08 Oct, 2016
40 commits
-
Git can be told to apply language-specific rules when generating diffs.
Enable this for C source code files (*.c and *.h) so that function names
are printed right. Specifically, doing so prevents "git diff" from
mistakenly considering unindented goto labels as function names.Link: http://lkml.kernel.org/r/20160907143403.1449324f@endymion
Signed-off-by: Jean Delvare
Cc: Peter Zijlstra
Cc: Joe Perches
Cc: Jonathan Corbet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The declarations of arch-specific functions have been moved to a common
header in commit 3820b4d2789f ('uprobes: Move function declarations out
of arch'), but MIPS and S390 has added them to their own trees later.
Remove the unnecessary duplicates.Link: http://lkml.kernel.org/r/1472804384-17830-1-git-send-email-marcin.nowakowski@imgtec.com
Signed-off-by: Marcin Nowakowski
Acked-by: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Ralf Baechle
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
No need to correct the correct.
Link: http://lkml.kernel.org/r/1472490791.3425.38.camel@perches.com
Signed-off-by: Joe Perches
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative. Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Acked-by: Peter Zijlstra (Intel)
Tested-by: Peter Zijlstra (Intel)
Tested-by: Daniel Thompson [arm]
Tested-by: Petr Mladek
Cc: Aaron Tomlin
Cc: Peter Zijlstra (Intel)
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Previously tile was rolling its own method of capturing backtrace data
in the NMI handlers, but it was relying on running printk() from the NMI
handler, which is not always safe. So adopt the nmi_backtrace model
(with the new cpumask extension) instead.So we can call the nmi_backtrace code directly from the nmi handler,
move the nmi_enter()/exit() into the top-level tile NMI handler.The semantics of the routine change slightly since it is now synchronous
with the remote cores completing the backtraces. Previously it was
asynchronous, but with protection to avoid starting a new remote
backtrace if the old one was still in progress.Link: http://lkml.kernel.org/r/1472487169-14923-4-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Cc: Daniel Thompson [arm]
Cc: Petr Mladek
Cc: Aaron Tomlin
Cc: Peter Zijlstra (Intel)
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently on arm there is code that checks whether it should call
dump_stack() explicitly, to avoid trying to raise an NMI when the
current context is not preemptible by the backtrace IPI. Similarly, the
forthcoming arch/tile support uses an IPI mechanism that does not
support generating an NMI to self.Accordingly, move the code that guards this case into the generic
mechanism, and invoke it unconditionally whenever we want a backtrace of
the current cpu. It seems plausible that in all cases, dump_stack()
will generate better information than generating a stack from the NMI
handler. The register state will be missing, but that state is likely
not particularly helpful in any case.Or, if we think it is helpful, we should be capturing and emitting the
current register state in all cases when regs == NULL is passed to
nmi_cpu_backtrace().Link: http://lkml.kernel.org/r/1472487169-14923-3-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Tested-by: Daniel Thompson [arm]
Reviewed-by: Petr Mladek
Acked-by: Aaron Tomlin
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "improvements to the nmi_backtrace code" v9.
This patch series modifies the trigger_xxx_backtrace() NMI-based remote
backtracing code to make it more flexible, and makes a few small
improvements along the way.The motivation comes from the task isolation code, where there are
scenarios where we want to be able to diagnose a case where some cpu is
about to interrupt a task-isolated cpu. It can be helpful to see both
where the interrupting cpu is, and also an approximation of where the
cpu that is being interrupted is. The nmi_backtrace framework allows us
to discover the stack of the interrupted cpu.I've tested that the change works as desired on tile, and build-tested
x86, arm, mips, and sparc64. For x86 I confirmed that the generic
cpuidle stuff as well as the architecture-specific routines are in the
new cpuidle section. For arm, mips, and sparc I just build-tested it
and made sure the generic cpuidle routines were in the new cpuidle
section, but I didn't attempt to figure out which the platform-specific
idle routines might be. That might be more usefully done by someone
with platform experience in follow-up patches.This patch (of 4):
Currently you can only request a backtrace of either all cpus, or all
cpus but yourself. It can also be helpful to request a remote backtrace
of a single cpu, and since we want that, the logical extension is to
support a cpumask as the underlying primitive.This change modifies the existing lib/nmi_backtrace.c code to take a
cpumask as its basic primitive, and modifies the linux/nmi.h code to use
the new "cpumask" method instead.The existing clients of nmi_backtrace (arm and x86) are converted to
using the new cpumask approach in this change.The other users of the backtracing API (sparc64 and mips) are converted
to use the cpumask approach rather than the all/allbutself approach.
The mips code ignored the "include_self" boolean but with this change it
will now also dump a local backtrace if requested.Link: http://lkml.kernel.org/r/1472487169-14923-2-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Tested-by: Daniel Thompson [arm]
Reviewed-by: Aaron Tomlin
Reviewed-by: Petr Mladek
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Ralf Baechle
Cc: David Miller
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently, when min/max are nested within themselves, sparse will warn:
warning: symbol '_min1' shadows an earlier one
originally declared here
warning: symbol '_min1' shadows an earlier one
originally declared here
warning: symbol '_min2' shadows an earlier one
originally declared hereThis also immediately happens when min3() or max3() are used.
