| Commit message (Collapse) | Author | Age | Files | Lines |
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Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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In support of a soon to be published MFD driver using serdev to talk to
a supervisory processor that uses the CCITT-FALSE CRC16 variant in it's
protocol, this patch was tested successfully on an i.MX6 ARM platform.
Link: http://lkml.kernel.org/r/20170413142932.27287-1-andrew.smirnov@gmail.com
Signed-off-by: Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Allow hash tables to scale with memory but at slower pace, when HASH_ADAPT
is provided every time memory quadruples the sizes of hash tables will
only double instead of quadrupling as well. This algorithm starts working
only when memory size reaches a certain point, currently set to 64G.
This is example of dentry hash table size, before and after four various
memory configurations:
MEMORY SCALE HASH_SIZE
old new old new
8G 13 13 8M 8M
16G 13 13 16M 16M
32G 13 13 32M 32M
64G 13 13 64M 64M
128G 13 14 128M 64M
256G 13 14 256M 128M
512G 13 15 512M 128M
1024G 13 15 1024M 256M
2048G 13 16 2048M 256M
4096G 13 16 4096M 512M
8192G 13 17 8192M 512M
16384G 13 17 16384M 1024M
32768G 13 18 32768M 1024M
65536G 13 18 65536M 2048M
Link: http://lkml.kernel.org/r/1488432825-92126-5-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Babu Moger <babu.moger@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Update dcache, inode, pid, mountpoint, and mount hash tables to use
HASH_ZERO, and remove initialization after allocations. In case of places
where HASH_EARLY was used such as in __pv_init_lock_hash the zeroed hash
table was already assumed, because memblock zeroes the memory.
CPU: SPARC M6, Memory: 7T
Before fix:
Dentry cache hash table entries: 1073741824
Inode-cache hash table entries: 536870912
Mount-cache hash table entries: 16777216
Mountpoint-cache hash table entries: 16777216
ftrace: allocating 20414 entries in 40 pages
Total time: 11.798s
After fix:
Dentry cache hash table entries: 1073741824
Inode-cache hash table entries: 536870912
Mount-cache hash table entries: 16777216
Mountpoint-cache hash table entries: 16777216
ftrace: allocating 20414 entries in 40 pages
Total time: 3.198s
CPU: Intel Xeon E5-2630, Memory: 2.2T:
Before fix:
Dentry cache hash table entries: 536870912
Inode-cache hash table entries: 268435456
Mount-cache hash table entries: 8388608
Mountpoint-cache hash table entries: 8388608
CPU: Physical Processor ID: 0
Total time: 3.245s
After fix:
Dentry cache hash table entries: 536870912
Inode-cache hash table entries: 268435456
Mount-cache hash table entries: 8388608
Mountpoint-cache hash table entries: 8388608
CPU: Physical Processor ID: 0
Total time: 3.244s
Link: http://lkml.kernel.org/r/1488432825-92126-4-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add a new flag HASH_ZERO which when provided grantees that the hash table
that is returned by alloc_large_system_hash() is zeroed. In most cases
that is what is needed by the caller. Use page level allocator's
__GFP_ZERO flags to zero the memory. It is using memset() which is
efficient method to zero memory and is optimized for most platforms.
Link: http://lkml.kernel.org/r/1488432825-92126-3-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Early in boot Linux patches memset and memcpy to branch to platform
optimized versions of these routines. The NG4 (Niagra 4) versions are
currently used on all platforms starting from T4. Recently, there were M7
optimized routines added into UEK4 but not into mainline yet. So, even
with M7 optimized routines NG4 are still going to be used on T4, T5, M5,
and M6 processors.
While investigating how to improve initialization time of dentry_hashtable
which is 8G long on M6 ldom with 7T of main memory, I noticed that
memset() does not reset all the memory in this array, after studying the
code, I realized that NG4memset() branches use %icc register instead of
%xcc to check compare, so if value of length is over 32-bit long, which is
true for 8G array, these routines fail to work properly.
The fix is to replace all %icc with %xcc in these routines. (Alternative
is to use %ncc, but this is misleading, as the code already has sparcv9
only instructions, and cannot be compiled on 32-bit).
This is important to fix this bug, because even older T4-4 can have 2T of
memory, and there are large memory proportional data structures in kernel
which can be larger than 4G in size. The failing of memset() is silent
and corruption is hard to detect.
