From: Sebastian Ott <sebott@linux.vnet.ibm.com>
Subject: s390/pci: handle insufficient resources during dma tlb flush
Patch-mainline: v4.15-rc7
Git-commit: a5f1005517534aeb1fac20180badfbf0896c183c
References: bnc#1072915, LTC#163393
Description: s390/pci: improve lazy IOTLB flushing mode
Symptom: Some PCI workloads don't reach full
performance potential.
Problem: Even with lazy IOTLB flushing it is done
more often than needed.
Solution: Improve that and be as lazy as possible.
Reproduction: -
Upstream-Description:
s390/pci: handle insufficient resources during dma tlb flush
In a virtualized setup lazy flushing can lead to the hypervisor
running out of resources when lots of guest pages need to be
pinned. In this situation simply trigger a global flush to give
the hypervisor a chance to free some of these resources.
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
arch/s390/pci/pci_dma.c | 21 +++++++++++++++++++--
arch/s390/pci/pci_insn.c | 3 +++
2 files changed, 22 insertions(+), 2 deletions(-)
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -178,6 +178,9 @@ out_unlock:
static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
size_t size, int flags)
{
+ unsigned long irqflags;
+ int ret;
+
/*
* With zdev->tlb_refresh == 0, rpcit is not required to establish new
* translations when previously invalid translation-table entries are
@@ -193,8 +196,22 @@ static int __dma_purge_tlb(struct zpci_d
return 0;
}
- return zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
- PAGE_ALIGN(size));
+ ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
+ PAGE_ALIGN(size));
+ if (ret == -ENOMEM && !s390_iommu_strict) {
+ /* enable the hypervisor to free some resources */
+ if (zpci_refresh_global(zdev))
+ goto out;
+
+ spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);
+ bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
+ zdev->lazy_bitmap, zdev->iommu_pages);
+ bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
+ spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);
+ ret = 0;
+ }
+out:
+ return ret;
}
static int dma_update_trans(struct zpci_dev *zdev, unsigned long pa,
--- a/arch/s390/pci/pci_insn.c
+++ b/arch/s390/pci/pci_insn.c
@@ -87,6 +87,9 @@ int zpci_refresh_trans(u64 fn, u64 addr,
if (cc)
zpci_err_insn(cc, status, addr, range);
+ if (cc == 1 && (status == 4 || status == 16))
+ return -ENOMEM;
+
return (cc) ? -EIO : 0;
}