Since sparse implements __COUNTER__, we can use __UNIQUE_ID() to
generate unique variable names, avoiding this.Link: http://lkml.kernel.org/r/1471519773-29882-1-git-send-email-johannes@sipsolutions.net
Signed-off-by: Johannes Berg
Cc: Jens Axboe
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Add some more description on the limitations for smaps/maps readings, as
well as some guaruntees we can make.Link: http://lkml.kernel.org/r/1475296958-27652-2-git-send-email-robert.hu@intel.com
Signed-off-by: Robert Ho
Acked-by: Michal Hocko
Cc: Dave Hansen
Cc: Xiao Guangrong
Cc: Robert Hu
Cc: Oleg Nesterov
Cc: Paolo Bonzini
Cc: Dan Williams
Cc: Gleb Natapov
Cc: Marcelo Tosatti
Cc: Stefan Hajnoczi
Cc: Ross Zwisler
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Recently, Redhat reported that nvml test suite failed on QEMU/KVM,
more detailed info please refer to:https://bugzilla.redhat.com/show_bug.cgi?id=1365721
Actually, this bug is not only for NVDIMM/DAX but also for any other
file systems. This simple test case abstracted from nvml can easily
reproduce this bug in common environment:-------------------------- testcase.c -----------------------------
int
is_pmem_proc(const void *addr, size_t len)
{
const char *caddr = addr;FILE *fp;
if ((fp = fopen("/proc/self/smaps", "r")) == NULL) {
printf("!/proc/self/smaps");
return 0;
}int retval = 0; /* assume false until proven otherwise */
char line[PROCMAXLEN]; /* for fgets() */
char *lo = NULL; /* beginning of current range in smaps file */
char *hi = NULL; /* end of current range in smaps file */
int needmm = 0; /* looking for mm flag for current range */
while (fgets(line, PROCMAXLEN, fp) != NULL) {
static const char vmflags[] = "VmFlags:";
static const char mm[] = " wr";/* check for range line */
if (sscanf(line, "%p-%p", &lo, &hi) == 2) {
if (needmm) {
/* last range matched, but no mm flag found */
printf("never found mm flag.\n");
break;
} else if (caddr < lo) {
/* never found the range for caddr */
printf("#######no match for addr %p.\n", caddr);
break;
} else if (caddr < hi) {
/* start address is in this range */
size_t rangelen = (size_t)(hi - caddr);/* remember that matching has started */
needmm = 1;/* calculate remaining range to search for */
if (len > rangelen) {
len -= rangelen;
caddr += rangelen;
printf("matched %zu bytes in range "
"%p-%p, %zu left over.\n",
rangelen, lo, hi, len);
} else {
len = 0;
printf("matched all bytes in range "
"%p-%p.\n", lo, hi);
}
}
} else if (needmm && strncmp(line, vmflags,
sizeof(vmflags) - 1) == 0) {
if (strstr(&line[sizeof(vmflags) - 1], mm) != NULL) {
printf("mm flag found.\n");
if (len == 0) {
/* entire range matched */
retval = 1;
break;
}
needmm = 0; /* saw what was needed */
} else {
/* mm flag not set for some or all of range */
printf("range has no mm flag.\n");
break;
}
}
}fclose(fp);
printf("returning %d.\n", retval);
return retval;
}void *Addr;
size_t Size;/*
* worker -- the work each thread performs
*/
static void *
worker(void *arg)
{
int *ret = (int *)arg;
*ret = is_pmem_proc(Addr, Size);
return NULL;
}int main(int argc, char *argv[])
{
if (argc < 2 || argc > 3) {
printf("usage: %s file [env].\n", argv[0]);
return -1;
}int fd = open(argv[1], O_RDWR);
struct stat stbuf;
fstat(fd, &stbuf);Size = stbuf.st_size;
Addr = mmap(0, stbuf.st_size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);close(fd);
pthread_t threads[NTHREAD];
int ret[NTHREAD];/* kick off NTHREAD threads */
for (int i = 0; i < NTHREAD; i++)
pthread_create(&threads[i], NULL, worker, &ret[i]);/* wait for all the threads to complete */
for (int i = 0; i < NTHREAD; i++)
pthread_join(threads[i], NULL);/* verify that all the threads return the same value */
for (int i = 1; i < NTHREAD; i++) {
if (ret[0] != ret[i]) {
printf("Error i %d ret[0] = %d ret[i] = %d.\n", i,
ret[0], ret[i]);
}
}printf("%d", ret[0]);
return 0;
}It failed as some threads can not find the memory region in
"/proc/self/smaps" which is allocated in the main processIt is caused by proc fs which uses 'file->version' to indicate the VMA that
is the last one has already been handled by read() system call. When the
next read() issues, it uses the 'version' to find the VMA, then the next
VMA is what we want to handle, the related code is as follows:if (last_addr) {
vma = find_vma(mm, last_addr);
if (vma && (vma = m_next_vma(priv, vma)))
return vma;
}However, VMA will be lost if the last VMA is gone, e.g:
The process VMA list is A->B->C->D
CPU 0 CPU 1
read() system call
handle VMA B
version = B
return to userspaceunmap VMA B
issue read() again to continue to get
the region info
find_vma(version) will get VMA C
m_next_vma(C) will get VMA D
handle D
!!! VMA C is lost !!!In order to fix this bug, we make 'file->version' indicate the end address
of the current VMA. m_start will then look up a vma which with vma_start
< last_vm_end and moves on to the next vma if we found the same or an
overlapping vma. This will guarantee that we will not miss an exclusive
vma but we can still miss one if the previous vma was shrunk. This is
acceptable because guaranteeing "never miss a vma" is simply not feasible.
