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Go's dev.typeparams branch already claims to be Go 1.18, so our !go1.18 build
tags breaking testing gVisor with that branch.
Normally I would not want to bump the build tags this early, but I plan to
extend checklinkname to check the assumptions in these files and remove the
build tags ASAP. So we just go ahead and bump the tags until then to unblock
testing.
PiperOrigin-RevId: 389037239
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This CL introduces a 'checklinkname' analyzer, which provides rudimentary
type-checking that verifies that function signatures on the local and remote
sides of //go:linkname directives match expected values.
If the Go standard library changes the definitions of any of these function,
checklinkname will flag the change as a finding, providing an error informing
the gVisor team to adapt to the upstream changes. This allows us to eliminate
the majority of gVisor's forward-looking negative build tags, as we can catch
mismatches in testing [1].
The remaining forward-looking negative build tags are covering shared struct
definitions, which I hope to add to checklinkname in a future CL.
[1] Of course, semantics/requirements can change without the signature
changing, so we still must be careful, but this covers the common case.
PiperOrigin-RevId: 387873847
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PiperOrigin-RevId: 385894869
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This change makes the checklocks analyzer considerable more powerful, adding:
* The ability to traverse complex structures, e.g. to have multiple nested
fields as part of the annotation.
* The ability to resolve simple anonymous functions and closures, and perform
lock analysis across these invocations. This does not apply to closures that
are passed elsewhere, since it is not possible to know the context in which
they might be invoked.
* The ability to annotate return values in addition to receivers and other
parameters, with the same complex structures noted above.
* Ignoring locking semantics for "fresh" objects, i.e. objects that are
allocated in the local frame (typically a new-style function).
* Sanity checking of locking state across block transitions and returns, to
ensure that no unexpected locks are held.
Note that initially, most of these findings are excluded by a comprehensive
nogo.yaml. The findings that are included are fundamental lock violations.
The changes here should be relatively low risk, minor refactorings to either
include necessary annotations to simplify the code structure (in general
removing closures in favor of methods) so that the analyzer can be easily
track the lock state.
This change additional includes two changes to nogo itself:
* Sanity checking of all types to ensure that the binary and ast-derived
types have a consistent objectpath, to prevent the bug above from occurring
silently (and causing much confusion). This also requires a trick in
order to ensure that serialized facts are consumable downstream. This can
be removed with https://go-review.googlesource.com/c/tools/+/331789 merged.
* A minor refactoring to isolation the objdump settings in its own package.
This was originally used to implement the sanity check above, but this
information is now being passed another way. The minor refactor is preserved
however, since it cleans up the code slightly and is minimal risk.
PiperOrigin-RevId: 382613300
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The presence of multiple packages in a single directory sometimes
confuses `go mod`, producing output like:
go: downloading gvisor.dev/gvisor v0.0.0-20210601174640-77dc0f5bc94d
$GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/linewriter/linewriter.go:21:2: found packages sync (aliases.go) and seqatomic (generic_atomicptr_unsafe.go) in $GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/sync
imports.go:67:2: found packages tcp (accept.go) and rcv (rcv_test.go) in $GOMODCACHE/gvisor.dev/gvisor@v0.0.0-20210601174640-77dc0f5bc94d/pkg/tcpip/transport/tcp
PiperOrigin-RevId: 376956213
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Signed-off-by: Koichi Shiraishi <zchee.io@gmail.com>
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PiperOrigin-RevId: 368470656
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This validates that struct fields if annotated with "// checklocks:mu" where
"mu" is a mutex field in the same struct then access to the field is only
done with "mu" locked.
All types that are guarded by a mutex must be annotated with
// +checklocks:<mutex field name>
For more details please refer to README.md.
PiperOrigin-RevId: 360729328
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- Use atomic add rather than CAS in every Gate method, which is slightly
faster in most cases.
- Implement Close wakeup using gopark/goready to avoid channel allocation.
New benchmarks:
name old time/op new time/op delta
GateEnterLeave-12 16.7ns ± 1% 10.3ns ± 1% -38.44% (p=0.000 n=9+8)
GateClose-12 50.2ns ± 8% 42.4ns ± 6% -15.44% (p=0.000 n=10+10)
GateEnterLeaveAsyncClose-12 972ns ± 2% 640ns ± 7% -34.15% (p=0.000 n=9+10)
PiperOrigin-RevId: 359336344
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These are bumped to allow early testing of Go 1.17. Use will be audited closer
to the 1.17 release.
PiperOrigin-RevId: 358278615
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See https://github.com/golang/go/issues/19367 for rationale. Note that the
upstream decision arrived at in that thread, while useful for some of our use
cases, doesn't account for all of our SliceHeader use cases (we often use
SliceHeader to extract pointers from slices in a way that avoids bounds
checking and/or handles nil slices correctly) and also doesn't exist yet.
PiperOrigin-RevId: 358071574
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PiperOrigin-RevId: 354327882
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PiperOrigin-RevId: 347047550
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AtomicPtrMap is a generic concurrent map from arbitrary keys to arbitrary
pointer values.
