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Commit Graph

2739 Commits

Author SHA1 Message Date
Carlos Eduardo Seo
9aea0e89b6 runtime: make sure R0 is zero before _main on ppc64le
_main has an early check to verify if a binary is statically or dynamically
linked that depends on R0 being zero. R0 is not guaranteed to be zero at that
point and this was breaking Go on Alpine for ppc64le.

Change-Id: I4a1059ff7fd3db6fc489e7dcfe631c1814dd965b
Reviewed-on: https://go-review.googlesource.com/54730
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
2017-08-11 17:46:24 +00:00
Hiroshi Ioka
e9348ab4e9 runtime: move mincore from stubs.go to os_linux.go
Although mincore is declared in stubs.go, mincore isn't used by any
OSes except linux. Move it to os_linux.go and clean up unused code.

Change-Id: I6cfb0fed85c0317a4d091a2722ac55fa79fc7c9a
Reviewed-on: https://go-review.googlesource.com/54910
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-11 05:08:44 +00:00
Hiroshi Ioka
6bf2208032 runtime/cgo: update comments
Change-Id: Ib5356181c3204c8f9922eeb4da1c06bfdb18f443
Reviewed-on: https://go-review.googlesource.com/54812
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-11 04:55:42 +00:00
Austin Clements
a6ae01a64a runtime: add "max waste" column to size class table comment
This computes the maximum possible waste in a size class due to both
internal and external fragmentation as a percent of the span size.
This parallels the reasoning about overhead in the comment at the top
of mksizeclasses.go and confirms that comment's assertion that (except
for the few smallest size classes), none of the size classes have
worst-case internal and external fragmentation simultaneously.

Change-Id: Idb66fe6c241d56f33d391831d4cd5a626955562b
Reviewed-on: https://go-review.googlesource.com/49370
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-08-10 21:45:01 +00:00
Elias Naur
5500c9ce27 runtime: when dying from a signal use the previous signal handler
Before this CL, whenever the Go runtime wanted to kill its own
process with a signal dieFromSignal would reset the signal handler
to _SIG_DFL.

Unfortunately, if any signal handler were installed before the Go
runtime initialized, it wouldn't be invoked either.

Instead, use whatever signal handler was installed before
initialization.

The motivating use case is Crashlytics on Android. Before this CL,
Crashlytics would not consider a crash from a panic() since the
corresponding SIGABRT never reached its signal handler.

Updates #11382
Updates #20392 (perhaps even fixes it)
Fixes #19389

Change-Id: I0c8633329433b45cbb3b16571bea227e38e8be2e
Reviewed-on: https://go-review.googlesource.com/49590
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-10 10:08:17 +00:00
Elias Naur
7d80a2ea18 runtime: allow crash() to raise SIGABRT on darwin/arm64
To avoid gigantic core dumps, the runtime avoids raising SIGABRT
on crashes on 64-bit Darwin systems. Mobile OS'es (probably) don't
generate huge core dumps, so to aid crash reporters, allow SIGABRT
on crashes on darwin/arm64.

Change-Id: I4a29608f400967d76f9bd0643fea22244c2da9df
Reviewed-on: https://go-review.googlesource.com/49770
Run-TryBot: Elias Naur <elias.naur@gmail.com>
Reviewed-by: Avelino <t@avelino.xxx>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-10 10:07:36 +00:00
Lynn Boger
3e7abf82e3 cmd/go,cmd/link: support buildmode c-shared on ppc64le
This change enables buildmode c-shared on ppc64le.

A bug was fixed in runtime/rt0_linux_ppc64le.s that was necessary to
make this work.  In _rt0_ppc64le_linux_lib, there is code to store
the value of r2 onto the caller's stack.  However, if this file
is compiled using a build mode that maintains the TOC address in
r2, then instructions will be inserted at the beginning of this
function to generate the r2 value for the callee, not the caller.
That means the r2 value for the callee is stored onto the caller's
stack.  If caller and callee don't have the same r2 values, then
the caller will restore the wrong r2 value after it returns.  This
situation can happen when using dlopen since the caller of this
function will be in ld64.so and will definitely have a different
TOC.

