mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
synced 2024-12-29 17:22:07 +00:00
A handful of late-arriving documentation fixes.
-----BEGIN PGP SIGNATURE----- iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAl+TK60PHGNvcmJldEBs d24ubmV0AAoJEBdDWhNsDH5YrTMIAJSEchjBnlWOzvW/YmdhWz8+O3+CDPNIiJ2J 01tybiOBj64n0zMP7K6bN8IEjyRIed6L3vBsJxyIOGajkjekJZSqpBT9THy+AJnW ie72nA7DNYucdik8CWCKjyzylunVGfD/ju5uI4o4yBMTvliDlz9ZWIepF1fprfCb rTTyj5o+lsP11EjSSPw7RQIAHYCzFhBRanHqijGQnuEmnNKo+HxULcMwIsAtPjL8 wAgZyi6sr2kllk5ZsGaU8eSwiM4SCcuvOo9W36Eg0bKQnutUClGbAVL0UKy9yFd+ jJXTNDHGs/tBewSVyAmNa90WUORvRASdugI0hz1DdPt4qFIDdTQ= =+uur -----END PGP SIGNATURE----- Merge tag 'docs-5.10-2' of git://git.lwn.net/linux Pull documentation fixes from Jonathan Corbet: "A handful of late-arriving documentation fixes" * tag 'docs-5.10-2' of git://git.lwn.net/linux: docs: Add two missing entries in vm sysctl index docs/vm: trivial fixes to several spelling mistakes docs: submitting-patches: describe preserving review/test tags Documentation: Chinese translation of Documentation/arm64/hugetlbpage.rst Documentation: x86: fix a missing word in x86_64/mm.rst. docs: driver-api: remove a duplicated index entry docs: lkdtm: Modernize and improve details docs: deprecated.rst: Expand str*cpy() replacement notes docs/cpu-load: format the example code.
This commit is contained in:
commit
c80e42a496
@ -61,43 +61,46 @@ will lead to quite erratic information inside ``/proc/stat``::
|
||||
|
||||
static volatile sig_atomic_t stop;
|
||||
|
||||
static void sighandler (int signr)
|
||||
static void sighandler(int signr)
|
||||
{
|
||||
(void) signr;
|
||||
stop = 1;
|
||||
(void) signr;
|
||||
stop = 1;
|
||||
}
|
||||
|
||||
static unsigned long hog (unsigned long niters)
|
||||
{
|
||||
stop = 0;
|
||||
while (!stop && --niters);
|
||||
return niters;
|
||||
stop = 0;
|
||||
while (!stop && --niters);
|
||||
return niters;
|
||||
}
|
||||
|
||||
int main (void)
|
||||
{
|
||||
int i;
|
||||
struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 },
|
||||
.it_value = { .tv_sec = 0, .tv_usec = 1 } };
|
||||
sigset_t set;
|
||||
unsigned long v[HIST];
|
||||
double tmp = 0.0;
|
||||
unsigned long n;
|
||||
signal (SIGALRM, &sighandler);
|
||||
setitimer (ITIMER_REAL, &it, NULL);
|
||||
int i;
|
||||
struct itimerval it = {
|
||||
.it_interval = { .tv_sec = 0, .tv_usec = 1 },
|
||||
.it_value = { .tv_sec = 0, .tv_usec = 1 } };
|
||||
sigset_t set;
|
||||
unsigned long v[HIST];
|
||||
double tmp = 0.0;
|
||||
unsigned long n;
|
||||
signal(SIGALRM, &sighandler);
|
||||
setitimer(ITIMER_REAL, &it, NULL);
|
||||
|
||||
hog (ULONG_MAX);
|
||||
for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog (ULONG_MAX);
|
||||
for (i = 0; i < HIST; ++i) tmp += v[i];
|
||||
tmp /= HIST;
|
||||
n = tmp - (tmp / 3.0);
|
||||
hog (ULONG_MAX);
|
||||
for (i = 0; i < HIST; ++i) v[i] = ULONG_MAX - hog(ULONG_MAX);
|
||||
for (i = 0; i < HIST; ++i) tmp += v[i];
|
||||
tmp /= HIST;
|
||||
n = tmp - (tmp / 3.0);
|
||||
|
||||
sigemptyset (&set);
|
||||
sigaddset (&set, SIGALRM);
|
||||
sigemptyset(&set);
|
||||
sigaddset(&set, SIGALRM);
|
||||
|
||||
for (;;) {
|
||||
hog (n);
|
||||
sigwait (&set, &i);
|
||||
}
|
||||
return 0;
|
||||
for (;;) {
|
||||
hog(n);
|
||||