User has to cope with some inconsistencies if the file is not read in one
go.[mhocko@suse.com: changelog fixes]
Link: http://lkml.kernel.org/r/1475296958-27652-1-git-send-email-robert.hu@intel.com
Acked-by: Dave Hansen
Signed-off-by: Xiao Guangrong
Signed-off-by: Robert Hu
Acked-by: Michal Hocko
Acked-by: Oleg Nesterov
Cc: Paolo Bonzini
Cc: Dan Williams
Cc: Gleb Natapov
Cc: Marcelo Tosatti
Cc: Stefan Hajnoczi
Cc: Ross Zwisler
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In changing from checking ptrace_may_access(p, PTRACE_MODE_ATTACH_FSCREDS)
to capable(CAP_SYS_NICE), I missed that ptrace_my_access succeeds when p
== current, but the CAP_SYS_NICE doesn't.Thus while the previous commit was intended to loosen the needed
privileges to modify a processes timerslack, it needlessly restricted a
task modifying its own timerslack via the proc//timerslack_ns
(which is permitted also via the PR_SET_TIMERSLACK method).This patch corrects this by checking if p == current before checking the
CAP_SYS_NICE value.This patch applies on top of my two previous patches currently in -mm
Link: http://lkml.kernel.org/r/1471906870-28624-1-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz
Acked-by: Kees Cook
Cc: "Serge E. Hallyn"
Cc: Thomas Gleixner
Cc: Arjan van de Ven
Cc: Oren Laadan
Cc: Ruchi Kandoi
Cc: Rom Lemarchand
Cc: Todd Kjos
Cc: Colin Cross
Cc: Nick Kralevich
Cc: Dmitry Shmidt
Cc: Elliott Hughes
Cc: Android Kernel Team
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
As requested, this patch checks the existing LSM hooks
task_getscheduler/task_setscheduler when reading or modifying the task's
timerslack value.Previous versions added new get/settimerslack LSM hooks, but since they
checked the same PROCESS__SET/GETSCHED values as existing hooks, it was
suggested we just use the existing ones.Link: http://lkml.kernel.org/r/1469132667-17377-2-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz
Cc: Kees Cook
Cc: "Serge E. Hallyn"
Cc: Thomas Gleixner
Cc: Arjan van de Ven
Cc: Oren Laadan
Cc: Ruchi Kandoi
Cc: Rom Lemarchand
Cc: Todd Kjos
Cc: Colin Cross
Cc: Nick Kralevich
Cc: Dmitry Shmidt
Cc: Elliott Hughes
Cc: James Morris
Cc: Android Kernel Team
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When an interface to allow a task to change another tasks timerslack was
first proposed, it was suggested that something greater then
CAP_SYS_NICE would be needed, as a task could be delayed further then
what normally could be done with nice adjustments.So CAP_SYS_PTRACE was adopted instead for what became the
/proc//timerslack_ns interface. However, for Android (where this
feature originates), giving the system_server CAP_SYS_PTRACE would allow
it to observe and modify all tasks memory. This is considered too high
a privilege level for only needing to change the timerslack.After some discussion, it was realized that a CAP_SYS_NICE process can
set a task as SCHED_FIFO, so they could fork some spinning processes and
set them all SCHED_FIFO 99, in effect delaying all other tasks for an
infinite amount of time.So as a CAP_SYS_NICE task can already cause trouble for other tasks,
using it as a required capability for accessing and modifying
/proc//timerslack_ns seems sufficient.Thus, this patch loosens the capability requirements to CAP_SYS_NICE and
removes CAP_SYS_PTRACE, simplifying some of the code flow as well.This is technically an ABI change, but as the feature just landed in
4.6, I suspect no one is yet using it.Link: http://lkml.kernel.org/r/1469132667-17377-1-git-send-email-john.stultz@linaro.org
Signed-off-by: John Stultz
Reviewed-by: Nick Kralevich
Acked-by: Serge Hallyn
Acked-by: Kees Cook
Cc: Kees Cook
Cc: "Serge E. Hallyn"
Cc: Thomas Gleixner
Cc: Arjan van de Ven
Cc: Oren Laadan
Cc: Ruchi Kandoi
Cc: Rom Lemarchand
Cc: Todd Kjos
Cc: Colin Cross
Cc: Nick Kralevich
Cc: Dmitry Shmidt
Cc: Elliott Hughes
Cc: Android Kernel Team
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Use a specific routine to emit most lines so that the code is easier to
read and maintain.akpm:
text data bss dec hex filename
2976 8 0 2984 ba8 fs/proc/meminfo.o before
2669 8 0 2677 a75 fs/proc/meminfo.o afterLink: http://lkml.kernel.org/r/8fce7fdef2ba081a4ef531594e97da8a9feebb58.1470810406.git.joe@perches.com
Signed-off-by: Joe Perches
Cc: Andi Kleen
Cc: Alexey Dobriyan
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Allow some seq_puts removals by taking a string instead of a single
char.[akpm@linux-foundation.org: update vmstat_show(), per Joe]
Link: http://lkml.kernel.org/r/667e1cf3d436de91a5698170a1e98d882905e956.1470704995.git.joe@perches.com
Signed-off-by: Joe Perches
Cc: Joe Perches
Cc: Andi Kleen
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
top(1) opens the following files for every PID:
/proc/*/stat
/proc/*/statm
/proc/*/statusThis patch switches /proc/*/status away from seq_printf().
The result is 13.5% speedup.Benchmark is open("/proc/self/status")+read+close 1.000.000 million times.
