From f58ee00f1547ceb17b610ecfce2aa9097f1f9737 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sun, 4 Oct 2009 02:28:42 +0200 Subject: HWPOISON: Add brief hwpoison description to Documentation Signed-off-by: Andi Kleen --- Documentation/vm/hwpoison.txt | 136 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 Documentation/vm/hwpoison.txt (limited to 'Documentation') diff --git a/Documentation/vm/hwpoison.txt b/Documentation/vm/hwpoison.txt new file mode 100644 index 000000000000..3ffadf8da61f --- /dev/null +++ b/Documentation/vm/hwpoison.txt @@ -0,0 +1,136 @@ +What is hwpoison? + +Upcoming Intel CPUs have support for recovering from some memory errors +(``MCA recovery''). This requires the OS to declare a page "poisoned", +kill the processes associated with it and avoid using it in the future. + +This patchkit implements the necessary infrastructure in the VM. + +To quote the overview comment: + + * High level machine check handler. Handles pages reported by the + * hardware as being corrupted usually due to a 2bit ECC memory or cache + * failure. + * + * This focusses on pages detected as corrupted in the background. + * When the current CPU tries to consume corruption the currently + * running process can just be killed directly instead. This implies + * that if the error cannot be handled for some reason it's safe to + * just ignore it because no corruption has been consumed yet. Instead + * when that happens another machine check will happen. + * + * Handles page cache pages in various states. The tricky part + * here is that we can access any page asynchronous to other VM + * users, because memory failures could happen anytime and anywhere, + * possibly violating some of their assumptions. This is why this code + * has to be extremely careful. Generally it tries to use normal locking + * rules, as in get the standard locks, even if that means the + * error handling takes potentially a long time. + * + * Some of the operations here are somewhat inefficient and have non + * linear algorithmic complexity, because the data structures have not + * been optimized for this case. This is in particular the case + * for the mapping from a vma to a process. Since this case is expected + * to be rare we hope we can get away with this. + +The code consists of a the high level handler in mm/memory-failure.c, +a new page poison bit and various checks in the VM to handle poisoned +pages. + +The main target right now is KVM guests, but it works for all kinds +of applications. KVM support requires a recent qemu-kvm release. + +For the KVM use there was need for a new signal type so that +KVM can inject the machine check into the guest with the proper +address. This in theory allows other applications to handle +memory failures too. The expection is that near all applications +won't do that, but some very specialized ones might. + +--- + +There are two (actually three) modi memory failure recovery can be in: + +vm.memory_failure_recovery sysctl set to zero: + All memory failures cause a panic. Do not attempt recovery. + (on x86 this can be also affected by the tolerant level of the + MCE subsystem) + +early kill + (can be controlled globally and per process) + Send SIGBUS to the application as soon as the error is detected + This allows applications who can process memory errors in a gentle + way (e.g. drop affected object) + This is the mode used by KVM qemu. + +late kill + Send SIGBUS when the application runs into the corrupted page. + This is best for memory error unaware applications and default + Note some pages are always handled as late kill. + +--- + +User control: + +vm.memory_failure_recovery + See sysctl.txt + +vm.memory_failure_early_kill + Enable early kill mode globally + +PR_MCE_KILL + Set early/late kill mode/revert to system default + arg1: PR_MCE_KILL_CLEAR: Revert to system default + arg1: PR_MCE_KILL_SET: arg2 defines thread specific mode + PR_MCE_KILL_EARLY: Early kill + PR_MCE_KILL_LATE: Late kill + PR_MCE_KILL_DEFAULT: Use system global default +PR_MCE_KILL_GET + return current mode + + +--- + +Testing: + +madvise(MADV_POISON, ....) + (as root) + Poison a page in the process for testing + + +hwpoison-inject module through debugfs + /sys/debug/hwpoison/corrupt-pfn + +Inject hwpoison fault at PFN echoed into this file + + +Architecture specific MCE injector + +x86 has mce-inject, mce-test + +Some portable hwpoison test programs in mce-test, see blow. + +--- + +References: + +http://halobates.de/mce-lc09-2.pdf + Overview presentation from LinuxCon 09 + +git://git.kernel.org/pub/scm/utils/cpu/mce/mce-test.git + Test suite (hwpoison specific portable tests in tsrc) + +git://git.kernel.org/pub/scm/utils/cpu/mce/mce-inject.git + x86 specific injector + + +--- + +Limitations: + +- Not all page types are supported and never will. Most kernel internal +objects cannot be recovered, only LRU pages for now. +- Right now hugepage support is missing. + +--- +Andi Kleen, Oct 2009 + -- cgit v1.2.3 From 99b830aa553668a2c433e4cbff130224a75c74bb Mon Sep 17 00:00:00 2001 From: David Vrabel Date: Mon, 12 Oct 2009 15:45:13 +0000 Subject: USB: rename Documentation/ABI/.../sysfs-class-usb_host The usb_host class is no more. Rename its documentation file (which only contained WUSB specific files) to .../sysfs-class-uwb_rc-wusbhc. Signed-off-by: David Vrabel Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-class-usb_host | 25 ---------------------- .../ABI/testing/sysfs-class-uwb_rc-wusbhc | 25 ++++++++++++++++++++++ 2 files changed, 25 insertions(+), 25 deletions(-) delete mode 100644 Documentation/ABI/testing/sysfs-class-usb_host create mode 100644 Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-class-usb_host b/Documentation/ABI/testing/sysfs-class-usb_host deleted file mode 100644 index 46b66ad1f1b4..000000000000 --- a/Documentation/ABI/testing/sysfs-class-usb_host +++ /dev/null @@ -1,25 +0,0 @@ -What: /sys/class/usb_host/usb_hostN/wusb_chid -Date: July 2008 -KernelVersion: 2.6.27 -Contact: David Vrabel -Description: - Write the CHID (16 space-separated hex octets) for this host controller. - This starts the host controller, allowing it to accept connection from - WUSB devices. - - Set an all zero CHID to stop the host controller. - -What: /sys/class/usb_host/usb_hostN/wusb_trust_timeout -Date: July 2008 -KernelVersion: 2.6.27 -Contact: David Vrabel -Description: - Devices that haven't sent a WUSB packet to the host - within 'wusb_trust_timeout' ms are considered to have - disconnected and are removed. The default value of - 4000 ms is the value required by the WUSB - specification. - - Since this relates to security (specifically, the - lifetime of PTKs and GTKs) it should not be changed - from the default. diff --git a/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc new file mode 100644 index 000000000000..4e8106f7cfd9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-uwb_rc-wusbhc @@ -0,0 +1,25 @@ +What: /sys/class/uwb_rc/uwbN/wusbhc/wusb_chid +Date: July 2008 +KernelVersion: 2.6.27 +Contact: David Vrabel +Description: + Write the CHID (16 space-separated hex octets) for this host controller. + This starts the host controller, allowing it to accept connection from + WUSB devices. + + Set an all zero CHID to stop the host controller. + +What: /sys/class/uwb_rc/uwbN/wusbhc/wusb_trust_timeout +Date: July 2008 +KernelVersion: 2.6.27 +Contact: David Vrabel +Description: + Devices that haven't sent a WUSB packet to the host + within 'wusb_trust_timeout' ms are considered to have + disconnected and are removed. The default value of + 4000 ms is the value required by the WUSB + specification. + + Since this relates to security (specifically, the + lifetime of PTKs and GTKs) it should not be changed + from the default. -- cgit v1.2.3 From 1243ba98e3abecd12e9e90dd390801b95ef070f2 Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Wed, 14 Oct 2009 12:43:22 -0600 Subject: Update flex_arrays.txt The 2.6.32 merge window brought a number of changes to the flexible array API; this patch updates the documentation to match the new state of affairs. Acked-by: David Rientjes Signed-off-by: Jonathan Corbet --- Documentation/flexible-arrays.txt | 43 +++++++++++++++++++++++++++++---------- 1 file changed, 32 insertions(+), 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/flexible-arrays.txt b/Documentation/flexible-arrays.txt index 84eb26808dee..cb8a3a00cc92 100644 --- a/Documentation/flexible-arrays.txt +++ b/Documentation/flexible-arrays.txt @@ -1,5 +1,5 @@ Using flexible arrays in the kernel -Last updated for 2.6.31 +Last updated for 2.6.32 Jonathan Corbet Large contiguous memory allocations can be unreliable in the Linux kernel. @@ -40,6 +40,13 @@ argument is passed directly to the internal memory allocation calls. With the current code, using flags to ask for high memory is likely to lead to notably unpleasant side effects. +It is also possible to define flexible arrays at compile time with: + + DEFINE_FLEX_ARRAY(name, element_size, total); + +This macro will result in a definition of an array with the given name; the +element size and total will be checked for validity at compile time. + Storing