diff options
author | David S. Miller | 2018-02-19 18:46:11 -0500 |
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committer | David S. Miller | 2018-02-19 18:46:11 -0500 |
commit | f5c0c6f4299f870f074235fbf552ecf957fc249c (patch) | |
tree | 6b46b9c0b271185b6f98fab350c3891042e729b1 /Documentation | |
parent | 26736a08ee0fb89a4f09bfb2c9f0805028ff63aa (diff) | |
parent | 79c0ef3e85c015b0921a8fd5dd539d1480e9cd6c (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/ABI/testing/sysfs-devices-platform-dock | 39 | ||||
-rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 77 | ||||
-rw-r--r-- | Documentation/ABI/testing/sysfs-platform-dptf | 40 | ||||
-rw-r--r-- | Documentation/atomic_bitops.txt | 7 | ||||
-rw-r--r-- | Documentation/devicetree/bindings/power/mti,mips-cpc.txt | 8 | ||||
-rw-r--r-- | Documentation/features/sched/membarrier-sync-core/arch-support.txt | 62 | ||||
-rw-r--r-- | Documentation/locking/mutex-design.txt | 49 | ||||
-rw-r--r-- | Documentation/networking/segmentation-offloads.txt | 38 |
8 files changed, 281 insertions, 39 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-platform-dock b/Documentation/ABI/testing/sysfs-devices-platform-dock new file mode 100644 index 000000000000..1d8c18f905c7 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-platform-dock @@ -0,0 +1,39 @@ +What: /sys/devices/platform/dock.N/docked +Date: Dec, 2006 +KernelVersion: 2.6.19 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Value 1 or 0 indicates whether the software believes the + laptop is docked in a docking station. + +What: /sys/devices/platform/dock.N/undock +Date: Dec, 2006 +KernelVersion: 2.6.19 +Contact: linux-acpi@vger.kernel.org +Description: + (WO) Writing to this file causes the software to initiate an + undock request to the firmware. + +What: /sys/devices/platform/dock.N/uid +Date: Feb, 2007 +KernelVersion: v2.6.21 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Displays the docking station the laptop is docked to. + +What: /sys/devices/platform/dock.N/flags +Date: May, 2007 +KernelVersion: v2.6.21 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Show dock station flags, useful for checking if undock + request has been made by the user (from the immediate_undock + option). + +What: /sys/devices/platform/dock.N/type +Date: Aug, 2008 +KernelVersion: v2.6.27 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Display the dock station type- dock_station, ata_bay or + battery_bay. diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index bfd29bc8d37a..4ed63b6cfb15 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -108,6 +108,8 @@ Description: CPU topology files that describe a logical CPU's relationship What: /sys/devices/system/cpu/cpuidle/current_driver /sys/devices/system/cpu/cpuidle/current_governer_ro + /sys/devices/system/cpu/cpuidle/available_governors + /sys/devices/system/cpu/cpuidle/current_governor Date: September 2007 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> Description: Discover cpuidle policy and mechanism @@ -119,13 +121,84 @@ Description: Discover cpuidle policy and mechanism Idle policy (governor) is differentiated from idle mechanism (driver) - current_driver: displays current idle mechanism + current_driver: (RO) displays current idle mechanism - current_governor_ro: displays current idle policy + current_governor_ro: (RO) displays current idle policy + + With the cpuidle_sysfs_switch boot option enabled (meant for + developer testing), the following three attributes are visible + instead: + + current_driver: same as described above + + available_governors: (RO) displays a space separated list of + available governors + + current_governor: (RW) displays current idle policy. Users can + switch the governor at runtime by writing to this file. See files in Documentation/cpuidle/ for more information. +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/name + /sys/devices/system/cpu/cpuX/cpuidle/stateN/latency + /sys/devices/system/cpu/cpuX/cpuidle/stateN/power + /sys/devices/system/cpu/cpuX/cpuidle/stateN/time + /sys/devices/system/cpu/cpuX/cpuidle/stateN/usage +Date: September 2007 +KernelVersion: v2.6.24 +Contact: Linux power management list <linux-pm@vger.kernel.org> +Description: + The directory /sys/devices/system/cpu/cpuX/cpuidle contains per + logical CPU specific cpuidle information for each online cpu X. + The processor