Link: http://lkml.kernel.org/r/1488432825-92126-2-git-send-email-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Babu Moger <babu.moger@oracle.com>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Fix Kconfig warning in drivers/soc/imx/Kconfig and subsequent build errors
elsewhere when CONFIG_PM is not enabled.
warning: (IMX7_PM_DOMAINS) selects PM_GENERIC_DOMAINS which has unmet direct dependencies (PM)
This warning causes multiple build errors in drivers/base/power/domain.c:
../drivers/base/power/domain.c: In function 'genpd_queue_power_off_work':
../drivers/base/power/domain.c:279:13: error: 'pm_wq' undeclared (first use in this function)
queue_work(pm_wq, &genpd->power_off_work);
../drivers/base/power/domain.c: In function 'genpd_dev_pm_qos_notifier':
../drivers/base/power/domain.c:462:25: error: 'struct dev_pm_info' has no member named 'ignore_children'
if (!dev || dev->power.ignore_children)
../drivers/base/power/domain.c: In function 'rtpm_status_str':
../drivers/base/power/domain.c:2207:16: error: 'struct dev_pm_info' has no member named 'runtime_error'
if (dev->power.runtime_error)
../drivers/base/power/domain.c:2209:21: error: 'struct dev_pm_info' has no member named 'disable_depth'
else if (dev->power.disable_depth)
../drivers/base/power/domain.c:2211:21: error: 'struct dev_pm_info' has no member named 'runtime_status'
else if (dev->power.runtime_status < ARRAY_SIZE(status_lookup))
p = status_lookup[dev->power.runtime_status];
Link: http://lkml.kernel.org/r/47fc2167-bf0a-866a-e075-8247a10aa6e0@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <kernel@pengutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This changes the struct + trailing data pattern to using a void * so that
the end of sem_array is found without possibly indexing past the end which
can upset some static analyzers. Mostly, this ends up avoiding a cast
between different non-void types, which the future randstruct GCC plugin
was warning about.
Link: http://lkml.kernel.org/r/20170508222345.GA52073@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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fail-nth interface is only created in /proc/self/task/<current-tid>/.
This change also adds it in /proc/<pid>/.
This makes shell based tool a bit simpler.
$ bash -c "builtin echo 100 > /proc/self/fail-nth && exec ls /"
Link: http://lkml.kernel.org/r/1491490561-10485-6-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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This fixes fault-inject-simplify-access-check-for-fail-nth.patch in -mm
tree which by mistake partially reverts the change by fault-inject-
parse-as-natural-1-based-value-for-fail-nth-write-interface.patch.
Link: http://lkml.kernel.org/r/1492444483-9239-1-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The fail-nth file is created with 0666 and the access is permitted if
and only if the task is current.
This file is owned by the currnet user. So we can create it with 0644 and
allow the owner to write it. This enables to watch the status of
task->fail_nth from another processes.
Link: http://lkml.kernel.org/r/1491490561-10485-5-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The read interface for fail-nth looks a bit odd. Read from this file
returns "NYYYY..." or "YYYYY..." (this makes me surprise when cat this
file). Because there is no EOF condition. The first character indicates
current->fail_nth is zero or not, and then current->fail_nth is reset to
zero.
Just returning task->fail_nth value is more natural to understand.
Link: http://lkml.kernel.org/r/1491490561-10485-4-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The value written to fail-nth file is parsed as 0-based. Parsing as
one-based is more natural to understand and it enables to cancel the
previous setup by simply writing '0'.
This change also converts task->fail_nth from signed to unsigned int.
Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Automatically detect the number base to use when writing to fail-nth file
instead of always parsing as a decimal number.
Link: http://lkml.kernel.org/r/1491490561-10485-2-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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fix build
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add /proc/self/task/<current-tid>/fail-nth file that allows failing
0-th, 1-st, 2-nd and so on calls systematically.
Excerpt from the added documentation:
===
Write to this file of integer N makes N-th call in the current task fail
(N is 0-based). Read from this file returns a single char 'Y' or 'N'
that says if the fault setup with a previous write to this file was
injected or not, and disables the fault if it wasn't yet injected.
Note that this file enables all types of faults (slab, futex, etc).
This setting takes precedence over all other generic settings like
probability, interval, times, etc. But per-capability settings
(e.g. fail_futex/ignore-private) take precedence over it.
This feature is intended for systematic testing of faults in a single
system call. See an example below.
===
Why adding new setting:
1. Existing settings are global rather than per-task.
So parallel testing is not possible.
2. attr->interval is close but it depends on attr->count
which is non reset to 0, so interval does not work as expected.
3. Trying to model this with existing settings requires manipulations
of all of probability, interval, times, space, task-filter and
unexposed count and per-task make-it-fail files.
4. Existing settings are per-failure-type, and the set of failure
types is potentially expanding.
5. make-it-fail can't be changed by unprivileged user and aggressive
stress testing better be done from an unprivileged user.
Similarly, this would require opening the debugfs files to the
unprivileged user, as he would need to reopen at least times file
(not possible to pre-open before dropping privs).
The proposed interface solves all of the above (see the example).