data into a flexible array is accomplished with a call to: int flex_array_put(struct flex_array *array, unsigned int element_nr, @@ -76,16 +83,30 @@ particular element has never been allocated. Note that it is possible to get back a valid pointer for an element which has never been stored in the array. Memory for array elements is allocated one page at a time; a single allocation could provide memory for several -adjacent elements. The flexible array code does not know if a specific -element has been written; it only knows if the associated memory is -present. So a flex_array_get() call on an element which was never stored -in the array has the potential to return a pointer to random data. If the -caller does not have a separate way to know which elements were actually -stored, it might be wise, at least, to add GFP_ZERO to the flags argument -to ensure that all elements are zeroed. - -There is no way to remove a single element from the array. It is possible, -though, to remove all elements with a call to: +adjacent elements. Flexible array elements are normally initialized to the +value FLEX_ARRAY_FREE (defined as 0x6c in ), so errors +involving that number probably result from use of unstored array entries. +Note that, if array elements are allocated with __GFP_ZERO, they will be +initialized to zero and this poisoning will not happen. + +Individual elements in the array can be cleared with: + + int flex_array_clear(struct flex_array *array, unsigned int element_nr); + +This function will set the given element to FLEX_ARRAY_FREE and return +zero. If storage for the indicated element is not allocated for the array, +flex_array_clear() will return -EINVAL instead. Note that clearing an +element does not release the storage associated with it; to reduce the +allocated size of an array, call: + + int flex_array_shrink(struct flex_array *array); + +The return value will be the number of pages of memory actually freed. +This function works by scanning the array for pages containing nothing but +FLEX_ARRAY_FREE bytes, so (1) it can be expensive, and (2) it will not work +if the array's pages are allocated with __GFP_ZERO. + +It is possible to remove all elements of an array with a call to: void flex_array_free_parts(struct flex_array *array); -- cgit v1.2.3 From cdc321ff0af78e818c97d4787f62bf52bdf9db2a Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Mon, 29 Jun 2009 11:13:30 -0400 Subject: inotify: deprecate the inotify kernel interface In 2.6.33 there will be no users of the inotify interface. Mark it for removal as fsnotify is more generic and is easier to use. Signed-off-by: Eric Paris --- Documentation/feature-removal-schedule.txt | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'Documentation') diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 04e6c819b28a..bc693fffabe0 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -418,6 +418,14 @@ When: 2.6.33 Why: Should be implemented in userspace, policy daemon. Who: Johannes Berg +--------------------------- + +What: CONFIG_INOTIFY +When: 2.6.33 +Why: last user (audit) will be converted to the newer more generic + and more easily maintained fsnotify subsystem +Who: Eric Paris + ---------------------------- What: lock_policy_rwsem_* and unlock_policy_rwsem_* will not be -- cgit v1.2.3 From e95646c3ec33c8ec0693992da4332a6b32eb7e31 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Wed, 30 Sep 2009 11:17:21 +0200 Subject: virtio: let header files include virtio_ids.h Rusty, commit 3ca4f5ca73057a617f9444a91022d7127041970a virtio: add virtio IDs file moved all device IDs into a single file. While the change itself is a very good one, it can break userspace applications. For example if a userspace tool wanted to get the ID of virtio_net it used to include virtio_net.h. This does no longer work, since virtio_net.h does not include virtio_ids.h. This patch moves all "#include " from the C files into the header files, making the header files compatible with the old ones. In addition, this patch exports virtio_ids.h to userspace. CC: Fernando Luis Vazquez Cao Signed-off-by: Christian Borntraeger Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 1 - 1 file changed, 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index ba9373f82ab5..098de5bce00a 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -42,7 +42,6 @@ #include #include "linux/lguest_launcher.h" #include "linux/virtio_config.h" -#include #include "linux/virtio_net.h" #include "linux/virtio_blk.h" #include "linux/virtio_console.h" -- cgit v1.2.3 From 67b394f7f26d84edb7294cc6528ab7ca6daa2ad1 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Fri, 23 Oct 2009 19:36:18 -0400 Subject: tracing: Fix comment typo and documentation example Trivial patch to fix a documentation example and to fix a comment. Signed-off-by: Jiri Olsa Signed-off-by: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <20091023233646.871719877@goodmis.org> Signed-off-by: Ingo Molnar --- Documentation/trace/ftrace.