sigwait(&set, &i);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
|
@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm:
|
||||
- admin_reserve_kbytes
|
||||
- block_dump
|
||||
- compact_memory
|
||||
- compaction_proactiveness
|
||||
- compact_unevictable_allowed
|
||||
- dirty_background_bytes
|
||||
- dirty_background_ratio
|
||||
@ -37,6 +38,7 @@ Currently, these files are in /proc/sys/vm:
|
||||
- dirty_writeback_centisecs
|
||||
- drop_caches
|
||||
- extfrag_threshold
|
||||
- highmem_is_dirtyable
|
||||
- hugetlb_shm_group
|
||||
- laptop_mode
|
||||
- legacy_va_layout
|
||||
|
@ -1,3 +1,5 @@
|
||||
.. _hugetlbpage_index:
|
||||
|
||||
====================
|
||||
HugeTLBpage on ARM64
|
||||
====================
|
||||
|
@ -77,7 +77,6 @@ available subsections can be seen below.
|
||||
console
|
||||
dcdbas
|
||||
eisa
|
||||
ipmb
|
||||
isa
|
||||
isapnp
|
||||
io-mapping
|
||||
|
@ -1,16 +1,19 @@
|
||||
===============
|
||||
Provoke crashes
|
||||
===============
|
||||
.. SPDX-License-Identifier: GPL-2.0
|
||||
|
||||
The lkdtm module provides an interface to crash or injure the kernel at
|
||||
predefined crashpoints to evaluate the reliability of crash dumps obtained
|
||||
using different dumping solutions. The module uses KPROBEs to instrument
|
||||
crashing points, but can also crash the kernel directly without KRPOBE
|
||||
support.
|
||||
============================================================
|
||||
Provoking crashes with Linux Kernel Dump Test Module (LKDTM)
|
||||
============================================================
|
||||
|
||||
The lkdtm module provides an interface to disrupt (and usually crash)
|
||||
the kernel at predefined code locations to evaluate the reliability of
|
||||
the kernel's exception handling and to test crash dumps obtained using
|
||||
different dumping solutions. The module uses KPROBEs to instrument the
|
||||
trigger location, but can also trigger the kernel directly without KPROBE
|
||||
support via debugfs.
|
||||
|
||||
You can provide the way either through module arguments when inserting
|
||||
the module, or through a debugfs interface.
|
||||
You can select the location of the trigger ("crash point name") and the
|
||||
type of action ("crash point type") either through module arguments when
|
||||
inserting the module, or through the debugfs interface.
|
||||
|
||||
Usage::
|
||||
|
||||
@ -18,31 +21,38 @@ Usage::
|
||||
[cpoint_count={>0}]
|
||||
|
||||
recur_count
|
||||
Recursion level for the stack overflow test. Default is 10.
|
||||
Recursion level for the stack overflow test. By default this is
|
||||
dynamically calculated based on kernel configuration, with the
|
||||
goal of being just large enough to exhaust the kernel stack. The
|
||||
value can be seen at `/sys/module/lkdtm/parameters/recur_count`.
|
||||
|
||||
cpoint_name
|
||||
Crash point where the kernel is to be crashed. It can be
|
||||
Where in the kernel to trigger the action. It can be
|
||||
one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY,
|
||||
FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD,
|
||||
IDE_CORE_CP, DIRECT
|
||||
IDE_CORE_CP, or DIRECT
|
||||
|
||||
cpoint_type
|
||||
Indicates the action to be taken on hitting the crash point.