We want to integrate this into syzkaller fuzzer. A prototype has found 10
bugs in kernel in first day of usage:
https://groups.google.com/forum/#!searchin/syzkaller/%22FAULT_INJECTION%22%7Csort:relevance
Link: http://lkml.kernel.org/r/20170328130128.101773-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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move `struct device' forward declaration to top-of-file
Cc: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Add devm_* wrapper around register_reboot_notifier to simplify device
specific reboot notifier registration/unregistration.
Link: http://lkml.kernel.org/r/20170320171753.1705-1-andrew.smirnov@gmail.com
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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With current epoll architecture target files are addressed with
file_struct and file descriptor number, where the last is not unique.
Moreover files can be transferred from another process via unix socket,
added into queue and closed then so we won't find this descriptor in the
task fdinfo list.
Thus to checkpoint and restore such processes CRIU needs to find out where
exactly the target file is present to add it into epoll queue. For this
sake one can use kcmp call where some particular target file from the
queue is compared with arbitrary file passed as an argument.
Because epoll target files can have same file descriptor number but
different file_struct a caller should explicitly specify the offset
within.
To test if some particular file is matching entry inside
epoll one have to
- fill kcmp_epoll_slot structure with epoll file descriptor,
target file number and target file offset (in case if only
one target is present then it should be 0)
- call kcmp as kcmp(pid1, pid2, KCMP_EPOLL_TFD, fd, &kcmp_epoll_slot)
- the kernel fetch file pointer matching file descriptor @fd of pid1
- lookups for file struct in epoll queue of pid2 and returns traditional
0,1,2 result for sorting purpose
Link: http://lkml.kernel.org/r/20170424154423.511592110@gmail.com
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrey Vagin <avagin@openvz.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Since it is possbile to have same number in tfd field (say file added,
closed, then nother file dup'ed to same number and added back) it is
imposible to distinguish such target files solely by their numbers.
Strictly speaking regular applications don't need to recognize these
targets at all but for checkpoint/restore sake we need to collect targets
to be able to push them back on restore stage in a proper order.
Thus lets add file position, inode and device number where this target
lays. This three fields can be used as a primary key for sorting, and
together with kcmp help CRIU can find out an exact file target (from the
whole set of processes being checkpointed).
Link: http://lkml.kernel.org/r/20170424154423.436491881@gmail.com
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrei Vagin <avagin@virtuozzo.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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lx-fdtdump dumps the flattened device tree passed to the kernel from the
bootloader to the filename specified as the command argument. If no
argument is provided it defaults to fdtdump.dtb. This then allows further
post processing on the machine running GDB. The fdt header is also also
printed in the GDB console. For example:
(gdb) lx-fdtdump
fdt_magic: 0xD00DFEED
fdt_totalsize: 0xC108
off_dt_struct: 0x38
off_dt_strings: 0x3804
off_mem_rsvmap: 0x28
version: 17
last_comp_version: 16
Dumped fdt to fdtdump.dtb
>fdtdump fdtdump.dtb | less
This command is useful as the bootloader can often re-write parts of the
device tree, and this can sometimes cause the kernel to not boot.
Link: http://lkml.kernel.org/r/1481280065-5336-2-git-send-email-kbingham@kernel.org
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Kieran Bingham <kbingham@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Mount fails if file system image has empty files because of sanity check
while reading superblock. For empty files disk offset to end of file
(i_eoffset) is cpu_to_le32(-1). Sanity check comparison, which compares
disk offset with file system size isn't valid for this value and hence is
ignored with this patch.
Steps to reproduce:
$ dd if=/dev/zero of=bfs-image count=204800
$ mkfs.bfs bfs-image
$ mkdir bfs-mount-point
$ sudo mount -t bfs -o loop bfs-image bfs-mount-point/
$ cd bfs-mount-point/
$ sudo touch a
$ cd ..
$ sudo umount bfs-mount-point/
$ sudo mount -t bfs -o loop bfs-image bfs-mount-point/
mount: /dev/loop0: can't read superblock
$ dmesg
[25526.689580] BFS-fs: bfs_fill_super(): Inode 0x00000003 corrupted
Tigran said:
: If you had created the filesystem with the proper mkfs under SCO UnixWare
: 7 you (probably) wouldn't encounter this issue. But since commercial
: Unix-es are now part of history and the only proper way is the Linux
: mkfs.bfs utility, your patch is fine.
Link: http://lkml.kernel.org/r/20170505201625.GA3097@hercules.tuxera.com
Signed-off-by: Rakesh Pandit <rakesh@tuxera.com>
Acked-by: Tigran Aivazian <aivazian.tigran@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Include <stddef.h> (guarded by #ifndef __KERNEL__) to fix the following
linux/sysctl.h userspace compilation errors:
/usr/include/linux/sysctl.h:38:2: error: unknown type name 'size_t'
size_t *oldlenp;
/usr/include/linux/sysctl.h:40:2: error: unknown type name 'size_t'
size_t newlen;
This also fixes userspace compilation of uapi headers that include
linux/sysctl.h, e.g. linux/netfilter.h.