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt index 957b22fde2df..8179692fbb90 100644 --- a/Documentation/trace/ftrace.txt +++ b/Documentation/trace/ftrace.txt @@ -1231,6 +1231,7 @@ something like this simple program: #include #include #include +#include #define _STR(x) #x #define STR(x) _STR(x) @@ -1265,6 +1266,7 @@ const char *find_debugfs(void) return NULL; } + strcat(debugfs, "/tracing/"); debugfs_found = 1; return debugfs; -- cgit v1.2.3 From 115a57c5b31ab560574fe1a09deaba2ae89e77b5 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Mon, 26 Oct 2009 16:50:07 -0700 Subject: hwmon: enhance the sysfs API for power meters Augment the documentation of the hwmon sysfs API to accomodate ACPI power meters and the current desired behavior of power capping hardware drivers. Signed-off-by: Darrick J. Wong Cc: Zhang Rui Cc: Pavel Machek Cc: Len Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/hwmon/sysfs-interface | 57 ++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/hwmon/sysfs-interface b/Documentation/hwmon/sysfs-interface index dcbd502c8792..82def883361b 100644 --- a/Documentation/hwmon/sysfs-interface +++ b/Documentation/hwmon/sysfs-interface @@ -353,10 +353,20 @@ power[1-*]_average Average power use Unit: microWatt RO -power[1-*]_average_interval Power use averaging interval +power[1-*]_average_interval Power use averaging interval. A poll + notification is sent to this file if the + hardware changes the averaging interval. Unit: milliseconds RW +power[1-*]_average_interval_max Maximum power use averaging interval + Unit: milliseconds + RO + +power[1-*]_average_interval_min Minimum power use averaging interval + Unit: milliseconds + RO + power[1-*]_average_highest Historical average maximum power use Unit: microWatt RO @@ -365,6 +375,18 @@ power[1-*]_average_lowest Historical average minimum power use Unit: microWatt RO +power[1-*]_average_max A poll notification is sent to + power[1-*]_average when power use + rises above this value. + Unit: microWatt + RW + +power[1-*]_average_min A poll notification is sent to + power[1-*]_average when power use + sinks below this value. + Unit: microWatt + RW + power[1-*]_input Instantaneous power use Unit: microWatt RO @@ -381,6 +403,39 @@ power[1-*]_reset_history Reset input_highest, input_lowest, average_highest and average_lowest. WO +power[1-*]_accuracy Accuracy of the power meter. + Unit: Percent + RO + +power[1-*]_alarm 1 if the system is drawing more power than the + cap allows; 0 otherwise. A poll notification is + sent to this file when the power use exceeds the + cap. This file only appears if the cap is known + to be enforced by hardware. + RO + +power[1-*]_cap If power use rises above this limit, the + system should take action to reduce power use. + A poll notification is sent to this file if the + cap is changed by the hardware. The *_cap + files only appear if the cap is known to be + enforced by hardware. + Unit: microWatt + RW + +power[1-*]_cap_hyst Margin of hysteresis built around capping and + notification. + Unit: microWatt + RW + +power[1-*]_cap_max Maximum cap that can be set. + Unit: microWatt + RO + +power[1-*]_cap_min Minimum cap that can be set. + Unit: microWatt + RO + ********** * Energy * ********** -- cgit v1.2.3 From 468727ab1273a0f95562befa611a3ce39778599c Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:15 -0600 Subject: Documentation: ABI: rename sysfs-devices-cache_disable properly Rename sysfs-devices-cache_disable to sysfs-devices-system-cpu, in order to keep a stricter correlation between a sysfs directory and its documentation. Reported-by: David Rientjes Signed-off-by: Alex Chiang Acked-by: David Rientjes Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-cache_disable | 18 ------------------ Documentation/ABI/testing/sysfs-devices-system-cpu | 18 ++++++++++++++++++ 2 files changed, 18 insertions(+), 18 deletions(-) delete mode 100644 Documentation/ABI/testing/sysfs-devices-cache_disable create mode 100644 Documentation/ABI/testing/sysfs-devices-system-cpu (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-cache_disable b/Documentation/ABI/testing/sysfs-devices-cache_disable deleted file mode 