Updates #20756

Change-Id: I6e165e0d0716e73721bbbcc520e8302e4856e3ba
Reviewed-on: https://go-review.googlesource.com/53890
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-09 17:11:38 +00:00
Austin Clements
53f2d53450 runtime: document concurrency of mheap.spans
We use lock-free reads from mheap.spans, but the safety of these is
somewhat subtle. Document this.

Change-Id: I928c893232176135308e38bed788d5f84ff11533
Reviewed-on: https://go-review.googlesource.com/54310
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-08-09 16:06:23 +00:00
Josh Bleecher Snyder
64bd2c49b4 runtime: simplify b.tophash[i] calculation
The compiler is now smart enough not to insert a bounds check.
Not only is this simpler, it eliminates a LEAQ from the
generated code.

Change-Id: Ie90cbd11584542edd99edd5456d9b02c406e8063
Reviewed-on: https://go-review.googlesource.com/53892
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-08-08 19:51:48 +00:00
Josh Bleecher Snyder
dabc361847 runtime: use constants for map string key size
It appears that this was just missed
by accident in the original implementation.

Change-Id: Id87147bcb7a685d624eac7034342a305ad644e7a
Reviewed-on: https://go-review.googlesource.com/53891
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Avelino <t@avelino.xxx>
2017-08-08 19:50:13 +00:00
Martin Möhrmann
e0e7c03d14 runtime, internal/cpu: change cache line size for arm64 to 64 bytes
According to http://infocenter.arm.com:
* ARM Cortex-A53 (Raspberry Pi 3, Pine A64)
* ARM Cortex-A57 (Opteron A1100, Tegra X1)
* ARM Cortex-A72
all have a cache line size of 64 bytes.

Change-Id: I4b333e930792fb1a221b3ca6f395bfa1b7762afa
Reviewed-on: https://go-review.googlesource.com/43250
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-08-08 06:49:49 +00:00
Martin Möhrmann
7045e6f6c4 runtime: remove unused prefetch functions
The only non test user of the assembler prefetch functions is the
heapBits.prefetch function which is itself unused.

The runtime prefetch functions have no functionality on most platforms
and are not inlineable since they are written in assembler. The function
call overhead eliminates the performance gains that could be achieved with
prefetching and would degrade performance for platforms where the functions
are no-ops.

If prefetch functions are needed back again later they can be improved
by avoiding the function call overhead and implementing them as intrinsics.

Change-Id: I52c553cf3607ffe09f0441c6e7a0a818cb21117d
Reviewed-on: https://go-review.googlesource.com/44370
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-08-08 06:43:49 +00:00
Keith Randall
579120323f runtime: mapassign_* should use typedmemmove to update keys
We need to make sure that when the key contains a pointer, we use
a write barrier to update the key.

Also mapdelete_* should use typedmemclr.

Fixes #21297

Change-Id: I63dc90bec1cb909c2c6e08676c9ec853d736cdf8
Reviewed-on: https://go-review.googlesource.com/53414
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-08-07 06:24:42 +00:00
Ian Lance Taylor
f096b5b340 runtime: mark activeModules nosplit/nowritebarrier
The activeModules function is called by the cgo pointer checking code,
which is called by the write barrier (when GODEBUG=cgocheck=2), and as
such must be nosplit/nowritebarrier.

Fixes #21306

Change-Id: I57f2124f14de7f3872b2de9532abab15df95d45a
Reviewed-on: https://go-review.googlesource.com/53352
Reviewed-by: Austin Clements <austin@google.com>
2017-08-05 18:05:41 +00:00
Austin Clements
623e2c4603 runtime: map bitmap and spans during heap initialization
We lazily map the bitmap and spans areas as the heap grows. However,
right now we're very slightly too lazy. Specifically, the following
can happen on 32-bit:

1. mallocinit fails to allocate any heap arena, so
   arena_used == arena_alloc == arena_end == bitmap.

2. There's less than 256MB between the end of the bitmap mapping and
   the next mapping.

3. On the first allocation, mheap.sysAlloc sees that there's not
   enough room in [arena_alloc, arena_end) because there's no room at
   all. It gets a 256MB mapping from somewhere *lower* in the address
   space than arena_used and sets arena_alloc and arena_end to this
   hole.