Link: http://lkml.kernel.org/r/20170222230652.GA14373@altlinux.org
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently, VMCOREINFO note information reports the virtual address of
phys_base that is assigned to symbol phys_base. But this doesn't make
sense because to refer to phys_base, it's necessary to get the value of
phys_base itself we are now about to refer to.
Userland tools related to kdump such as makedumpfile and crash utility so
far have made some efforts to calculate phys_base on crash dump formats
generated by mechanisms running outside Linux kernel, such as virtual
machine hypervisor such as qemu dump, which ordinary users use via virsh
dump, or ones implemented on vendor specific firmware.
That is, find a kernel data whose virtual and physical addresses are
available via its note information and calculate phys_base from it.
However, such data structure is not the one prepared for phys_base
purpose. There's no guarantee that other crash dump mechanisms include
such information that can be used to calculate phys_base similarly.
To get VMCOREINFO in vmcore, it's easy to use strings and grep commands
like this; VMCOREINFO consists of simple string:
$ strings vmcore-3.10.0-121.el7.x86_64 | grep -E ".*VMCOREINFO.*" -A 100
VMCOREINFO
OSRELEASE=3.10.0-121.el7.x86_64
PAGESIZE=4096
...
This is also useful to get value of phys_base in kdump 2nd kernel
contained in vmcore using the above-mentioned external crash dump
mechanism; kdump 2nd kernel is an inherently relocated kernel.
This commit doesn't remove VMCOREINFO_SYMBOL(phys_base) line because
makedumpfile refers to it and if removing it, old versions makedumpfile
doesn't work well.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: Dave Anderson <anderson@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Currently vmcoreinfo data is updated at boot time subsys_initcall(), it
has the risk of being modified by some wrong code during system is
running.
As a result, vmcore dumped may contain the wrong vmcoreinfo. Later on,
when using "crash", "makedumpfile", etc utility to parse this vmcore, we
probably will get "Segmentation fault" or other unexpected errors.
E.g. 1) wrong code overwrites vmcoreinfo_data; 2) further crashes the
system; 3) trigger kdump, then we obviously will fail to recognize the
crash context correctly due to the corrupted vmcoreinfo.
Now except for vmcoreinfo, all the crash data is well protected(including
the cpu note which is fully updated in the crash path, thus its
correctness is guaranteed). Given that vmcoreinfo data is a large chunk
prepared for kdump, we better protect it as well.
To solve this, we relocate and copy vmcoreinfo_data to the crash memory
when kdump is loading via kexec syscalls. Because the whole crash memory
will be protected by existing arch_kexec_protect_crashkres() mechanism, we
naturally protect vmcoreinfo_data from write(even read) access under
kernel direct mapping after kdump is loaded.
Since kdump is usually loaded at the very early stage after boot, we can
trust the correctness of the vmcoreinfo data copied.
On the other hand, we still need to operate the vmcoreinfo safe copy when
crash happens to generate vmcoreinfo_note again, we rely on vmap() to map
out a new kernel virtual address and update to use this new one instead in
the following crash_save_vmcoreinfo().
BTW, we do not touch vmcoreinfo_note, because it will be fully updated
using the protected vmcoreinfo_data after crash which is surely correct
just like the cpu crash note.
Link: http://lkml.kernel.org/r/1493281021-20737-3-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we
should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE.
Like explained in commit 77019967f06b ("kdump: fix exported size of
vmcoreinfo note"), it should not affect the actual function, but we better
fix it, also this change should be safe and backward compatible.
After this, we can get rid of variable vmcoreinfo_max_size, let's use the
corresponding macros directly, fewer variables means more safety for
vmcoreinfo operation.
Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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As Eric said,
"what we need to do is move the variable vmcoreinfo_note out
of the kernel's .bss section. And modify the code to regenerate
and keep this information in something like the control page.
Definitely something like this needs a page all to itself, and ideally far
away from any other kernel data structures. I clearly was not watching
closely the data someone decided to keep this silly thing in the kernel's
.bss section."
This patch allocates extra pages for these vmcoreinfo_XXX variables, one
advantage is that it enhances some safety of vmcoreinfo, because
vmcoreinfo now is kept far away from other kernel data structures.
Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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We've encountered zombies that are waiting for a thread to exit that are
looping in ep_poll() almost endlessly although there is a pending SIGKILL
as a result of a group exit.
This happens because we always find ep_events_available() and fetch more
events and never are able to check for signal_pending() that would break
from the loop and return -EINTR.
Special case fatal signals and break immediately to guarantee that we loop
to fetch more events and delay making a timely exit.
It would also be possible to simply move the check for signal_pending()
higher than checking for ep_events_available(), but there have been no
reports of delayed signal handling other than SIGKILL preventing zombies
from exiting that would be fixed by this.