BEFORE
$ perf stat -r 10 taskset -c 3 ./proc-self-statusPerformance counter stats for 'taskset -c 3 ./proc-self-status' (10 runs):
10748.474301 task-clock (msec) # 0.954 CPUs utilized ( +- 0.91% )
12 context-switches # 0.001 K/sec ( +- 1.09% )
1 cpu-migrations # 0.000 K/sec
104 page-faults # 0.010 K/sec ( +- 0.45% )
37,424,127,876 cycles # 3.482 GHz ( +- 0.04% )
8,453,010,029 stalled-cycles-frontend # 22.59% frontend cycles idle ( +- 0.12% )
3,747,609,427 stalled-cycles-backend # 10.01% backend cycles idle ( +- 0.68% )
65,632,764,147 instructions # 1.75 insn per cycle
# 0.13 stalled cycles per insn ( +- 0.00% )
13,981,324,775 branches # 1300.773 M/sec ( +- 0.00% )
138,967,110 branch-misses # 0.99% of all branches ( +- 0.18% )11.263885428 seconds time elapsed ( +- 0.04% )
^^^^^^^^^^^^AFTER
$ perf stat -r 10 taskset -c 3 ./proc-self-statusPerformance counter stats for 'taskset -c 3 ./proc-self-status' (10 runs):
9010.521776 task-clock (msec) # 0.925 CPUs utilized ( +- 1.54% )
11 context-switches # 0.001 K/sec ( +- 1.54% )
1 cpu-migrations # 0.000 K/sec ( +- 11.11% )
103 page-faults # 0.011 K/sec ( +- 0.60% )
32,352,310,603 cycles # 3.591 GHz ( +- 0.07% )
7,849,199,578 stalled-cycles-frontend # 24.26% frontend cycles idle ( +- 0.27% )
3,269,738,842 stalled-cycles-backend # 10.11% backend cycles idle ( +- 0.73% )
56,012,163,567 instructions # 1.73 insn per cycle
# 0.14 stalled cycles per insn ( +- 0.00% )
11,735,778,795 branches # 1302.453 M/sec ( +- 0.00% )
98,084,459 branch-misses # 0.84% of all branches ( +- 0.28% )9.741247736 seconds time elapsed ( +- 0.07% )
^^^^^^^^^^^Link: http://lkml.kernel.org/r/20160806125608.GB1187@p183.telecom.by
Signed-off-by: Alexey Dobriyan
Cc: Joe Perches
Cc: Andi Kleen
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Every current KDE system has process named ksysguardd polling files
below once in several seconds:$ strace -e trace=open -p $(pidof ksysguardd)
Process 1812 attached
open("/etc/mtab", O_RDONLY|O_CLOEXEC) = 8
open("/etc/mtab", O_RDONLY|O_CLOEXEC) = 8
open("/proc/net/dev", O_RDONLY) = 8
open("/proc/net/wireless", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/proc/stat", O_RDONLY) = 8
open("/proc/vmstat", O_RDONLY) = 8Hell knows what it is doing but speed up reading /proc/vmstat by 33%!
Benchmark is open+read+close 1.000.000 times.
BEFORE
$ perf stat -r 10 taskset -c 3 ./proc-vmstatPerformance counter stats for 'taskset -c 3 ./proc-vmstat' (10 runs):
13146.768464 task-clock (msec) # 0.960 CPUs utilized ( +- 0.60% )
15 context-switches # 0.001 K/sec ( +- 1.41% )
1 cpu-migrations # 0.000 K/sec ( +- 11.11% )
104 page-faults # 0.008 K/sec ( +- 0.57% )
45,489,799,349 cycles # 3.460 GHz ( +- 0.03% )
9,970,175,743 stalled-cycles-frontend # 21.92% frontend cycles idle ( +- 0.10% )
2,800,298,015 stalled-cycles-backend # 6.16% backend cycles idle ( +- 0.32% )
79,241,190,850 instructions # 1.74 insn per cycle
# 0.13 stalled cycles per insn ( +- 0.00% )
17,616,096,146 branches # 1339.956 M/sec ( +- 0.00% )
176,106,232 branch-misses # 1.00% of all branches ( +- 0.18% )13.691078109 seconds time elapsed ( +- 0.03% )
^^^^^^^^^^^^AFTER
$ perf stat -r 10 taskset -c 3 ./proc-vmstatPerformance counter stats for 'taskset -c 3 ./proc-vmstat' (10 runs):
8688.353749 task-clock (msec) # 0.950 CPUs utilized ( +- 1.25% )
10 context-switches # 0.001 K/sec ( +- 2.13% )
1 cpu-migrations # 0.000 K/sec
104 page-faults # 0.012 K/sec ( +- 0.56% )
30,384,010,730 cycles # 3.497 GHz ( +- 0.07% )
12,296,259,407 stalled-cycles-frontend # 40.47% frontend cycles idle ( +- 0.13% )
3,370,668,651 stalled-cycles-backend # 11.09% backend cycles idle ( +- 0.69% )
28,969,052,879 instructions # 0.95 insn per cycle
# 0.42 stalled cycles per insn ( +- 0.01% )
6,308,245,891 branches # 726.058 M/sec ( +- 0.00% )
214,685,502 branch-misses # 3.40% of all branches ( +- 0.26% )9.146081052 seconds time elapsed ( +- 0.07% )
^^^^^^^^^^^vsnprintf() is slow because:
1. format_decode() is busy looking for format specifier: 2 branches
per character (not in this case, but in others)2. approximately million branches while parsing format mini language
and everywhere3. just look at what string() does /proc/vmstat is good case because
most of its content are stringsLink: http://lkml.kernel.org/r/20160806125455.GA1187@p183.telecom.by
Signed-off-by: Alexey Dobriyan
Cc: Joe Perches
Cc: Andi Kleen
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This came to light when implementing native 64-bit atomics for ARCv2.