4. Since the new arena_alloc is lower than arena_used, mheap.sysAlloc
   doesn't bother to call mheap.setArenaUsed, so we still don't have a
   bitmap mapping or a spans array mapping.

5. mheap.grow, which called mheap.sysAlloc, attempts to fill in the
   spans array and crashes.

Fix this by mapping the metadata regions for the initial arena_used
when the heap is initialized, rather than trying to wait for an
allocation. This maintains the intended invariant that the structures
are always mapped for [arena_start, arena_used).

Fixes #21044.

Change-Id: I4422375a6e234b9f979d22135fc63ae3395946b0
Reviewed-on: https://go-review.googlesource.com/51714
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-07-31 16:52:36 +00:00
Austin Clements
780249eed4 runtime: fall back to small mmaps if we fail to grow reservation
Right now, if it's possible to grow the arena reservation but
mheap.sysAlloc fails to get 256MB more of memory, it simply fails.
However, on 32-bit we have a fallback path that uses much smaller
mmaps that could take in this situation, but fail to.

This commit fixes mheap.sysAlloc to use a common failure path in case
it can't grow the reservation. On 32-bit, this path includes the
fallback.

Ideally, mheap.sysAlloc would attempt smaller reservation growths
first, but taking the fallback path is a simple change for Go 1.9.

Updates #21044 (fixes one of two issues).

Change-Id: I1e0035ffba986c3551479d5742809e43da5e7c73
Reviewed-on: https://go-review.googlesource.com/51713
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-07-31 14:05:58 +00:00
Vladimir Stefanovic
835dfef939 runtime/pprof: prevent a deadlock that SIGPROF might create on mips{,le}
64bit atomics on mips/mipsle are implemented using spinlocks. If SIGPROF
is received while the program is in the critical section, it will try to
write the sample using the same spinlock, creating a deadloop.
Prevent it by creating a counter of SIGPROFs during atomic64 and
postpone writing the sample(s) until called from elsewhere, with
pc set to _LostSIGPROFDuringAtomic64.

Added a test case, per Cherry's suggestion. Works around #20146.

Change-Id: Icff504180bae4ee83d78b19c0d9d6a80097087f9
Reviewed-on: https://go-review.googlesource.com/42652
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-07-26 13:29:59 +00:00
Austin Clements
fa3c5173a5 runtime: improve out-of-memory message when VirtualAlloc fails
Fixes #19514.

Change-Id: I93600d5c3d11ecab5a47dd4cd55ed3aea05e221e
Reviewed-on: https://go-review.googlesource.com/49611
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-21 01:00:33 +00:00
Austin Clements
37b7880d15 runtime: use SIGKILL if SIGQUIT is blocked; skip tests that need SIGQUIT
The runtime tests may be invoked from a parent that has SIGQUIT
blocked. For example, Java invokes subprocesses this way. In this
situation, TestCrashDumpsAllThreads and TestPanicSystemstack will fail
because they depend on SIGQUIT to get tracebacks, and any subprocess
test that times out will fail to kill the subprocess.

Fix this by detecting if SIGQUIT is blocked and, if so, skipping tests
that depend on it and using SIGKILL to kill timed-out subprocesses.

Based on a fix by Carl Henrik Lunde in
https://golang.org/issue/19196#issuecomment-316145733

Fixes #19196.

Change-Id: Ia20bf15b96086487d0ef6b75239dcc260c21714c
Reviewed-on: https://go-review.googlesource.com/50330
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-07-20 18:09:18 +00:00
Ian Lance Taylor
28f650a2f7 runtime: don't call libc sigaction function in forked child
If we are using vfork, and if something (such as TSAN) is intercepting
the sigaction function, then we must call the system call, not the
libc function. Otherwise the intercepted sigaction call in the child
may trash the data structures in the parent.

Change-Id: Id9588bfeaa934f32c920bf829c5839be5cacf243
Reviewed-on: https://go-review.googlesource.com/50251
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
2017-07-20 18:02:47 +00:00
Austin Clements
ffd5687a82 runtime: only trace mark assists that do work
Currently we trace mark assists even if they're satisfied entirely by
stealing. This means even if background marking is keeping up with
allocation, we'll still emit a trace event every N bytes of
allocation. The event will be a few microseconds, if that, but they're
frequent enough that, when zoomed out in the trace view, it looks like
all of the time is spent in mark assists even if almost none is.