idle states which are available for use have the + following attributes: + + name: (RO) Name of the idle state (string). + + latency: (RO) The latency to exit out of this idle state (in + microseconds). + + power: (RO) The power consumed while in this idle state (in + milliwatts). + + time: (RO) The total time spent in this idle state (in microseconds). + + usage: (RO) Number of times this state was entered (a count). + + +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/desc +Date: February 2008 +KernelVersion: v2.6.25 +Contact: Linux power management list <linux-pm@vger.kernel.org> +Description: + (RO) A small description about the idle state (string). + + +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/disable +Date: March 2012 +KernelVersion: v3.10 +Contact: Linux power management list <linux-pm@vger.kernel.org> +Description: + (RW) Option to disable this idle state (bool). The behavior and + the effect of the disable variable depends on the implementation + of a particular governor. In the ladder governor, for example, + it is not coherent, i.e. if one is disabling a light state, then + all deeper states are disabled as well, but the disable variable + does not reflect it. Likewise, if one enables a deep state but a + lighter state still is disabled, then this has no effect. + + +What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/residency +Date: March 2014 +KernelVersion: v3.15 +Contact: Linux power management list <linux-pm@vger.kernel.org> +Description: + (RO) Display the target residency i.e. the minimum amount of + time (in microseconds) this cpu should spend in this idle state + to make the transition worth the effort. + + What: /sys/devices/system/cpu/cpu#/cpufreq/* Date: pre-git history Contact: linux-pm@vger.kernel.org diff --git a/Documentation/ABI/testing/sysfs-platform-dptf b/Documentation/ABI/testing/sysfs-platform-dptf new file mode 100644 index 000000000000..325dc0667dbb --- /dev/null +++ b/Documentation/ABI/testing/sysfs-platform-dptf @@ -0,0 +1,40 @@ +What: /sys/bus/platform/devices/INT3407:00/dptf_power/charger_type +Date: Jul, 2016 +KernelVersion: v4.10 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) The charger type - Traditional, Hybrid or NVDC. + +What: /sys/bus/platform/devices/INT3407:00/dptf_power/adapter_rating_mw +Date: Jul, 2016 +KernelVersion: v4.10 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Adapter rating in milliwatts (the maximum Adapter power). + Must be 0 if no AC Adaptor is plugged in. + +What: /sys/bus/platform/devices/INT3407:00/dptf_power/max_platform_power_mw +Date: Jul, 2016 +KernelVersion: v4.10 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Maximum platform power that can be supported by the battery + in milliwatts. + +What: /sys/bus/platform/devices/INT3407:00/dptf_power/platform_power_source +Date: Jul, 2016 +KernelVersion: v4.10 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) Display the platform power source + 0x00 = DC + 0x01 = AC + 0x02 = USB + 0x03 = Wireless Charger + +What: /sys/bus/platform/devices/INT3407:00/dptf_power/battery_steady_power +Date: Jul, 2016 +KernelVersion: v4.10 +Contact: linux-acpi@vger.kernel.org +Description: + (RO) The maximum sustained power for battery in milliwatts. diff --git a/Documentation/atomic_bitops.txt b/Documentation/atomic_bitops.txt index 5550bfdcce5f..be70b32c95d9 100644 --- a/Documentation/atomic_bitops.txt +++ b/Documentation/atomic_bitops.txt @@ -58,7 +58,12 @@ Like with atomic_t, the rule of thumb is: - RMW operations that have a return value are fully ordered. -Except for test_and_set_bit_lock() which has ACQUIRE semantics and + - RMW operations that are conditional are unordered on FAILURE, + otherwise the above rules apply. In the case of test_and_{}_bit() operations, + if the bit in memory is unchanged by the operation then it is deemed to have + failed. + +Except for a successful test_and_set_bit_lock() which has ACQUIRE semantics and clear_bit_unlock() which has RELEASE semantics. Since a platform only has a single means of achieving atomic operations diff --git a/Documentation/devicetree/bindings/power/mti,mips-cpc.txt b/Documentation/devicetree/bindings/power/mti,mips-cpc.txt new file mode 100644 index 000000000000..c6b82511ae8a --- /dev/null +++ b/Documentation/devicetree/bindings/power/mti,mips-cpc.txt @@ -0,0 +1,8 @@ +Binding for MIPS Cluster Power