The atomic64 self-test code uses CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
to check whether atomic64_dec_if_positive() is available. It seems it
was needed when not every arch defined it. However as of current code
the Kconfig option seems needless- for CONFIG_GENERIC_ATOMIC64 it is auto-enabled in lib/Kconfig and a
generic definition of API is present lib/atomic64.c
- arches with native 64-bit atomics select it in arch/*/Kconfig and
define the API in their headersSo I see no point in keeping the Kconfig option
Compile tested for:
- blackfin (CONFIG_GENERIC_ATOMIC64)
- x86 (!CONFIG_GENERIC_ATOMIC64)
- ia64Link: http://lkml.kernel.org/r/1473703083-8625-3-git-send-email-vgupta@synopsys.com
Signed-off-by: Vineet Gupta
Cc: Richard Henderson
Cc: Ivan Kokshaysky
Cc: Matt Turner
Cc: Russell King
Cc: Catalin Marinas
Cc: Will Deacon
Cc: Ralf Baechle
Cc: "James E.J. Bottomley"
Cc: Helge Deller
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: Michael Ellerman
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: "David S. Miller"
Cc: Chris Metcalf
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: "H. Peter Anvin"
Cc: Vineet Gupta
Cc: Zhaoxiu Zeng
Cc: Linus Walleij
Cc: Alexander Potapenko
Cc: Andrey Ryabinin
Cc: Herbert Xu
Cc: Ming Lin
Cc: Arnd Bergmann
Cc: Geert Uytterhoeven
Cc: Peter Zijlstra
Cc: Borislav Petkov
Cc: Andi Kleen
Cc: Boqun Feng
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This is based on s390 version and needed to get rid of
CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVELink: http://lkml.kernel.org/r/1473703083-8625-2-git-send-email-vgupta@synopsys.com
Signed-off-by: Vineet Gupta
Reported-by: kbuild test robot
Cc: Tony Luck
Cc: Fenghua Yu
Cc: Ingo Molnar
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The macro PAGE_ALIGNED() is prone to cause error because it doesn't
follow convention to parenthesize parameter @addr within macro body, for
example unsigned long *ptr = kmalloc(...); PAGE_ALIGNED(ptr + 16); for
the left parameter of macro IS_ALIGNED(), (unsigned long)(ptr + 16) is
desired but the actual one is (unsigned long)ptr + 16.It is fixed by simply canonicalizing macro PAGE_ALIGNED() definition.
Link: http://lkml.kernel.org/r/57EA6AE7.7090807@zoho.com
Signed-off-by: zijun_hu
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When the huge page is added to the page cahce (huge_add_to_page_cache),
the page private flag will be cleared. since this code
(remove_inode_hugepages) will only be called for pages in the page
cahce, PagePrivate(page) will always be false.The patch remove the code without any functional change.
Link: http://lkml.kernel.org/r/1475113323-29368-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang
Reviewed-by: Naoya Horiguchi
Reviewed-by: Mike Kravetz
Tested-by: Mike Kravetz
Acked-by: Michal Hocko
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently we do warn only about allocation failures but small
allocations are basically nofail and they might loop in the page
allocator for a long time. Especially when the reclaim cannot make any
progress - e.g. GFP_NOFS cannot invoke the oom killer and rely on a
different context to make a forward progress in case there is a lot
memory used by filesystems.Give us at least a clue when something like this happens and warn about
allocations which take more than 10s. Print the basic allocation
context information along with the cumulative time spent in the
allocation as well as the allocation stack. Repeat the warning after
every 10 seconds so that we know that the problem is permanent rather
than ephemeral.Link: http://lkml.kernel.org/r/20160929084407.7004-3-mhocko@kernel.org
Signed-off-by: Michal Hocko
Cc: Vlastimil Babka
Cc: Tetsuo Handa
Cc: Johannes Weiner
Cc: Mel Gorman
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
warn_alloc_failed is currently used from the page and vmalloc
allocators. This is a good reuse of the code except that vmalloc would
appreciate a slightly different warning message. This is already
handled by the fmt parameter except that"%s: page allocation failure: order:%u, mode:%#x(%pGg)"
is printed anyway. This might be quite misleading because it might be a
vmalloc failure which leads to the warning while the page allocator is
not the culprit here. Fix this by always using the fmt string and only
print the context that makes sense for the particular context (e.g.
order makes only very little sense for the vmalloc context).Rename the function to not miss any user and also because a later patch
will reuse it also for !failure cases.Link: http://lkml.kernel.org/r/20160929084407.7004-2-mhocko@kernel.org
Signed-off-by: Michal Hocko
Acked-by: Vlastimil Babka
Cc: Tetsuo Handa
Cc: Johannes Weiner
Cc: Mel Gorman
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We triggered a deadloop in truncate_inode_pages_range() on 32 bits
architecture with the test case bellow:...
fd = open();
write(fd, buf, 4096);
preadv64(fd, &iovec, 1, 0xffffffff000);
ftruncate(fd, 0);
...Then ftruncate() will not return forever.
The filesystem used in this case is ubifs, but it can be triggered on
many other filesystems.When preadv64() is called with offset=0xffffffff000, a page with
index=0xffffffff will be added to the radix tree of ->mapping. Then
this page can be found in ->mapping with pagevec_lookup(). After that,
truncate_inode_pages_range(), which is called in ftruncate(), will fall
into an infinite loop:- find a page with index=0xffffffff, since index>=end, this page won't
be truncated- index++, and index become 0
- the page with index=0xffffffff will be found again
The data type of index is unsigned long, so index won't overflow to 0 on
64 bits architecture in this case, and the dead loop won't happen.Since truncate_inode_pages_range() is executed with holding lock of
inode->i_rwsem, any operation related with this lock will be blocked,
and a hung task will happen, e.g.:INFO: task truncate_test:3364 blocked for more than 120 seconds.