Change this so we only emit a trace event if the assist actually has
to do assisting. This makes the traces of these events far more
useful.

Change-Id: If4aed1c413b814341ef2fba61d2f10751d00451b
Reviewed-on: https://go-review.googlesource.com/50030
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-07-19 20:56:20 +00:00
Austin Clements
73d0273573 runtime: move tSweepTerm capture closer to STW
tSweepTerm and pauseStart are supposed to be when STW was triggered,
but right now they're captured a bit before STW. Move these down to
immediately before we trigger STW.

Fixes #19590.

Change-Id: Icd48a5c4d45c9b36187ff986e4f178b5064556c1
Reviewed-on: https://go-review.googlesource.com/49612
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-18 16:13:05 +00:00
Austin Clements
c2c07c7989 runtime: always use 2MB stacks on 64-bit Windows
Currently, Windows stacks are either 128kB or 2MB depending on whether
the binary uses cgo. This is because we assume that Go system stacks
and the small amount of C code invoked by the standard library can
operate within smaller stacks, but general Windows C code assumes
larger stacks.

However, it's easy to call into arbitrary C code using the syscall
package on Windows without ever importing cgo into a binary. Such
binaries need larger system stacks even though they don't use cgo.

Fix this on 64-bit by increasing the system stack size to 2MB always.
This only costs address space, which is free enough on 64-bit to not
worry about. We keep (for now) the existing heuristic on 32-bit, where
address space comes at more of a premium.

Updates #20975.

Change-Id: Iaaaa9a2fcbadc825cddc797aaaea8d34ef8debf2
Reviewed-on: https://go-review.googlesource.com/49331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
2017-07-18 14:35:35 +00:00
Daniel Morsing
f062955ea7 runtime: fix duplicate "the"s
kicking off contributing again with a classic

Change-Id: Ifb0aed8f1dc854f85751ce0495967a3c4315128d
Reviewed-on: https://go-review.googlesource.com/49016
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-15 21:12:56 +00:00
Ian Lance Taylor
7e172509d9 runtime: don't call t.Parallel in TestCgoSignalDeadlock
It seems that when too much other code is running on the system,
the testprogcgo code can overrun its timeouts.

Updates #18598.

Not marking the issue as fixed until it doesn't recur for some time.

Change-Id: Ieaf106b41986fdda76b1d027bb9d5e3fb805cc3b
Reviewed-on: https://go-review.googlesource.com/48233
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-07-13 04:07:39 +00:00
Austin Clements
2673f9ed23 runtime: pass CLONE_SYSVSEM to clone
SysV semaphore undo lists should be shared by threads, just like
several other resources listed in cloneFlags. Currently we don't do
this, but it probably doesn't affect anything because 1) probably
nobody uses SysV semaphores from Go and 2) Go-created threads never
exit until the process does. Beyond being the right thing to do,
user-level QEMU requires this flag because it depends on glibc to
create new threads and glibc uses this flag.

Fixes #20763.

Change-Id: I1d1dafec53ed87e0f4d4d432b945e8e68bb72dcd
Reviewed-on: https://go-review.googlesource.com/48170
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-12 17:42:50 +00:00
Austin Clements
286599f270 runtime: make TestStackGrowth a serial test
TestStackGrowth is currently a parallel test. However, it depends on a
20 second timeout, which is already dubious in a parallel test, and
became really problematic on slow builders when runtime.GC switched to
triggering concurrent GC instead of STW GC. Before that change, the
test spent much of its time in STW GC, so it wasn't *really* parallel.
After that change, it was competing with all of the other parallel
tests and GC likely started taking ~4 times longer. On most builders
the whole test runs in well under a second, but on the slow builders
that was enough to push it over the 20 second timeout.

Fix this by making the test serial.

Updates #19381 (probably fixes it, but we'll have to wait and see).