|
||||
It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW,
|
||||
CORRUPT_STACK, UNALIGNED_LOAD_STORE_WRITE, OVERWRITE_ALLOCATION,
|
||||
WRITE_AFTER_FREE,
|
||||
These are numerous, and best queried directly from debugfs. Some
|
||||
of the common ones are PANIC, BUG, EXCEPTION, LOOP, and OVERFLOW.
|
||||
See the contents of `/sys/kernel/debug/provoke-crash/DIRECT` for
|
||||
a complete list.
|
||||
|
||||
cpoint_count
|
||||
Indicates the number of times the crash point is to be hit
|
||||
to trigger an action. The default is 10.
|
||||
before triggering the action. The default is 10 (except for
|
||||
DIRECT, which always fires immediately).
|
||||
|
||||
You can also induce failures by mounting debugfs and writing the type to
|
||||
<mountpoint>/provoke-crash/<crashpoint>. E.g.::
|
||||
<debugfs>/provoke-crash/<crashpoint>. E.g.::
|
||||
|
||||
mount -t debugfs debugfs /mnt
|
||||
echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY
|
||||
mount -t debugfs debugfs /sys/kernel/debug
|
||||
echo EXCEPTION > /sys/kernel/debug/provoke-crash/INT_HARDWARE_ENTRY
|
||||
|
||||
The special file `DIRECT` will induce the action directly without KPROBE
|
||||
instrumentation. This mode is the only one available when the module is
|
||||
built for a kernel without KPROBEs support::
|
||||
|
||||
A special file is `DIRECT` which will induce the crash directly without
|
||||
KPROBE instrumentation. This mode is the only one available when the module
|
||||
is built on a kernel without KPROBEs support.
|
||||
# Instead of having a BUG kill your shell, have it kill "cat":
|
||||
cat <(echo WRITE_RO) >/sys/kernel/debug/provoke-crash/DIRECT
|
||||
|
@ -106,23 +106,29 @@ NUL or newline terminated.
|
||||
|
||||
strcpy()
|
||||
--------
|
||||
strcpy() performs no bounds checking on the destination
|
||||
buffer. This could result in linear overflows beyond the
|
||||
end of the buffer, leading to all kinds of misbehaviors. While
|
||||
`CONFIG_FORTIFY_SOURCE=y` and various compiler flags help reduce the
|
||||
risk of using this function, there is no good reason to add new uses of
|
||||
this function. The safe replacement is strscpy().
|
||||
strcpy() performs no bounds checking on the destination buffer. This
|
||||
could result in linear overflows beyond the end of the buffer, leading to
|
||||
all kinds of misbehaviors. While `CONFIG_FORTIFY_SOURCE=y` and various
|
||||
compiler flags help reduce the risk of using this function, there is
|
||||
no good reason to add new uses of this function. The safe replacement
|
||||
is strscpy(), though care must be given to any cases where the return
|
||||
value of strcpy() was used, since strscpy() does not return a pointer to
|
||||
the destination, but rather a count of non-NUL bytes copied (or negative
|
||||
errno when it truncates).
|
||||
|
||||
strncpy() on NUL-terminated strings
|
||||
-----------------------------------
|
||||
Use of strncpy() does not guarantee that the destination buffer
|
||||
will be NUL terminated. This can lead to various linear read overflows
|
||||
and other misbehavior due to the missing termination. It also NUL-pads the
|
||||
destination buffer if the source contents are shorter than the destination
|
||||
buffer size, which may be a needless performance penalty for callers using
|
||||
only NUL-terminated strings. The safe replacement is strscpy().
|
||||
(Users of strscpy() still needing NUL-padding should instead
|
||||
use strscpy_pad().)
