCF			(1 << 5)
#define FSR_EF				(1 << 4)
#define FSR_PF				(1 << 3)
#define FSR_AFF				(1 << 2)
#define FSR_TF				(1 << 1)

#define FSR_IGN				(FSR_AFF | FSR_ASF | \
					 FSR_TLBMCF | FSR_TLBLKF)
#define FSR_FAULT			(FSR_MULTI | FSR_SS | FSR_UUT | \
					 FSR_EF | FSR_PF | FSR_TF | FSR_IGN)

#define FSYNR0_WNR			(1 << 4)

#endif /* _ARM_SMMU_REGS_H */
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