Change-Id: I21af7cf543ab07f1ec1c930bfcb355b0df75672d
Reviewed-on: https://go-review.googlesource.com/48110
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Elias Naur <elias.naur@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-11 18:32:56 +00:00
Costin Chirvasuta
58ae050055 runtime: simplify description of FuncForPC behavior in case of inlining
The current description refers to the outermost "frame" which can be
misleading. A user reading it can think it means a stack frame.

Change-Id: Ie2c7cb4b4db8f41572df206478ce3b46a0245a5d
Reviewed-on: https://go-review.googlesource.com/47850
Reviewed-by: Austin Clements <austin@google.com>
2017-07-11 14:01:04 +00:00
Austin Clements
093adeef40 runtime: use next timer to decide whether to relax
Currently, sysmon waits 60 ms during idle before relaxing. This is
primarily to avoid reducing the precision of short-duration timers. Of
course, if there are no short-duration timers, this wastes 60 ms
running the timer at high resolution.

Improve this by instead inspecting the time until the next timer fires
and relaxing the timer resolution immediately if the next timer won't
fire for a while.

Updates #20937.

Change-Id: If4ad0a565b65a9b3e8c4cdc2eff1486968c79f24
Reviewed-on: https://go-review.googlesource.com/47833
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-07 21:22:31 +00:00
Austin Clements
7a8f39fa14 runtime: delay before osRelaxing
Currently, sysmon relaxes the Windows timer resolution as soon as the
Go process becomes idle. However, if it's going idle because of a
short sleep (< 15.6 ms), this can turn that short sleep into a long
sleep (15.6 ms).

To address this, wait for 60 ms of idleness before relaxing the timer
resolution. It would be better to check the time until the next wakeup
and relax immediately if it makes sense, but there's currently no
interaction between sysmon and the timer subsystem, so adding this
simple delay is a much simpler and safer change for late in the
release cycle.

Fixes #20937.

Change-Id: I817db24c3bdfa06dba04b7bc197cfd554363c379
Reviewed-on: https://go-review.googlesource.com/47832
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-07 21:02:40 +00:00
Austin Clements
87a51a0787 runtime: save r11 in ARM addmoduledata
R11 is callee-save in the C ABI, but the temporary register in the Go
ABI. Currently it's being clobbered by runtime.addmoduledata, which
has to follow the C ABI. The observed effect of this was that
dl_open_worker was returning to a bad PC because after it failed to
restore its SP because it was using R11 as a frame pointer.

Fix this by saving R11 around addmoduledata.

Fixes #19674.

Change-Id: Iaacbcc76809a3aa536e9897770831dcbcb6c8245
Reviewed-on: https://go-review.googlesource.com/47831
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-07-07 20:24:36 +00:00
Austin Clements
d58125ecd2 runtime: document FuncForPC behavior with inlining
Change-Id: I1c02aa4f7131ae984fda66b32e8a993c0a40b8f4
Reviewed-on: https://go-review.googlesource.com/47690
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2017-07-07 19:30:06 +00:00
Austin Clements
f3b5a2bc19 runtime: prevent descheduling while holding rwmutex read lock
Currently only the rwmutex write lock prevents descheduling. The read
lock does not. This leads to the following situation:

1. A reader acquires the lock and gets descheduled.

2. GOMAXPROCS writers attempt to acquire the lock (or at least one
writer does, followed by readers). This blocks all of the Ps.

3. There is no 3. The descheduled reader never gets to run again
because there are no Ps, so it never releases the lock and the system
deadlocks.

Fix this by preventing descheduling while holding the read lock. This
requires also rewriting TestParallelRWMutexReaders to always create
enough GOMAXPROCS and to use non-blocking operations for
synchronization.

Fixes #20903.

Change-Id: Ibd460663a7e5a555be5490e13b2eaaa295fac39f
Reviewed-on: https://go-review.googlesource.com/47632
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-07-06 17:04:25 +00:00
Fabian Wickborn
b5240daa2f runtime/pprof: Fix type name in function comment
The name LabelList was changed to LabelSet during the development of the
proposal [1], except in one function comment. This commit fixes that.

Fixes #20905.