...
call_rwsem_down_write_failed+0x17/0x30
generic_file_write_iter+0x32/0x1c0
ubifs_write_iter+0xcc/0x170
__vfs_write+0xc4/0x120
vfs_write+0xb2/0x1b0
SyS_write+0x46/0xa0The page with index=0xffffffff added to ->mapping is useless. Fix this
by checking the read position before allocating pages.Link: http://lkml.kernel.org/r/1475151010-40166-1-git-send-email-fangwei1@huawei.com
Signed-off-by: Wei Fang
Cc: Christoph Hellwig
Cc: Dave Chinner
Cc: Al Viro
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Arm64 supports gigantic pages after commit 084bd29810a5 ("ARM64: mm:
HugeTLB support.") however, it can only be allocated at boottime and
can't be freed.This patch selects ARCH_HAS_GIGANTIC_PAGE to make gigantic pages can be
allocated and freed at runtime for arch arm64.Link: http://lkml.kernel.org/r/1475227569-63446-3-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie
Acked-by: Michal Hocko
Acked-by: Catalin Marinas
Acked-by: Hillf Danton
Cc: Hanjun Guo
Cc: Will Deacon
Cc: Dave Hansen
Cc: Sudeep Holla
Cc: Mark Rutland
Cc: Rob Herring
Cc: Mike Kravetz
Cc: Naoya Horiguchi
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Avoid making ifdef get pretty unwieldy if many ARCHs support gigantic
page. No functional change with this patch.Link: http://lkml.kernel.org/r/1475227569-63446-2-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie
Suggested-by: Michal Hocko
Acked-by: Michal Hocko
Acked-by: Naoya Horiguchi
Acked-by: Hillf Danton
Cc: Hanjun Guo
Cc: Will Deacon
Cc: Dave Hansen
Cc: Sudeep Holla
Cc: Catalin Marinas
Cc: Mark Rutland
Cc: Rob Herring
Cc: Mike Kravetz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We have received a hard to explain oom report from a customer. The oom
triggered regardless there is a lot of free memory:PoolThread invoked oom-killer: gfp_mask=0x280da, order=0, oom_adj=0, oom_score_adj=0
PoolThread cpuset=/ mems_allowed=0-7
Pid: 30055, comm: PoolThread Tainted: G E X 3.0.101-80-default #1
Call Trace:
dump_trace+0x75/0x300
dump_stack+0x69/0x6f
dump_header+0x8e/0x110
oom_kill_process+0xa6/0x350
out_of_memory+0x2b7/0x310
__alloc_pages_slowpath+0x7dd/0x820
__alloc_pages_nodemask+0x1e9/0x200
alloc_pages_vma+0xe1/0x290
do_anonymous_page+0x13e/0x300
do_page_fault+0x1fd/0x4c0
page_fault+0x25/0x30
[...]
active_anon:1135959151 inactive_anon:1051962 isolated_anon:0
active_file:13093 inactive_file:222506 isolated_file:0
unevictable:262144 dirty:2 writeback:0 unstable:0
free:432672819 slab_reclaimable:7917 slab_unreclaimable:95308
mapped:261139 shmem:166297 pagetables:2228282 bounce:0
[...]
Node 0 DMA free:15896kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15672kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 2892 775542 775542
Node 0 DMA32 free:2783784kB min:28kB low:32kB high:40kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:2961572kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
lowmem_reserve[]: 0 0 772650 772650
Node 0 Normal free:8120kB min:8160kB low:10200kB high:12240kB active_anon:779334960kB inactive_anon:2198744kB active_file:0kB inactive_file:180kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:791193600kB mlocked:131072kB dirty:0kB writeback:0kB mapped:372940kB shmem:361480kB slab_reclaimable:4536kB slab_unreclaimable:68472kB kernel_stack:10104kB pagetables:1414820kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:2280 all_unreclaimable? yes
lowmem_reserve[]: 0 0 0 0
Node 1 Normal free:476718144kB min:8192kB low:10240kB high:12288kB active_anon:307623696kB inactive_anon:283620kB active_file:10392kB inactive_file:69908kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:4kB writeback:0kB mapped:257208kB shmem:189896kB slab_reclaimable:3868kB slab_unreclaimable:44756kB kernel_stack:1848kB pagetables:1369432kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 2 Normal free:386002452kB min:8192kB low:10240kB high:12288kB active_anon:398563752kB inactive_anon:68184kB active_file:10292kB inactive_file:29936kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:32084kB shmem:776kB slab_reclaimable:6888kB slab_unreclaimable:60056kB kernel_stack:8208kB pagetables:1282880kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 3 Normal free:196406760kB min:8192kB low:10240kB high:12288kB active_anon:587445640kB inactive_anon:164396kB active_file:5716kB inactive_file:709844kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:291776kB shmem:111416kB slab_reclaimable:5152kB slab_unreclaimable:44516kB kernel_stack:2168kB pagetables:1455956kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 4 Normal free:425338880kB min:8192kB low:10240kB high:12288kB active_anon:359695204kB inactive_anon:43216kB active_file:5748kB inactive_file:14772kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:24708kB shmem:1120kB slab_reclaimable:1884kB slab_unreclaimable:41060kB kernel_stack:1856kB pagetables:1100208kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 5 Normal free:11140kB min:8192kB low:10240kB high:12288kB active_anon:784240872kB inactive_anon:1217164kB active_file:28kB inactive_file:48kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:11408kB shmem:0kB slab_reclaimable:2008kB slab_unreclaimable:49220kB kernel_stack:1360kB pagetables:531600kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:1202 all_unreclaimable? yes
lowmem_reserve[]: 0 0 0 0
Node 6 Normal free:243395332kB min:8192kB low:10240kB high:12288kB active_anon:542015544kB inactive_anon:40208kB active_file:968kB inactive_file:8484kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:0kB writeback:0kB mapped:19992kB shmem:496kB slab_reclaimable:1672kB slab_unreclaimable:37052kB kernel_stack:2088kB pagetables:750264kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0
Node 7 Normal free:10768kB min:8192kB low:10240kB high:12288kB active_anon:784916936kB inactive_anon:192316kB active_file:19228kB inactive_file:56852kB unevictable:131072kB isolated(anon):0kB isolated(file):0kB present:794296320kB mlocked:131072kB dirty:4kB writeback:0kB mapped:34440kB shmem:4kB slab_reclaimable:5660kB slab_unreclaimable:36100kB kernel_stack:1328kB pagetables:1007968kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
lowmem_reserve[]: 0 0 0 0So all nodes but Node 0 have a lot of free memory which should suggest
that there is an available memory especially when mems_allowed=0-7. One
could speculate that a massive process has managed to terminate and free
up a lot of memory while racing with the above allocation request.