|
||||
Use of strncpy() does not guarantee that the destination buffer will
|
||||
be NUL terminated. This can lead to various linear read overflows and
|
||||
other misbehavior due to the missing termination. It also NUL-pads
|
||||
the destination buffer if the source contents are shorter than the
|
||||
destination buffer size, which may be a needless performance penalty
|
||||
for callers using only NUL-terminated strings. The safe replacement is
|
||||
strscpy(), though care must be given to any cases where the return value
|
||||
of strncpy() was used, since strscpy() does not return a pointer to the
|
||||
destination, but rather a count of non-NUL bytes copied (or negative
|
||||
errno when it truncates). Any cases still needing NUL-padding should
|
||||
instead use strscpy_pad().
|
||||
|
||||
If a caller is using non-NUL-terminated strings, strncpy() can
|
||||
still be used, but destinations should be marked with the `__nonstring
|
||||
@ -131,10 +137,12 @@ attribute to avoid future compiler warnings.
|
||||
|
||||
strlcpy()
|
||||
---------
|
||||
strlcpy() reads the entire source buffer first, possibly exceeding
|
||||
the given limit of bytes to copy. This is inefficient and can lead to
|
||||
linear read overflows if a source string is not NUL-terminated. The
|
||||
safe replacement is strscpy().
|
||||
strlcpy() reads the entire source buffer first (since the return value
|
||||
is meant to match that of strlen()). This read may exceed the destination
|
||||
size limit. This is both inefficient and can lead to linear read overflows
|
||||
if a source string is not NUL-terminated. The safe replacement is strscpy(),
|
||||
though care must be given to any cases where the return value of strlcpy()
|
||||
is used, since strscpy() will return negative errno values when it truncates.
|
||||
|
||||
%p format specifier
|
||||
-------------------
|
||||
|
@ -527,6 +527,13 @@ done on the patch. Reviewed-by: tags, when supplied by reviewers known to
|
||||
understand the subject area and to perform thorough reviews, will normally
|
||||
increase the likelihood of your patch getting into the kernel.
|
||||
|
||||
Both Tested-by and Reviewed-by tags, once received on mailing list from tester
|
||||
or reviewer, should be added by author to the applicable patches when sending
|
||||
next versions. However if the patch has changed substantially in following
|
||||
version, these tags might not be applicable anymore and thus should be removed.
|
||||
Usually removal of someone's Tested-by or Reviewed-by tags should be mentioned
|
||||
in the patch changelog (after the '---' separator).
|
||||
|
||||
A Suggested-by: tag indicates that the patch idea is suggested by the person
|
||||
named and ensures credit to the person for the idea. Please note that this
|
||||
tag should not be added without the reporter's permission, especially if the
|
||||
|
45
Documentation/translations/zh_CN/arm64/hugetlbpage.rst
Normal file
45
Documentation/translations/zh_CN/arm64/hugetlbpage.rst
Normal file
@ -0,0 +1,45 @@
|
||||
.. include:: ../disclaimer-zh_CN.rst
|
||||
|
||||
:Original: :ref:`Documentation/arm64/hugetlbpage.rst <hugetlbpage_index>`
|
||||
|
||||
Translator: Bailu Lin <bailu.lin@vivo.com>
|
||||
|
||||
=====================
|
||||
ARM64中的 HugeTLBpage
|
||||
=====================
|
||||
|
||||
大页依靠有效利用 TLBs 来提高地址翻译的性能。这取决于以下
|
||||
两点 -
|
||||
|
||||
- 大页的大小
|
||||
- TLBs 支持的条目大小
|
||||
|
||||
ARM64 接口支持2种大页方式。
|
||||
|
||||
1) pud/pmd 级别的块映射
|
||||
-----------------------
|
||||
|
||||
这是常规大页,他们的 pmd 或 pud 页面表条目指向一个内存块。
|
||||
不管 TLB 中支持的条目大小如何,块映射可以减少翻译大页地址
|
||||
所需遍历的页表深度。
|
||||
|
||||
2) 使用连续位
|
||||
-------------
|
||||
|
||||
架构中转换页表条目(D4.5.3, ARM DDI 0487C.a)中提供一个连续
|
||||
位告诉 MMU 这个条目是一个连续条目集的一员,它可以被缓存在单
|
||||
个 TLB 条目中。
|
||||
|
||||
在 Linux 中连续位用来增加 pmd 和 pte(最后一级)级别映射的大
|
||||
小。受支持的连续页表条目数量因页面大小和页表级别而异。
|
||||
|
||||
|
||||
支持以下大页尺寸配置 -
|
||||
|
||||
====== ======== ==== ======== ===
|
||||
- CONT PTE PMD CONT PMD PUD
|
||||
====== ======== ==== ======== ===
|
||||
4K: 64K 2M 32M 1G
|
||||
16K: 2M 32M 1G
|
||||
64K: 2M 512M 16G
|
||||
====== ======== ==== ======== ===
|
@ -14,3 +14,4 @@ ARM64 架构
|
||||
:maxdepth: 2
|
||||
|
||||
amu
|
||||
hugetlbpage
|
||||
|
@ -89,7 +89,7 @@ they are write protected for COW (other case of B apply too).