[1] https://github.com/golang/go/issues/17280

Change-Id: Id4f48d59d7d513fa24b2e42795c2baa5ceb78f36
Reviewed-on: https://go-review.googlesource.com/47470
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-07-05 18:26:47 +00:00
Austin Clements
a89e6be5e4 runtime: clean up mheap.allocLarge
mheap.allocLarge just calls bestFitTreap and is the only caller of
bestFitTreap. Flatten these into a single function. Also fix their
comments: allocLarge claims to return exactly npages but can in fact
return a larger span, and h.freelarge is not in fact indexed by span
start address.

Change-Id: Ia20112bdc46643a501ea82ea77c58596bc96f125
Reviewed-on: https://go-review.googlesource.com/47315
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-07-03 14:08:01 +00:00
Joe Tsai
a776087ee3 runtime: allow calling Func.Name on nil pointer
The Func type has allowed calling the Func.Name method on a nil pointer
since Go1.2, where it returned an empty string. A regression caused by
CL/37331 caused this behavior to change. This breaks code that lazily
does runtime.FuncForPC(myPtr).Name() without first checking that myPtr
is actually non-nil.

Fixes #20872

Change-Id: Iae9a2ebabca5e9d1f5a2cdaf2f30e9c6198fec4f
Reviewed-on: https://go-review.googlesource.com/47354
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-06-30 23:42:03 +00:00
Austin Clements
9745e88b22 runtime: use rwmutex for execLock
Currently the execLock is a mutex, which has the unfortunate
side-effect of serializing all thread creation. This replaces it with
an rwmutex so threads can be created in parallel, but exec still
blocks thread creation.

Fixes #20738.

Change-Id: Ia8f30a92053c3d28af460b0da71176abe5fd074b
Reviewed-on: https://go-review.googlesource.com/47072
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-28 22:08:59 +00:00
Austin Clements
80832974ac runtime: make rwmutex work on Ms instead of Gs
Currently runtime.rwmutex is written to block the calling goroutine
rather than the calling thread. However, rwmutex was intended to be
used in the scheduler, which means it needs to be a thread-level
synchronization primitive.

Hence, this modifies rwmutex to synchronize threads instead of
goroutines. This has the consequence of making it write-barrier-free,
which is also important for using it in the scheduler.

The implementation makes three changes: it replaces the "w" semaphore
with a mutex, since this was all it was being used for anyway; it
replaces "writerSem" with a single pending M that parks on its note;
and it replaces "readerSem" with a list of Ms that park on their notes
plus a pass count that together emulate a counting semaphore. I
model-checked the safety and liveness of this implementation through
>1 billion schedules.

For #20738.

Change-Id: I3cf5a18c266a96a3f38165083812803510217787
Reviewed-on: https://go-review.googlesource.com/47071
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-28 22:08:57 +00:00
Shawn Walker-Salas
e7823d656e runtime: temporarily skip gdb python-related tests on solaris
Updates #20821

Change-Id: I77a5b9a3bbb931845ef52a479549d71069af9540
Reviewed-on: https://go-review.googlesource.com/46913
Run-TryBot: Shawn Walker-Salas <shawn.walker@oracle.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-06-28 05:01:20 +00:00
Ian Lance Taylor
93870aeee9 runtime: get more info for TestCgoSignalDeadlock failures
Updates #18598

Change-Id: I13c60124714cf9d1537efa0a7dd1e6a0fed9ae5b
Reviewed-on: https://go-review.googlesource.com/46723
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-06-27 00:34:53 +00:00
Austin Clements
489620d878 runtime: drain local runq when dedicated mark worker runs
When the dedicated mark worker runs, the scheduler won't run on that P
again until GC runs out of mark work. As a result, any goroutines in
that P's local run queue are stranded until another P steals them. In
a normally operating system this may take a long time, and in a 100%
busy system, the scheduler never attempts to steal from another P.

Fix this by draining the local run queue into the global run queue if
the dedicated mark worker has run for long enough. We don't do this
immediately upon scheduling the dedicated mark worker in order to
avoid destroying locality if the mark worker runs for a short time.
Instead, the scheduler delays draining the run queue until the mark
worker gets its first preemption request (and otherwise ignores the
preemption request).

Fixes #20011.