Although this is highly unlikely it cannot be ruled out.A further debugging, however shown that the faulting process had
mempolicy (not cpuset) to bind to Node 0. We cannot see that
information from the report though. mems_allowed turned out to be more
confusing than really helpful.Fix this by always priting the nodemask. It is either mempolicy mask
(and non-null) or the one defined by the cpusets. The new output for
the above oom report would bePoolThread invoked oom-killer: gfp_mask=0x280da(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=0, order=0, oom_adj=0, oom_score_adj=0
This patch doesn't touch show_mem and the node filtering based on the
cpuset node mask because mempolicy is always a subset of cpusets and
seeing the full cpuset oom context might be helpful for tunning more
specific mempolicies inside cpusets (e.g. when they turn out to be too
restrictive). To prevent from ugly ifdefs the mask is printed even for
!NUMA configurations but this should be OK (a single node will be
printed).Link: http://lkml.kernel.org/r/20160930214146.28600-1-mhocko@kernel.org
Signed-off-by: Michal Hocko
Reported-by: Sellami Abdelkader
Acked-by: Vlastimil Babka
Cc: David Rientjes
Cc: Sellami Abdelkader
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Let's add comment on why we skip page_mapcount() for sl[aou]b pages.
Link: http://lkml.kernel.org/r/20160922105532.GB24593@node
Signed-off-by: Kirill A. Shutemov
Acked-by: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The old code was always doing:
vma->vm_end = next->vm_end
vma_rb_erase(next) // in __vma_unlink
vma->vm_next = next->vm_next // in __vma_unlink
next = vma->vm_next
vma_gap_update(next)The new code still does the above for remove_next == 1 and 2, but for
remove_next == 3 it has been changed and it does:next->vm_start = vma->vm_start
vma_rb_erase(vma) // in __vma_unlink
vma_gap_update(next)In the latter case, while unlinking "vma", validate_mm_rb() is told to
ignore "vma" that is being removed, but next->vm_start was reduced
instead. So for the new case, to avoid the false positive from
validate_mm_rb, it should be "next" that is ignored when "vma" is
being unlinked."vma" and "next" in the above comment, considered pre-swap().
Link: http://lkml.kernel.org/r/1474492522-2261-4-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Tested-by: Shaun Tancheff
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The cases are three not two.
Link: http://lkml.kernel.org/r/1474492522-2261-3-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
If next would be NULL we couldn't reach such code path.
Link: http://lkml.kernel.org/r/1474309513-20313-2-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The rmap_walk can access vm_page_prot (and potentially vm_flags in the
pte/pmd manipulations). So it's not safe to wait the caller to update
the vm_page_prot/vm_flags after vma_merge returned potentially removing
the "next" vma and extending the "current" vma over the
next->vm_start,vm_end range, but still with the "current" vma
vm_page_prot, after releasing the rmap locks.The vm_page_prot/vm_flags must be transferred from the "next" vma to the
current vma while vma_merge still holds the rmap locks.The side effect of this race condition is pte corruption during migrate
as remove_migration_ptes when run on a address of the "next" vma that
got removed, used the vm_page_prot of the current vma.migrate mprotect
------------ -------------
migrating in "next" vma
vma_merge() # removes "next" vma and
# extends "current" vma
# current vma is not with
# vm_page_prot updated
remove_migration_ptes
read vm_page_prot of current "vma"
establish pte with wrong permissions
vm_set_page_prot(vma) # too late!
change_protection in the old vma range
only, next range is not updatedThis caused segmentation faults and potentially memory corruption in
heavy mprotect loads with some light page migration caused by compaction
in the background.Hugh Dickins pointed out the comment about the Odd case 8 in vma_merge
which confirms the case 8 is only buggy one where the race can trigger,
in all other vma_merge cases the above cannot happen.This fix removes the oddness factor from case 8 and it converts it from:
AAAA
PPPPNNNNXXXX -> PPPPNNNNNNNNto:
AAAA
PPPPNNNNXXXX -> PPPPXXXXXXXXXXXX has the right vma properties for the whole merged vma returned by
vma_adjust, so it solves the problem fully. It has the added benefits
that the callers could stop updating vma properties when vma_merge
succeeds however the callers are not updated by this patch (there are
bits like VM_SOFTDIRTY that still need special care for the whole range,
as the vma merging ignores them, but as long as they're not processed by
rmap walks and instead they're accessed with the mmap_sem at least for
reading, they are fine not to be updated within vma_adjust before
releasing the rmap_locks).Link: http://lkml.kernel.org/r/1474309513-20313-1-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Reported-by: Aditya Mandaleeka
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
mm->highest_vm_end doesn't need any update.