Controller (CPC). + +This binding allows a system to specify where the CPC registers are +located. + +Required properties: +compatible : Should be "mti,mips-cpc". +regs: Should describe the address & size of the CPC register region. diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt b/Documentation/features/sched/membarrier-sync-core/arch-support.txt new file mode 100644 index 000000000000..2c815a7f1ba7 --- /dev/null +++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt @@ -0,0 +1,62 @@ +# +# Feature name: membarrier-sync-core +# Kconfig: ARCH_HAS_MEMBARRIER_SYNC_CORE +# description: arch supports core serializing membarrier +# +# Architecture requirements +# +# * arm64 +# +# Rely on eret context synchronization when returning from IPI handler, and +# when returning to user-space. +# +# * x86 +# +# x86-32 uses IRET as return from interrupt, which takes care of the IPI. +# However, it uses both IRET and SYSEXIT to go back to user-space. The IRET +# instruction is core serializing, but not SYSEXIT. +# +# x86-64 uses IRET as return from interrupt, which takes care of the IPI. +# However, it can return to user-space through either SYSRETL (compat code), +# SYSRETQ, or IRET. +# +# Given that neither SYSRET{L,Q}, nor SYSEXIT, are core serializing, we rely +# instead on write_cr3() performed by switch_mm() to provide core serialization +# after changing the current mm, and deal with the special case of kthread -> +# uthread (temporarily keeping current mm into active_mm) by issuing a +# sync_core_before_usermode() in that specific case. +# + ----------------------- + | arch |status| + ----------------------- + | alpha: | TODO | + | arc: | TODO | + | arm: | TODO | + | arm64: | ok | + | blackfin: | TODO | + | c6x: | TODO | + | cris: | TODO | + | frv: | TODO | + | h8300: | TODO | + | hexagon: | TODO | + | ia64: | TODO | + | m32r: | TODO | + | m68k: | TODO | + | metag: | TODO | + | microblaze: | TODO | + | mips: | TODO | + | mn10300: | TODO | + | nios2: | TODO | + | openrisc: | TODO | + | parisc: | TODO | + | powerpc: | TODO | + | s390: | TODO | + | score: | TODO | + | sh: | TODO | + | sparc: | TODO | + | tile: | TODO | + | um: | TODO | + | unicore32: | TODO | + | x86: | ok | + | xtensa: | TODO | + ----------------------- diff --git a/Documentation/locking/mutex-design.txt b/Documentation/locking/mutex-design.txt index 60c482df1a38..818aca19612f 100644 --- a/Documentation/locking/mutex-design.txt +++ b/Documentation/locking/mutex-design.txt @@ -21,37 +21,23 @@ Implementation -------------- Mutexes are represented by 'struct mutex', defined in include/linux/mutex.h -and implemented in kernel/locking/mutex.c. These locks use a three -state atomic counter (->count) to represent the different possible -transitions that can occur during the lifetime of a lock: - - 1: unlocked - 0: locked, no waiters - negative: locked, with potential waiters - -In its most basic form it also includes a wait-queue and a spinlock -that serializes access to it. CONFIG_SMP systems can also include -a pointer to the lock task owner (->owner) as well as a spinner MCS -lock (->osq), both described below in (ii). +and implemented in kernel/locking/mutex.c. These locks use an atomic variable +(->owner) to keep track of the lock state during its lifetime. Field owner +actually contains 'struct task_struct *' to the current lock owner and it is +therefore NULL if not currently owned. Since task_struct pointers are aligned +at at least L1_CACHE_BYTES, low bits (3) are used to store extra state (e.g., +if waiter list is non-empty). In its most basic form it also includes a +wait-queue and a spinlock that serializes access to it. Furthermore, +CONFIG_MUTEX_SPIN_ON_OWNER=y systems use a spinner MCS lock (->osq), described +below in (ii). When acquiring a mutex, there are three possible paths that can be taken, depending on the state of the lock: -(i) fastpath: tries to atomically acquire the lock by decrementing the - counter. If it was already taken by another task it goes to the next - possible path. This logic is architecture specific. On x86-64, the - locking fastpath is 2 instructions: - - 0000000000000e10 <mutex_lock>: - e21: f0 ff 0b lock decl (%rbx) - e24: 79 08 jns e2e <mutex_lock+0x1e> - - the unlocking fastpath is equally tight: - - 0000000000000bc0 <mutex_unlock>: - bc8: f0 ff 07 lock incl (%rdi) - bcb: 7f 0a jg bd7 <mutex_unlock+0x17> - +(i) fastpath: tries to atomically acquire the lock by cmpxchg()ing the owner with + the current task. This only works in the uncontended case (cmpxchg() checks + against 0UL, so all 3 state bits above have to be 0). If the lock is + contended it goes to the next possible path. (ii) midpath: aka optimistic spinning, tries to spin for acquisition while the lock owner is running and there are no other tasks ready @@ -143,11 +129,10 @@ Test if the mutex is taken: Disadvantages ------------- -Unlike its original design and purpose, 'struct mutex' is larger than -most locks in the kernel. E.g: on x86-64 it is 40 bytes, almost twice -as large as 'struct semaphore' (24 bytes) and tied, along with rwsems, -for the largest lock in the kernel. Larger structure sizes mean more -CPU cache and memory footprint. +Unlike its original design and purpose, 'struct mutex' is among the largest +locks in the kernel. E.g: on x86-64 it is 32 bytes, where 'struct semaphore' +is 24 bytes and rw_semaphore is 40 bytes. Larger structure sizes mean more CPU +cache and memory footprint. When to use mutexes ------------------- diff --git a/Documentation/networking/segmentation-offloads.txt b/Documentation/networking/segmentation-offloads.txt index 2f09455a993a..d47480b61ac6 100644 --- a/Documentation/networking/segmentation-offloads.txt +++ b/Documentation/networking/segmentation-offloads.txt @@ -13,6 +13,7 @@ The following technologies are described: * Generic Segmentation Offload - GSO * Generic Receive Offload - GRO * Partial Generic Segmentation Offload - GSO_PARTIAL + * SCTP accelleration with GSO - GSO_BY_FRAGS TCP Segmentation Offload ======================== @@ -49,6 +50,10 @@ datagram into multiple IPv4 fragments. Many of the requirements for UDP fragmentation offload are the same as TSO. However the IPv4 ID for fragments should not increment as a single IPv4 datagram is fragmented. +UFO is deprecated: modern kernels will no longer generate UFO skbs, but can +still receive them from tuntap and similar devices. Offload of UDP-based +tunnel protocols is still supported. + IPIP, SIT, GRE, UDP Tunnel, and Remote Checksum Offloads ======================================================== @@ -83,10 +88,10 @@ SKB_GSO_UDP_TUNNEL_CSUM. These two additional tunnel types reflect the fact that the outer header also requests to have a non-zero checksum included in the outer header. -Finally there is SKB_GSO_REMCSUM which indicates that a given tunnel header -has requested a remote checksum offload. In this case the inner headers -will be left with a partial checksum and only the outer header checksum -will be computed. +Finally there is SKB_GSO_TUNNEL_REMCSUM which indicates that a given tunnel +header has requested a remote checksum offload. In this case the inner +headers will be left with a partial checksum and only the outer header +checksum will be computed. Generic Segmentation Offload ============================ @@ -128,3 +133,28 @@ values for if the header was simply duplicated. The one exception to this is the outer IPv4 ID field. It is up to the device drivers to guarantee that the IPv4 ID field is incremented in the case that a given header does not have the DF bit set. + +SCTP accelleration with GSO +=========================== + +SCTP - despite the lack of hardware support - can still take advantage of +GSO to pass one large packet through the network stack, rather than +multiple small packets. + +This requires a different approach to other offloads, as SCTP packets +cannot be just segmented to (P)MTU. Rather, the chunks must be contained in +IP segments, padding respected. So unlike regular GSO, SCTP can't just +generate a big skb, set gso_size to the fragmentation point and deliver it +to IP layer. + +Instead, the SCTP protocol layer builds an skb with the segments correctly +padded and stored as chained skbs, and skb_segment() splits based on those. +To signal this, gso_size is set to the special value GSO_BY_FRAGS. + +Therefore, any code in the core networking stack must be aware of the +possibility that gso_size will be GSO_BY_FRAGS and handle that case +appropriately. (For size checks, the skb_gso_validate_*_len family of +helpers do this automatically.) + +This also affects drivers with the NETIF_F_FRAGLIST & NETIF_F_GSO_SCTP bits +set. Note also that NETIF_F_GSO_SCTP is included in NETIF_F_GSO_SOFTWARE. |