It fixes an issue for us where we have witnessed zombies sticking
around for at least O(minutes), but considering the code has been like
this forever and nobody else has complained that I have found, I would
simply queue it up for 4.12.
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705031722350.76784@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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when walking the zone, we can happens to the holes. we should not
align MAX_ORDER_NR_PAGES, so it can skip the normal memory.
In addition, pagetypeinfo_showmixedcount_print reflect fragmentization.
we hope to get more accurate data. therefore, I decide to fix it.
Link: http://lkml.kernel.org/r/1469502526-24486-2-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When pfn_valid(pfn) returns false, pfn should be aligned with
pageblock_nr_pages other than MAX_ORDER_NR_PAGES in init_pages_in_zone,
because the skipped 2M may be valid pfn, as a result, early allocated
count will not be accurate.
Link: http://lkml.kernel.org/r/1468938136-24228-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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During global reclaim, the nr_reclaimed passed to vmpressure includes
the pages reclaimed from slab. But the corresponding scanned slab
pages is not passed. There is an impact to the vmpressure values
because of this. While moving from kernel version 3.18 to 4.4, a
difference is seen in the vmpressure values for the same workload
resulting in a different behaviour of the vmpressure consumer. One
such case is of a vmpressure based lowmemorykiller. It is observed
that the vmpressure events are received late and less in number
resulting in tasks not being killed at the right time. In this use
case, The number of critical vmpressure events received is around 50%
less on 4.4 than 3.18. The following numbers show the impact on
reclaim activity due to the change in behaviour of lowmemorykiller on a
4GB device. The test launches a number of apps in sequence and repeats
it multiple times. The difference in reclaim behaviour is because of
lesser number of kills and kills happening late, resulting in more
swapping and page cache reclaim.
v4.4 v3.18
pgpgin 163016456 145617236
pgpgout 4366220 4188004
workingset_refault 29857868 26781854
workingset_activate 6293946 5634625
pswpin 1327601 1133912
pswpout 3593842 3229602
pgalloc_dma 99520618 94402970
pgalloc_normal 104046854 98124798
pgfree 203772640 192600737
pgmajfault 2126962 1851836
pgsteal_kswapd_dma 19732899 18039462
pgsteal_kswapd_normal 19945336 17977706
pgsteal_direct_dma 206757 131376
pgsteal_direct_normal 236783 138247
pageoutrun 116622 108370
allocstall 7220 4684
compact_stall 931 856
The lowmemorykiller example above is just for indicating the difference
in vmpressure events between 4.4 and 3.18.
Do not consider reclaimed slab pages for vmpressure calculation. The
reclaimed pages from slab can be excluded because the freeing of a page
by slab shrinking depends on each slab's object population, making the
cost model (i.e. scan:free) different from that of LRU. Also, not
every shrinker accounts the pages it reclaims. Ideally the pages
reclaimed from slab should be passed to vmpressure, otherwise higher
vmpressure levels can be triggered even when there is a reclaim
progress. But accounting only the reclaimed slab pages without the
scanned, and adding something which does not fit into the cost model
just adds noise to the vmpressure values.
Fixes: 6b4f7799c6a5 ("mm: vmscan: invoke slab shrinkers from shrink_zone()")
Link: http://lkml.kernel.org/r/1486641577-11685-2-git-send-email-vinmenon@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Shiraz Hashim <shashim@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The whole memory space is divided into several zones and nodes may have no
page in some zones. In this case, the __absent_pages_in_range() would
return 0, since the range it is searching for is an empty range.
Also this happens more often to those nodes with higher memory range when
there are more nodes, which is a trend for future architectures.
This patch checks the zone range after clamp and adjustment, return 0 if
the range is an empty range.
Link: http://lkml.kernel.org/r/20170206154314.15705-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Standardize the file operation variable names related to all four memory
management /proc interface files. Also change all the symbol permissions
(S_IRUGO) into octal permissions (0444) as it got complaints from
checkpatch.pl. This does not create any functional change to the
interface.
Link: http://lkml.kernel.org/r/20170427030632.8588-1-khandual@linux.vnet.ibm.com
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Until now, we compare just one entry with same checksum when checking
duplication since it is the simplest way to implement. However, for the
completeness, checking all the entries is better so this patch implement
to compare all the entries with same checksum. Since this event would be
rare so there would be no performance loss.
Link: http://lkml.kernel.org/r/1494556204-25796-5-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Benefit of deduplication is dependent on the workload so it's not
preferable to always enable. Therefore, make it optional in Kconfig and
device param. Default is 'off'. This option will be beneficial for users
who use the zram as blockdev and stores build output to it.
Link: http://lkml.kernel.org/r/1494556204-25796-4-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Implement deduplication feature in zram. The purpose of this work is
naturally to save amount of memory usage by zram.