Change-Id: I13067194b2f062b8bdef25cb75e4143b7fb6bb73
Reviewed-on: https://go-review.googlesource.com/46610
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2017-06-26 19:25:26 +00:00
Ian Lance Taylor
8ec7a39fec os/signal: avoid race between Stop and receiving on channel
When Stop is called on a channel, wait until all signals have been
delivered to the channel before returning.

Use atomic operations in sigqueue to communicate more reliably between
the os/signal goroutine and the signal handler.

Fixes #14571

Change-Id: I6c5a9eea1cff85e37a34dffe96f4bb2699e12c6e
Reviewed-on: https://go-review.googlesource.com/46003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-06-24 00:54:01 +00:00
Hiroshi Ioka
c4e0e81653 runtime/cgo: fix typos
Change-Id: I6265ac81e5c38b201e14ddba2d6b9f0e73d8445c
Reviewed-on: https://go-review.googlesource.com/46310
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-06-21 15:54:38 +00:00
Mikio Hara
7b659eb155 all: gofmt
Change-Id: I2d0439a9f068e726173afafe2ef1f5d62b7feb4d
Reviewed-on: https://go-review.googlesource.com/46190
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-06-21 03:14:30 +00:00
John R. Lenton
91139b87f7 runtime, syscall: workaround for bug in Linux's execve
Linux's execve has (at the time of writing, and since v2.6.30) a bug when it ran
concurrently with clone, in that it would fail to set up some datastructures if
the thread count before and after some steps differed. This is described better
and in more detail by Colin King in Launchpad¹ and kernel² bugs. When a program
written in Go runtime.Exec's a setuid binary, this issue may cause the resulting
process to not have the expected uid. This patch works around the issue by using
a mutex to serialize exec and clone.

1. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1672819
2. https://bugzilla.kernel.org/show_bug.cgi?id=195453

Fixes #19546

Change-Id: I126e87d1d9ce3be5ea4ec9c7ffe13f92e087903d
Reviewed-on: https://go-review.googlesource.com/43713
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-06-20 23:53:17 +00:00
Ian Lance Taylor
09ebbf4085 runtime: add read/write mutex type
This is a runtime version of sync.RWMutex that can be used by code in
the runtime package. The type is not quite the same, in that the zero
value is not valid.

For future use by CL 43713.

Updates #19546

Change-Id: I431eb3688add16ce1274dab97285f555b72735bf
Reviewed-on: https://go-review.googlesource.com/45991
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2017-06-19 17:40:38 +00:00
Vladimir Stefanovic
023593d0a8 runtime: enable GDB tests on mips64 (except TestGdbPythonCgo)
They were failing when run on 32bit RFS, with 32bit gdb.
(mips64 builder now has 64bit RFS, with gdb 7.9.)
Leaving TestGdbPythonCgo disabled, it behaves as described in #18784.

Fixes #18173

Change-Id: I3c438cd5850b7bfd118ac6396f40c1208bac8c2d
Reviewed-on: https://go-review.googlesource.com/45874
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-06-15 15:52:05 +00:00
Keith Randall
79d05e75ca runtime: restore arm assembly stubs for div/mod
These are used by DIV[U] and MOD[U] assembly instructions.
Add a test in the stdlib so we actually exercise linking
to these routines.

Update #19507

Change-Id: I0d8e19a53e3744abc0c661ea95486f94ec67585e
Reviewed-on: https://go-review.googlesource.com/45703
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-06-15 03:51:03 +00:00
Keith Randall
4958f9e2fe runtime: remove unused arm assembly for div/mod
Also add runtime· prefixes to the code that is still used.

Fixes #19507

Change-Id: Ib6da6b2a9e398061d3f93958ee1258295b6cc33b
Reviewed-on: https://go-review.googlesource.com/45699
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-06-14 18:00:26 +00:00
Ian Lance Taylor
03a4a5c988 runtime: don't run TestCgoNumGoroutine on Windows or Plan 9
The test requires pthreads.

Fixes #20666.

Change-Id: Icb2400250a80cdad6680cd1ef6c18ef7343d5e29
Reviewed-on: https://go-review.googlesource.com/45701
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-06-14 17:28:02 +00:00