clocksource: Limit number of CPUs checked for clock synchronization

[linux-2.6-microblaze.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 7866cc1..9ec9ea1 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -581,6 +581,22 @@
                        loops can be debugged more effectively on production
                        systems.
 
+       clocksource.max_cswd_read_retries= [KNL]
+                       Number of clocksource_watchdog() retries due to
+                       external delays before the clock will be marked
+                       unstable.  Defaults to three retries, that is,
+                       four attempts to read the clock under test.
+
+       clocksource.verify_n_cpus= [KNL]
+                       Limit the number of CPUs checked for clocksources
+                       marked with CLOCK_SOURCE_VERIFY_PERCPU that
+                       are marked unstable due to excessive skew.
+                       A negative value says to check all CPUs, while
+                       zero says not to check any.  Values larger than
+                       nr_cpu_ids are silently truncated to nr_cpu_ids.
+                       The actual CPUs are chosen randomly, with
+                       no replacement if the same CPU is chosen twice.
+
        clearcpuid=BITNUM[,BITNUM...] [X86]
                        Disable CPUID feature X for the kernel. See
                        arch/x86/include/asm/cpufeatures.h for the valid bit
@@ -1469,6 +1485,12 @@
                        Don't use this when you are not running on the
                        android emulator
 
+       gpio-mockup.gpio_mockup_ranges
+                       [HW] Sets the ranges of gpiochip of for this device.
+                       Format: <start1>,<end1>,<start2>,<end2>...
+       gpio-mockup.gpio_mockup_named_lines
+                       [HW] Let the driver know GPIO lines should be named.
+
        gpt             [EFI] Forces disk with valid GPT signature but
                        invalid Protective MBR to be treated as GPT. If the
                        primary GPT is corrupted, it enables the backup/alternate
@@ -1492,10 +1514,6 @@
                        Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
                        Default: 1024
 
-       gpio-mockup.gpio_mockup_ranges
-                       [HW] Sets the ranges of gpiochip of for this device.
-                       Format: <start1>,<end1>,<start2>,<end2>...
-
        hardlockup_all_cpu_backtrace=
                        [KNL] Should the hard-lockup detector generate
                        backtraces on all cpus.
@@ -1889,13 +1907,6 @@
                        bypassed by not enabling DMAR with this option. In
                        this case, gfx device will use physical address for
                        DMA.
-               forcedac [X86-64]
-                       With this option iommu will not optimize to look
-                       for io virtual address below 32-bit forcing dual
-                       address cycle on pci bus for cards supporting greater
-                       than 32-bit addressing. The default is to look
-                       for translation below 32-bit and if not available
-                       then look in the higher range.
                strict [Default Off]
                        With this option on every unmap_single operation will
                        result in a hardware IOTLB flush operation as opposed
@@ -1984,6 +1995,14 @@
                nobypass        [PPC/POWERNV]
                        Disable IOMMU bypass, using IOMMU for PCI devices.
 
+       iommu.forcedac= [ARM64, X86] Control IOVA allocation for PCI devices.
+                       Format: { "0" | "1" }
+                       0 - Try to allocate a 32-bit DMA address first, before
+                         falling back to the full range if needed.
+                       1 - Allocate directly from the full usable range,
+                         forcing Dual Address Cycle for PCI cards supporting
+                         greater than 32-bit addressing.
+
        iommu.strict=   [ARM64] Configure TLB invalidation behaviour
                        Format: { "0" | "1" }
                        0 - Lazy mode.
@@ -2830,7 +2849,7 @@
                        Note that even when enabled, there are a few cases where
                        the feature is not effective.
 
-       memtest=        [KNL,X86,ARM,PPC] Enable memtest
+       memtest=        [KNL,X86,ARM,PPC,RISCV] Enable memtest
                        Format: <integer>
                        default : 0 <disable>
                        Specifies the number of memtest passes to be
@@ -3279,6 +3298,8 @@
 
        nohugeiomap     [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
 
+       nohugevmalloc   [PPC] Disable kernel huge vmalloc mappings.
+
        nosmt           [KNL,S390] Disable symmetric multithreading (SMT).
                        Equivalent to smt=1.