Android is one of the biggest users to use zram as swap and it's really
important to save amount of memory usage. There is a paper that reports
that duplication ratio of Android's memory content is rather high [1].
And, there is a similar work on zswap that also reports that experiments
has shown that around 10-15% of pages stored in zswp are duplicates and
deduplicate them provides some benefits [2].
Also, there is a different kind of workload that uses zram as blockdev and
store build outputs into it to reduce wear-out problem of real blockdev.
In this workload, deduplication hit is very high due to temporary files
and intermediate object files. Detailed analysis is on the bottom of this
description.
Anyway, if we can detect duplicated content and avoid to store duplicated
content at different memory space, we can save memory. This patch tries
to do that.
Implementation is almost simple and intuitive but I should note one thing
about implementation detail.
To check duplication, this patch uses checksum of the page and collision
of this checksum could be possible. There would be many choices to handle
this situation but this patch chooses to allow entry with duplicated
checksum to be added to the hash, but, not to compare all entries with
duplicated checksum when checking duplication. I guess that checksum
collision is quite rare event and we don't need to pay any attention to
such a case. Therefore, I decided the most simplest way to implement the
feature. If there is a different opinion, I can accept and go that way.
Following is the result of this patch.
Test result #1 (Swap):
Android Marshmallow, emulator, x86_64, Backporting to kernel v3.18
orig_data_size: 145297408
compr_data_size: 32408125
mem_used_total: 32276480
dup_data_size: 3188134
meta_data_size: 1444272
Last two metrics added to mm_stat are related to this work. First one,
dup_data_size, is amount of saved memory by avoiding to store duplicated
page. Later one, meta_data_size, is the amount of data structure to
support deduplication. If dup > meta, we can judge that the patch
improves memory usage.
In Adnroid, we can save 5% of memory usage by this work.
Test result #2 (Blockdev):
build the kernel and store output to ext4 FS on zram
<no-dedup>
Elapsed time: 249 s
mm_stat: 430845952 191014886 196898816 0 196898816 28320 0 0 0
<dedup>
Elapsed time: 250 s
mm_stat: 430505984 190971334 148365312 0 148365312 28404 0 47287038 3945792
There is no performance degradation and save 23% memory.
Test result #3 (Blockdev):
copy android build output dir(out/host) to ext4 FS on zram
<no-dedup>
Elapsed time: out/host: 88 s
mm_stat: 8834420736 3658184579 3834208256 0 3834208256 32889 0 0 0
<dedup>
Elapsed time: out/host: 100 s
mm_stat: 8832929792 3657329322 2832015360 0 2832015360 32609 0 952568877 80880336
It shows performance degradation roughly 13% and save 24% memory. Maybe,
it is due to overhead of calculating checksum and comparison.
Test result #4 (Blockdev):
copy android build output dir(out/target/common) to ext4 FS on zram
<no-dedup>
Elapsed time: out/host: 203 s
mm_stat: 4041678848 2310355010 2346577920 0 2346582016 500 4 0 0
<dedup>
Elapsed time: out/host: 201 s
mm_stat: 4041666560 2310488276 1338150912 0 1338150912 476 0 989088794 24564336
Memory is saved by 42% and performance is the same. Even if there is overhead
of calculating checksum and comparison, large hit ratio compensate it since
hit leads to less compression attempt.
I checked the detailed reason of savings on kernel build workload and
there are some cases that deduplication happens.
1) *.cmd
Build command is usually similar in one directory so content of these file
are very similar. In my system, more than 789 lines in fs/ext4/.namei.o.cmd
and fs/ext4/.inode.o.cmd are the same in 944 and 938 lines of the file,
respectively.
2) intermediate object files
built-in.o and temporary object file have the similar contents. More than
50% of fs/ext4/ext4.o is the same with fs/ext4/built-in.o.
3) vmlinux
.tmp_vmlinux1 and .tmp_vmlinux2 and arch/x86/boo/compressed/vmlinux.bin
have the similar contents.
Android test has similar case that some of object files(.class
and .so) are similar with another ones.
(./host/linux-x86/lib/libartd.so and
./host/linux-x86-lib/libartd-comiler.so)
Anyway, benefit seems to be largely dependent on the workload so
following patch will make this feature optional. However, this feature
can help some usecases so is deserved to be merged.
[1]: MemScope: Analyzing Memory Duplication on Android Systems,
dl.acm.org/citation.cfm?id=2797023
[2]: zswap: Optimize compressed pool memory utilization,
lkml.kernel.org/r/1341407574.7551.1471584870761.JavaMail.weblogic@epwas3p2
Link: http://lkml.kernel.org/r/1494556204-25796-3-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The following patch will implement deduplication functionality in zram and
it requires an indirection layer to manage the life cycle of zsmalloc
handle. To prepare that, this patch introduces zram_entry which can be
used to manage the life-cycle of zsmalloc handle. Many lines are changed
due to rename but core change is just simple introduction about newly data
structure.