|
||||
|
||||
So here because at time N+2 the clear page table entry was not pair with a
|
||||
notification to invalidate the secondary TLB, the device see the new value for
|
||||
addrB before seing the new value for addrA. This break total memory ordering
|
||||
addrB before seeing the new value for addrA. This break total memory ordering
|
||||
for the device.
|
||||
|
||||
When changing a pte to write protect or to point to a new write protected page
|
||||
|
@ -99,7 +99,7 @@ Steps:
|
||||
2. Ensure that writeback is complete.
|
||||
|
||||
3. Lock the new page that we want to move to. It is locked so that accesses to
|
||||
this (not yet uptodate) page immediately block while the move is in progress.
|
||||
this (not yet up-to-date) page immediately block while the move is in progress.
|
||||
|
||||
4. All the page table references to the page are converted to migration
|
||||
entries. This decreases the mapcount of a page. If the resulting
|
||||
|
@ -18,7 +18,7 @@ Although we already have tracepoint for tracing page allocation/free,
|
||||
using it for analyzing who allocate each page is rather complex. We need
|
||||
to enlarge the trace buffer for preventing overlapping until userspace
|
||||
program launched. And, launched program continually dump out the trace
|
||||
buffer for later analysis and it would change system behviour with more
|
||||
buffer for later analysis and it would change system behaviour with more
|
||||
possibility rather than just keeping it in memory, so bad for debugging.
|
||||
|
||||
page owner can also be used for various purposes. For example, accurate
|
||||
|
@ -378,7 +378,7 @@ c) Execute ``slabinfo-gnuplot.sh`` in '-t' mode, passing all of the
|
||||
can go unnoticed. To deal with that, ``slabinfo-gnuplot.sh`` has two
|
||||
options to 'zoom-in'/'zoom-out':
|
||||
|
||||
a) ``-s %d,%d`` -- overwrites the default image width and heigh
|
||||
a) ``-s %d,%d`` -- overwrites the default image width and height
|
||||
b) ``-r %d,%d`` -- specifies a range of samples to use (for example,
|
||||
in ``slabinfo -X >> FOO_STATS; sleep 1;`` case, using a ``-r
|
||||
40,60`` range will plot only samples collected between 40th and
|
||||
|
@ -19,7 +19,7 @@ Complete virtual memory map with 4-level page tables
|
||||
Note that as we get closer to the top of the address space, the notation changes
|
||||
from TB to GB and then MB/KB.
|
||||
|
||||
- "16M TB" might look weird at first sight, but it's an easier to visualize size
|
||||
- "16M TB" might look weird at first sight, but it's an easier way to visualize size
|
||||
notation than "16 EB", which few will recognize at first sight as 16 exabytes.
|
||||
It also shows it nicely how incredibly large 64-bit address space is.
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user