100644 index 175bb4f70512..000000000000 --- a/Documentation/ABI/testing/sysfs-devices-cache_disable +++ /dev/null @@ -1,18 +0,0 @@ -What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X -Date: August 2008 -KernelVersion: 2.6.27 -Contact: mark.langsdorf@amd.com -Description: These files exist in every cpu's cache index directories. - There are currently 2 cache_disable_# files in each - directory. Reading from these files on a supported - processor will return that cache disable index value - for that processor and node. Writing to one of these - files will cause the specificed cache index to be disabled. - - Currently, only AMD Family 10h Processors support cache index - disable, and only for their L3 caches. See the BIOS and - Kernel Developer's Guide at - http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf - for formatting information and other details on the - cache index disable. -Users: joachim.deguara@amd.com diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu new file mode 100644 index 000000000000..175bb4f70512 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -0,0 +1,18 @@ +What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X +Date: August 2008 +KernelVersion: 2.6.27 +Contact: mark.langsdorf@amd.com +Description: These files exist in every cpu's cache index directories. + There are currently 2 cache_disable_# files in each + directory. Reading from these files on a supported + processor will return that cache disable index value + for that processor and node. Writing to one of these + files will cause the specificed cache index to be disabled. + + Currently, only AMD Family 10h Processors support cache index + disable, and only for their L3 caches. See the BIOS and + Kernel Developer's Guide at + http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf + for formatting information and other details on the + cache index disable. +Users: joachim.deguara@amd.com -- cgit v1.2.3 From 2ceb3fb0a78c671892b01319ac8e3baede33a78c Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:20 -0600 Subject: Documentation: ABI: document /sys/devices/system/cpu/ This interface has been around for a long time, but hasn't been officially documented. Document the top level sysfs directory for CPU attributes. Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 175bb4f70512..86126b187ae6 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -1,3 +1,15 @@ +What: /sys/devices/system/cpu/ +Date: pre-git history +Contact: Linux kernel mailing list +Description: + A collection of both global and individual CPU attributes + + Individual CPU attributes are contained in subdirectories + named by the kernel's logical CPU number, e.g.: + + /sys/devices/system/cpu/cpu#/ + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 -- cgit v1.2.3 From d93fc863d2d2cea1057996c39cef368f41741448 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:25 -0600 Subject: Documentation: ABI: /sys/devices/system/cpu/ topology files Add brief descriptions for the following sysfs files: /sys/devices/system/cpu/kernel_max /sys/devices/system/cpu/offline /sys/devices/system/cpu/online /sys/devices/system/cpu/possible /sys/devices/system/cpu/present Excerpted the relevant information from Documentation/cputopology.txt and pointed back to cputopology.txt as the authoritative source of information. Cc: Mike Travis Cc: Rusty Russell Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 28 ++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 86126b187ae6..871acdbeed1a 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -10,6 +10,34 @@ Description: /sys/devices/system/cpu/cpu#/ +What: /sys/devices/system/cpu/kernel_max + /sys/devices/system/cpu/offline + /sys/devices/system/cpu/online + /sys/devices/system/cpu/possible + /sys/devices/system/cpu/present +Date: December 2008 +Contact: Linux kernel mailing list +Description: CPU topology files that describe kernel limits related to + hotplug. Briefly: + + kernel_max: the maximum cpu index allowed by the kernel + configuration. + + offline: cpus that are not online because they have been + HOTPLUGGED off or exceed the limit of cpus allowed by the + kernel configuration (kernel_max above). + + online: cpus that are online and being scheduled. + + possible: cpus that have been allocated resources and can be + brought online if they are present. + + present: cpus that have been identified as being present in + the system. + + See Documentation/cputopology.txt for more information. + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 -- cgit v1.2.3 From 663fb2fc733006f685400fb44551303b72b61a88 