Link: http://lkml.kernel.org/r/1494556204-25796-2-git-send-email-iamjoonsoo.kim@lge.com
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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If merge_across_nodes was manually set to 0 (not the default value) by the
admin or a tuned profile on NUMA systems triggering cross-NODE page
migrations, a stable_node use after free could materialize.
If the chain is collapsed stable_node would point to the old chain that
was already freed. stable_node_dup would be the stable_node dup now
converted to a regular stable_node and indexed in the rbtree in
replacement of the freed stable_node chain (not anymore a dup).
This special case where the chain is collapsed in the NUMA replacement
path, is now detected by setting stable_node to NULL by the chain_prune
callee if it decides to collapse the chain. This tells the NUMA
replacement code that even if stable_node and stable_node_dup are
different, this is not a chain if stable_node is NULL, as the
stable_node_dup was converted to a regular stable_node and the chain was
collapsed.
It is generally safer for the callee to force the caller stable_node to
NULL the moment it become stale so any other mistake like this would
result in an instant Oops easier to debug than an use after free.
Otherwise the replace logic would act like if stable_node was a valid
chain, when in fact it was freed. Notably
stable_node_chain_add_dup(page_node, stable_node) would run on a stable
stable_node.
Andrey Ryabinin found the source of the use after free in chain_prune().
Link: http://lkml.kernel.org/r/20170512193805.8807-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Without a max deduplication limit for each KSM page, the list of the
rmap_items associated to each stable_node can grow infinitely large.
During the rmap walk each entry can take up to ~10usec to process because
of IPIs for the TLB flushing (both for the primary MMU and the secondary
MMUs with the MMU notifier). With only 16GB of address space shared in
the same KSM page, that would amount to dozens of seconds of kernel
runtime.
A ~256 max deduplication factor will reduce the latencies of the rmap
walks on KSM pages to order of a few msec. Just doing the cond_resched()
during the rmap walks is not enough, the list size must have a limit too,
otherwise the caller could get blocked in (schedule friendly) kernel
computations for seconds, unexpectedly.
There's room for optimization to significantly reduce the IPI delivery
cost during the page_referenced(), but at least for page_migration in the
KSM case (used by hard NUMA bindings, compaction and NUMA balancing) it
may be inevitable to send lots of IPIs if each rmap_item->mm is active on
a different CPU and there are lots of CPUs. Even if we ignore the IPI
delivery cost, we've still to walk the whole KSM rmap list, so we can't
allow millions or billions (ulimited) number of entries in the KSM
stable_node rmap_item lists.
The limit is enforced efficiently by adding a second dimension to the
stable rbtree. So there are three types of stable_nodes: the regular ones
(identical as before, living in the first flat dimension of the stable
rbtree), the "chains" and the "dups".
Every "chain" and all "dups" linked into a "chain" enforce the invariant
that they represent the same write protected memory content, even if each
"dup" will be pointed by a different KSM page copy of that content. This
way the stable rbtree lookup computational complexity is unaffected if
compared to an unlimited max_sharing_limit. It is still enforced that
there cannot be KSM page content duplicates in the stable rbtree itself.
Adding the second dimension to the stable rbtree only after the
max_page_sharing limit hits, provides for a zero memory footprint increase
on 64bit archs. The memory overhead of the per-KSM page stable_tree and
per virtual mapping rmap_item is unchanged. Only after the
max_page_sharing limit hits, we need to allocate a stable_tree "chain" and
rb_replace() the "regular" stable_node with the newly allocated
stable_node "chain". After that we simply add the "regular" stable_node
to the chain as a stable_node "dup" by linking hlist_dup in the
stable_node_chain->hlist. This way the "regular" (flat) stable_node is
converted to a stable_node "dup" living in the second dimension of the
stable rbtree.
During stable rbtree lookups the stable_node "chain" is identified as
stable_node->rmap_hlist_len == STABLE_NODE_CHAIN (aka
is_stable_node_chain()).
When dropping stable_nodes, the stable_node "dup" is identified as
stable_node->head == STABLE_NODE_DUP_HEAD (aka is_stable_node_dup()).
The STABLE_NODE_DUP_HEAD must be an unique valid pointer never used
elsewhere in any stable_node->head/node to avoid a clashes with the
stable_node->node.rb_parent_color pointer, and different from
&migrate_nodes. So the second field of &migrate_nodes is picked and
verified as always safe with a BUILD_BUG_ON in case the list_head
implementation changes in the future.
The STABLE_NODE_DUP is picked as a random negative value in
stable_node->rmap_hlist_len. rmap_hlist_len cannot become negative when
it's a "regular" stable_node or a stable_node "dup".