After finally removing the oddness from vma_merge case 8 that was
causing:1) constant risk of trouble whenever anybody would check vma fields
from rmap_walks, like it happened when page migration was
introduced and it read the vma->vm_page_prot from a rmap_walk2) the callers of vma_merge to re-initialize any value different from
the current vma, instead of vma_merge() more reliably returning a
vma that already matches all fields passed as parameter.. it is also worth to take the opportunity of cleaning up superfluous
code in vma_adjust(), that if not removed adds up to the hard
readability of the function.Link: http://lkml.kernel.org/r/1474492522-2261-5-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
vma->vm_page_prot is read lockless from the rmap_walk, it may be updated
concurrently and this prevents the risk of reading intermediate values.Link: http://lkml.kernel.org/r/1474660305-19222-1-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli
Cc: Rik van Riel
Cc: Hugh Dickins
Cc: Mel Gorman
Cc: Jan Vorlicek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
According to Hugh's suggestion, alloc_stable_node() with GFP_KERNEL can
in rare cases cause a hung task warning.At present, if alloc_stable_node() allocation fails, two break_cows may
want to allocate a couple of pages, and the issue will come up when free
memory is under pressure.We fix it by adding __GFP_HIGH to GFP, to grant access to memory
reserves, increasing the likelihood of allocation success.[akpm@linux-foundation.org: tweak comment]
Link: http://lkml.kernel.org/r/1474354484-58233-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang
Suggested-by: Hugh Dickins
Acked-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fix typo in comment.
Link: http://lkml.kernel.org/r/1474788764-5774-1-git-send-email-ysxie@foxmail.com
Signed-off-by: Yisheng Xie
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
For every pfn aligned to minimum_order, dissolve_free_huge_pages() will
call dissolve_free_huge_page() which takes the hugetlb spinlock, even if
the page is not huge at all or a hugepage that is in-use.Improve this by doing the PageHuge() and page_count() checks already in
dissolve_free_huge_pages() before calling dissolve_free_huge_page(). In
dissolve_free_huge_page(), when holding the spinlock, those checks need
to be revalidated.Link: http://lkml.kernel.org/r/20160926172811.94033-4-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer
Acked-by: Michal Hocko
Acked-by: Naoya Horiguchi
Cc: "Kirill A . Shutemov"
Cc: Vlastimil Babka
Cc: Mike Kravetz
Cc: "Aneesh Kumar K . V"
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Rui Teng
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
In dissolve_free_huge_pages(), free hugepages will be dissolved without
making sure that there are enough of them left to satisfy hugepage
reservations.Fix this by adding a return value to dissolve_free_huge_pages() and
checking h->free_huge_pages vs. h->resv_huge_pages. Note that this may
lead to the situation where dissolve_free_huge_page() returns an error
and all free hugepages that were dissolved before that error are lost,
while the memory block still cannot be set offline.Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Link: http://lkml.kernel.org/r/20160926172811.94033-3-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer
Acked-by: Michal Hocko
Acked-by: Naoya Horiguchi
Cc: "Kirill A . Shutemov"
Cc: Vlastimil Babka
Cc: Mike Kravetz
Cc: "Aneesh Kumar K . V"
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Rui Teng
Cc: Dave Hansen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "mm/hugetlb: memory offline issues with hugepages", v4.
This addresses several issues with hugepages and memory offline. While
the first patch fixes a panic, and is therefore rather important, the
last patch is just a performance optimization.The second patch fixes a theoretical issue with reserved hugepages,
while still leaving some ugly usability issue, see description.This patch (of 3):
dissolve_free_huge_pages() will either run into the VM_BUG_ON() or a
list corruption and addressing exception when trying to set a memory
block offline that is part (but not the first part) of a "gigantic"
hugetlb page with a size > memory block size.When no other smaller hugetlb page sizes are present, the VM_BUG_ON()
will trigger directly. In the other case we will run into an addressing
exception later, because dissolve_free_huge_page() will not work on the
head page of the compound hugetlb page which will result in a NULL
hstate from page_hstate().To fix this, first remove the VM_BUG_ON() because it is wrong, and then
use the compound head page in dissolve_free_huge_page(). This means
that an unused pre-allocated gigantic page that has any part of itself
inside the memory block that is going offline will be dissolved
completely. Losing an unused gigantic hugepage is preferable to failing
the memory offline, for example in the situation where a (possibly
faulty) memory DIMM needs to go offline.Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Link: http://lkml.kernel.org/r/20160926172811.94033-2-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer
Acked-by: Michal Hocko
Acked-by: Naoya Horiguchi
Cc: "Kirill A . Shutemov"
Cc: Vlastimil Babka
Cc: Mike Kravetz
Cc: "Aneesh Kumar K . V"
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Rui Teng
Cc: Dave Hansen
Cc:
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Commit b4def3509d18 ("mm, nobootmem: clean-up of free_low_memory_core_early()")
removed the unnecessary nodeid argument, after that, this comment
becomes more confused. We should move it to the right place.Fixes: b4def3509d18c1db9 ("mm, nobootmem: clean-up of free_low_memory_core_early()")
Link: http://lkml.kernel.org/r/1473996082-14603-1-git-send-email-wanlong.gao@gmail.com
Signed-off-by: Wanlong Gao
Cc: Joonsoo Kim
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