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:31 -0600 Subject: Documentation: ABI: /sys/devices/system/cpu/cpu#/ topology files Add brief descriptions for the following sysfs files: /sys/devices/system/cpu/cpu#/topology/core_id /sys/devices/system/cpu/cpu#/topology/core_siblings /sys/devices/system/cpu/cpu#/topology/core_siblings_list /sys/devices/system/cpu/cpu#/topology/physical_package_id /sys/devices/system/cpu/cpu#/topology/thread_siblings /sys/devices/system/cpu/cpu#/topology/thread_siblings_list The descriptions in Documentation/cputopology.txt weren't very informative, so I attempted a better description based on code reading and hopeful guessing. Updated Documentation/cputopology.txt with the better descriptions and fixed some style issues. Cc: Mike Travis Cc: Rusty Russell Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 39 ++++++++++++++++++ Documentation/cputopology.txt | 47 ++++++++++++++-------- 2 files changed, 69 insertions(+), 17 deletions(-) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 871acdbeed1a..2ade5c0809a0 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -38,6 +38,45 @@ Description: CPU topology files that describe kernel limits related to See Documentation/cputopology.txt for more information. +What: /sys/devices/system/cpu/cpu#/topology/core_id + /sys/devices/system/cpu/cpu#/topology/core_siblings + /sys/devices/system/cpu/cpu#/topology/core_siblings_list + /sys/devices/system/cpu/cpu#/topology/physical_package_id + /sys/devices/system/cpu/cpu#/topology/thread_siblings + /sys/devices/system/cpu/cpu#/topology/thread_siblings_list +Date: December 2008 +Contact: Linux kernel mailing list +Description: CPU topology files that describe a logical CPU's relationship + to other cores and threads in the same physical package. + + One cpu# directory is created per logical CPU in the system, + e.g. /sys/devices/system/cpu/cpu42/. + + Briefly, the files above are: + + core_id: the CPU core ID of cpu#. Typically it is the + hardware platform's identifier (rather than the kernel's). + The actual value is architecture and platform dependent. + + core_siblings: internal kernel map of cpu#'s hardware threads + within the same physical_package_id. + + core_siblings_list: human-readable list of the logical CPU + numbers within the same physical_package_id as cpu#. + + physical_package_id: physical package id of cpu#. Typically + corresponds to a physical socket number, but the actual value + is architecture and platform dependent. + + thread_siblings: internel kernel map of cpu#'s hardware + threads within the same core as cpu# + + thread_siblings_list: human-readable list of cpu#'s hardware + threads within the same core as cpu# + + See Documentation/cputopology.txt for more information. + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index b41f3e58aefa..f1c5c4bccd3e 100644 --- a/Documentation/cputopology.txt +++ b/Documentation/cputopology.txt @@ -1,15 +1,28 @@ -Export cpu topology info via sysfs. Items (attributes) are similar +Export CPU topology info via sysfs. Items (attributes) are similar to /proc/cpuinfo. 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id: -represent the physical package id of cpu X; + + physical package id of cpuX. Typically corresponds to a physical + socket number, but the actual value is architecture and platform + dependent. + 2) /sys/devices/system/cpu/cpuX/topology/core_id: -represent the cpu core id to cpu X; + + the CPU core ID of cpuX. Typically it is the hardware platform's + identifier (rather than the kernel's). The actual value is + architecture and platform dependent. + 3) /sys/devices/system/cpu/cpuX/topology/thread_siblings: -represent the thread siblings to cpu X in the same core; + + internel kernel map of cpuX's hardware threads within the same + core as cpuX + 4) /sys/devices/system/cpu/cpuX/topology/core_siblings: -represent the thread siblings to cpu X in the same physical package; + + internal kernel map of cpuX's hardware threads within the same + physical_package_id. To implement it in an architecture-neutral way, a new source file, drivers/base/topology.c, is to export the 4 attributes. @@ -32,32 +45,32 @@ not defined by include/asm-XXX/topology.h: 3) thread_siblings: just the given CPU 4) core_siblings: just the given CPU -Additionally, cpu topology information is provided under +Additionally, CPU topology information is provided under /sys/devices/system/cpu and includes these files. The internal source for the output is in brackets ("[]"). - kernel_max: the maximum cpu index allowed by the kernel