The stable_node_chain->nid is irrelevant. The stable_node_chain->kpfn is
aliased in a union with a time field used to rate limit the
stable_node_chain->hlist prunes.
The garbage collection of the stable_node_chain happens lazily during
stable rbtree lookups (as for all other kind of stable_nodes), or while
disabling KSM with "echo 2 >/sys/kernel/mm/ksm/run" while collecting the
entire stable rbtree.
While the "regular" stable_nodes and the stable_node "dups" must wait for
their underlying tree_page to be freed before they can be freed
themselves, the stable_node "chains" can be freed immediately if the
stable_node->hlist turns empty. This is because the "chains" are never
pointed by any page->mapping and they're effectively stable rbtree KSM
self contained metadata.
[akpm@linux-foundation.org: fix non-NUMA build]
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Evgheni Dereveanchin <ederevea@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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When start_pfn equals end_pfn, __free_pages_memory() has no effect and
__free_memory_core() will finally return (end_pfn - start_pfn) = 0.
This patch returns 0 directly when start_pfn equals end_pfn.
Link: http://lkml.kernel.org/r/20170502131115.6650-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Clang and its -Wunsequenced emits a warning
mm/vmscan.c:2961:25: error: unsequenced modification and access to
'gfp_mask' [-Wunsequenced]
.gfp_mask = (gfp_mask = current_gfp_context(gfp_mask)),
^
While it is not clear to me whether the initialization code violates the
specification (6.7.8 par 19 (ISO/IEC 9899) looks like it disagrees) the
code is quite confusing and worth cleaning up anyway. Fix this by
reusing sc.gfp_mask rather than the updated input gfp_mask parameter.
Link: http://lkml.kernel.org/r/20170510154030.10720-1-nick.desaulniers@gmail.com
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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The protection map is only modified by per-arch init code so it can be
protected from writes after the init code runs.
This change was extracted from PaX where it's part of KERNEXEC.
Link: http://lkml.kernel.org/r/20170510174441.26163-1-danielmicay@gmail.com
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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There are a number of times that we loop over NR_MEM_SECTIONS, looking for
section_present() on each section. But, when we have very large physical
address spaces (large MAX_PHYSMEM_BITS), NR_MEM_SECTIONS becomes very
large, making the loops quite long.
With MAX_PHYSMEM_BITS=46 and a section size of 128MB, the current loops
are 512k iterations, which we barely notice on modern hardware. But,
raising MAX_PHYSMEM_BITS higher (like we will see on systems that support
5-level paging) makes this 64x longer and we start to notice, especially
on slower systems like simulators. A 10-second delay for 512k iterations
is annoying. But, a 640- second delay is crippling.
This does not help if we have extremely sparse physical address spaces,
but those are quite rare. We expect that most of the "slow" systems where
this matters will also be quite small and non-sparse.
To fix this, we track the highest section we've ever encountered. This
lets us know when we will *never* see another section_present(), and lets
us break out of the loops earlier.
Doing the whole for_each_present_section_nr() macro is probably overkill,
but it will ensure that any future loop iterations that we grow are more
likely to be correct.
Kirrill said "It shaved almost 40 seconds from boot time in qemu with
5-level paging enabled for me".
Link: http://lkml.kernel.org/r/20170504174434.C45A4735@viggo.jf.intel.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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kmem_cache->cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is set,
so wrap it with config CONFIG_SLUB_CPU_PARTIAL will save some space on
32bit arch.
This patch wraps kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL
and wraps its sysfs too.
Link: http://lkml.kernel.org/r/20170502144533.10729-4-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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avoid strange 80-col tricks
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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cpu_slab's field partial is used when CONFIG_SLUB_CPU_PARTIAL is set,
which means we can save a pointer's space on each cpu for every slub item.
This patch wraps cpu_slab->partial in CONFIG_SLUB_CPU_PARTIAL and wraps
its sysfs use too.
Link: http://lkml.kernel.org/r/20170502144533.10729-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Patch series " try to save some memory for kmem_cache in some cases", v2.
kmem_cache is a frequently used data in kernel. During the code reading,
I found maybe we could save some space in some cases.
1. On 64bit arch, type int will occupy a word if it doesn't sit well.
2. cpu_slab->partial is just used when CONFIG_SLUB_CPU_PARTIAL is set
3. cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is set, while
just save some space on 32bit arch.
This patch (of 3):
On 64bit arch, struct is 8-bytes aligned, so int will occupy a word if it
doesn't sit well.
This patch pack red_left_pad with reserved to save 8 bytes for struct
kmem_cache on a 64bit arch.
Link: http://lkml.kernel.org/r/20170502144533.10729-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Each time a slab is deactivated, the page and freelist pointer should be
reset.
This patch just merges these two options into deactivate_slab().
Link: http://lkml.kernel.org/r/20170507031215.3130-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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