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| author |   Jiang Biao <benbjiang@tencent.com> | 2020-08-24 13:20:25 +0800 |
|---|---|---|
| committer |   Bjorn Helgaas <bhelgaas@google.com> | 2020-09-17 12:21:46 -0500 |
| commit | 2ce02a864ac1a2bf99baeb20d38100d2cc413ac2 (patch) | |
| tree | c7215e9b59586a26ff2b58f754a0fbfe0af87363 /drivers/pci/pci-sysfs.c | |
| parent | PCI/ACPI: Tone down missing MCFG message (diff) | |
| download | linux-dev-2ce02a864ac1a2bf99baeb20d38100d2cc413ac2.tar.xz linux-dev-2ce02a864ac1a2bf99baeb20d38100d2cc413ac2.zip | |
PCI: Add schedule point in pci_read_config()
The PCI sysfs "config" file allows large reads, and the resulting PCI
config reads can take several milliseconds to complete. Testing with the
cyclictest [1] benchmark showed 5ms+ latencies.
Add a schedule point in pci_read_config() to reduce the maximum latency.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/clrkwllms/rt-tests.git/
[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20200824052025.48362-1-benbjiang@tencent.com
Reported-by: Bin Lai <robinlai@tencent.com>
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci/pci-sysfs.c')
| -rw-r--r-- | drivers/pci/pci-sysfs.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 6d78df981d41..3b9f63d3cad6 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -708,6 +708,7 @@ static ssize_t pci_read_config(struct file *filp, struct kobject *kobj, data[off - init_off + 3] = (val >> 24) & 0xff; off += 4; size -= 4; + cond_resched(); } if (size >= 2) { |