configuration. + kernel_max: the maximum CPU index allowed by the kernel configuration. [NR_CPUS-1] - offline: cpus that are not online because they have been + offline: CPUs that are not online because they have been HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit - of cpus allowed by the kernel configuration (kernel_max + of CPUs allowed by the kernel configuration (kernel_max above). [~cpu_online_mask + cpus >= NR_CPUS] - online: cpus that are online and being scheduled [cpu_online_mask] + online: CPUs that are online and being scheduled [cpu_online_mask] - possible: cpus that have been allocated resources and can be + possible: CPUs that have been allocated resources and can be brought online if they are present. [cpu_possible_mask] - present: cpus that have been identified as being present in the + present: CPUs that have been identified as being present in the system. [cpu_present_mask] The format for the above output is compatible with cpulist_parse() [see ]. Some examples follow. -In this example, there are 64 cpus in the system but cpus 32-63 exceed +In this example, there are 64 CPUs in the system but cpus 32-63 exceed the kernel max which is limited to 0..31 by the NR_CPUS config option -being 32. Note also that cpus 2 and 4-31 are not online but could be +being 32. Note also that CPUs 2 and 4-31 are not online but could be brought online as they are both present and possible. kernel_max: 31 @@ -67,8 +80,8 @@ brought online as they are both present and possible. present: 0-31 In this example, the NR_CPUS config option is 128, but the kernel was -started with possible_cpus=144. There are 4 cpus in the system and cpu2 -was manually taken offline (and is the only cpu that can be brought +started with possible_cpus=144. There are 4 CPUs in the system and cpu2 +was manually taken offline (and is the only CPU that can be brought online.) kernel_max: 127 @@ -78,4 +91,4 @@ online.) present: 0-3 See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter -as well as more information on the various cpumask's. +as well as more information on the various cpumasks. -- cgit v1.2.3 From e6dcfa7c61c4d31797a12d738bfe0bdec0ca2be1 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:36 -0600 Subject: Documentation: ABI: /sys/devices/system/cpu/sched_[mc|smt]_power_savings Document sched_[mc|smt]_power_savings by reading existing code and git logs. Cc: Suresh Siddha Cc: Ingo Molnar Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 24 ++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 2ade5c0809a0..8cdda1c56980 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -9,6 +9,30 @@ Description: /sys/devices/system/cpu/cpu#/ +What: /sys/devices/system/cpu/sched_mc_power_savings + /sys/devices/system/cpu/sched_smt_power_savings +Date: June 2006 +Contact: Linux kernel mailing list +Description: Discover and adjust the kernel's multi-core scheduler support. + + Possible values are: + + 0 - No power saving load balance (default value) + 1 - Fill one thread/core/package first for long running threads + 2 - Also bias task wakeups to semi-idle cpu package for power + savings + + sched_mc_power_savings is dependent upon SCHED_MC, which is + itself architecture dependent. + + sched_smt_power_savings is dependent upon SCHED_SMT, which + is itself architecture dependent. + + The two files are independent of each other. It is possible + that one file may be present without the other. + + Introduced by git commit 5c45bf27. + What: /sys/devices/system/cpu/kernel_max /sys/devices/system/cpu/offline -- cgit v1.2.3 From c1fb5c475126b77b47ba762f5b48535cd0420d24 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 21:45:41 -0600 Subject: Documentation: ABI: /sys/devices/system/cpu/cpuidle/ Document cpuidle sysfs attributes by reading code, Documentation/cpuidle/, and git logs. Cc: Venki Pallipadi Cc: Len Brown Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 8cdda1c56980..968d8bad3835 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -101,6 +101,26 @@ Description: CPU topology files that describe a logical CPU's relationship See Documentation/cputopology.txt for more information. +What: /sys/devices/system/cpu/cpuidle/current_driver + /sys/devices/system/cpu/cpuidle/current_governer_ro +Date: September 2007 +Contact: Linux kernel mailing list +Description: Discover cpuidle policy and mechanism + + Various CPUs today support multiple idle levels that are + differentiated by varying exit latencies and power + consumption during idle. + + Idle policy (governor) is differentiated from idle mechanism + (driver) + + current_driver: displays current idle mechanism + + current_governor_ro: displays current idle policy + + See files in Documentation/cpuidle/ for more information. + + What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X Date: August 2008 KernelVersion: 2.6.27 -- cgit v1.2.3 From 657348a056eea4a27be20cf8e22c98a252597447 Mon Sep 17 00:00:00 2001 From: Alex Chiang Date: Wed, 21 Oct 2009 22:15:30 -0600 Subject: Documentation: ABI: /sys/devices/system/cpu/cpu#/node Describe NUMA node symlink created for CPUs when CONFIG_NUMA is set. Cc: Randy Dunlap Signed-off-by: Alex Chiang Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-devices-system-cpu | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 968d8bad3835..a703b9e9aeb9 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -62,6 +62,21 @@ Description: CPU topology files that describe kernel limits related to See Documentation/cputopology.txt for more information. + +What: /sys/devices/system/cpu/cpu#/node +Date: October 2009 +Contact: Linux memory management mailing list +Description: Discover NUMA node a CPU belongs to + + When CONFIG_NUMA is enabled, a symbolic link that points + to the corresponding NUMA node directory. + + For example, the following symlink is created for cpu42 + in NUMA node 2: + + /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2 + + What: /sys/devices/system/cpu/cpu#/topology/core_id /sys/devices/system/cpu/cpu#/topology/core_siblings /sys/devices/system/cpu/cpu#/topology/core_siblings_list -- cgit v1.2.3 From 23aebca486429b74c35b41ac5cac7ce97609fd6a Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Mon, 2 Nov 2009 14:10:59 +0100 Subject: ALSA: dummy - Fix descriptions of pcm_substreams parameter Now up to 128 substreams are supported. Reported-by: Adrian Bridgett Signed-off-by: Takashi Iwai --- Documentation/sound/alsa/ALSA-Configuration.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index 1c8eb4518ce0..fd9a2f67edf2 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -522,7 +522,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. pcm_devs - Number of PCM devices assigned to each card (default = 1, up to 4) pcm_substreams - Number of PCM substreams assigned to each PCM - (default = 8, up to 16) + (default = 8, up to 128) hrtimer - Use hrtimer (=1, default) or system timer (=0) fake_buffer - Fake buffer allocations (default = 1) -- cgit v1.2.3 From d4da6c9ccf648f3f1cb5bf9d981a62c253d30e28 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 2 Nov 2009 10:15:27 -0800 Subject: Revert "ext4: Remove journal_checksum mount option and enable it by default" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit d0646f7b636d067d715fab52a2ba9c6f0f46b0d7, as requested by Eric Sandeen. It can basically cause an ext4 filesystem to miss recovery (and thus get mounted with errors) if the journal checksum does not match. Quoth Eric: "My hand-wavy hunch about what is happening is that we're finding a bad checksum on the last partially-written transaction, which is not surprising, but if we have a wrapped log and we're doing the initial scan for head/tail, and we abort scanning on that bad checksum, then we are essentially running an unrecovered filesystem. But that's hand-wavy and I need to go look at the code. We lived without journal checksums on by default until now, and at this point they're doing more harm than good, so we should revert the default-changing commit until we can fix it and do some good power-fail testing with the fixes in place." See http://bugzilla.kernel.org/show_bug.cgi?id=14354 for all the gory details. Requested-by: Eric Sandeen Cc: Theodore Tso Cc: Alexey Fisher Cc: Maxim Levitsky Cc: Aneesh Kumar K.V Cc: Mathias Burén Signed-off-by: Linus Torvalds --- Documentation/filesystems/ext4.txt | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index bf4f4b7e11b3..6d94e0696f8c 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -134,9 +134,15 @@ ro Mount filesystem read only. Note that ext4 will mount options "ro,noload" can be used to prevent writes to the filesystem. +journal_checksum Enable checksumming of the journal transactions. + This will allow the recovery code in e2fsck and the + kernel to detect corruption in the kernel. It is a + compatible change and will be ignored by older kernels. + journal_async_commit Commit block can be written to disk without waiting for descriptor blocks. If enabled older kernels cannot - mount the device. + mount the device. This will enable 'journal_checksum' + internally. journal=update Update the ext4 file system's journal to the current format. -- cgit v1.2.3