Benchmarks:
name time/op
StoreDelete/RWMutexMap-12 335ns ± 1%
StoreDelete/SyncMap-12 705ns ± 3%
StoreDelete/AtomicPtrMap-12 287ns ± 4%
StoreDelete/AtomicPtrMapSharded-12 289ns ± 1%
LoadOrStoreDelete/RWMutexMap-12 342ns ± 2%
LoadOrStoreDelete/SyncMap-12 662ns ± 2%
LoadOrStoreDelete/AtomicPtrMap-12 290ns ± 7%
LoadOrStoreDelete/AtomicPtrMapSharded-12 293ns ± 2%
LookupPositive/RWMutexMap-12 101ns ±26%
LookupPositive/SyncMap-12 202ns ± 2%
LookupPositive/AtomicPtrMap-12 71.1ns ± 2%
LookupPositive/AtomicPtrMapSharded-12 73.2ns ± 1%
LookupNegative/RWMutexMap-12 119ns ± 1%
LookupNegative/SyncMap-12 154ns ± 1%
LookupNegative/AtomicPtrMap-12 84.7ns ± 3%
LookupNegative/AtomicPtrMapSharded-12 86.8ns ± 1%
Concurrent/FixedKeys_1PercentWrites_RWMutexMap-12 1.32µs ± 2%
Concurrent/FixedKeys_1PercentWrites_SyncMap-12 52.7ns ±10%
Concurrent/FixedKeys_1PercentWrites_AtomicPtrMap-12 31.8ns ±20%
Concurrent/FixedKeys_1PercentWrites_AtomicPtrMapSharded-12 24.0ns ±15%
Concurrent/FixedKeys_10PercentWrites_RWMutexMap-12 860ns ± 3%
Concurrent/FixedKeys_10PercentWrites_SyncMap-12 68.8ns ±20%
Concurrent/FixedKeys_10PercentWrites_AtomicPtrMap-12 98.6ns ± 7%
Concurrent/FixedKeys_10PercentWrites_AtomicPtrMapSharded-12 42.0ns ±25%
Concurrent/FixedKeys_50PercentWrites_RWMutexMap-12 1.17µs ± 3%
Concurrent/FixedKeys_50PercentWrites_SyncMap-12 136ns ±34%
Concurrent/FixedKeys_50PercentWrites_AtomicPtrMap-12 286ns ± 3%
Concurrent/FixedKeys_50PercentWrites_AtomicPtrMapSharded-12 115ns ±35%
Concurrent/ChangingKeys_1PercentWrites_RWMutexMap-12 1.27µs ± 2%
Concurrent/ChangingKeys_1PercentWrites_SyncMap-12 5.01µs ± 3%
Concurrent/ChangingKeys_1PercentWrites_AtomicPtrMap-12 38.1ns ± 3%
Concurrent/ChangingKeys_1PercentWrites_AtomicPtrMapSharded-12 22.6ns ± 2%
Concurrent/ChangingKeys_10PercentWrites_RWMutexMap-12 1.08µs ± 2%
Concurrent/ChangingKeys_10PercentWrites_SyncMap-12 5.97µs ± 1%
Concurrent/ChangingKeys_10PercentWrites_AtomicPtrMap-12 390ns ± 2%
Concurrent/ChangingKeys_10PercentWrites_AtomicPtrMapSharded-12 93.6ns ± 1%
Concurrent/ChangingKeys_50PercentWrites_RWMutexMap-12 1.77µs ± 2%
Concurrent/ChangingKeys_50PercentWrites_SyncMap-12 8.07µs ± 2%
Concurrent/ChangingKeys_50PercentWrites_AtomicPtrMap-12 1.61µs ± 2%
Concurrent/ChangingKeys_50PercentWrites_AtomicPtrMapSharded-12 386ns ± 1%
Updates #231
PiperOrigin-RevId: 346614776
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Per runtime.memmove, pointers are always copied atomically, as this is required
by the GC. (Also, the init() safety check doesn't work because it gets renamed
to <prefix>init() by template instantiation.)
PiperOrigin-RevId: 345800302
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This is the RWMutex equivalent to the preceding sync.Mutex CL.
Updates #4804
PiperOrigin-RevId: 345681051
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PiperOrigin-RevId: 345359823
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This function does not exist in Go 1.13. We need to add an adaptor
to build against Go 1.13, which is the default Ubuntu version.
PiperOrigin-RevId: 343929132
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We would like to track locks ordering to detect ordering violations. Detecting
violations is much simpler if mutexes must be unlocked by the same goroutine
that locked them.
Thus, as a first step to tracking lock ordering, add this lock/unlock
requirement to gVisor's sync.Mutex. This is more strict than the Go standard
library's sync.Mutex, but initial testing indicates only a single lock that is
used across goroutines. The new sync.CrossGoroutineMutex relaxes the
requirement (but will not provide lock order checking).
Due to the additional overhead, enforcement is only enabled with the
"checklocks" build tag. Build with this tag using:
bazel build --define=gotags=checklocks ...
From my spot-checking, this has no changed inlining properties when disabled.
Updates #4804
PiperOrigin-RevId: 343370200
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PiperOrigin-RevId: 329801584
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- Make sync.SeqCountEpoch not a struct. This allows sync.SeqCount.BeginRead()
to be inlined.
- Mark sync.SeqAtomicLoad<T> nosplit to mitigate the Go compiler's refusal to
inline it. (Best I could get was "cost 92 exceeds budget 80".)
- Use runtime-guided spinning in SeqCount.BeginRead().
Benchmarks:
name old time/op new time/op delta
pkg:pkg/sync/sync goos:linux goarch:amd64
SeqCountWriteUncontended-12 8.24ns ± 0% 11.40ns ± 0% +38.35% (p=0.000 n=10+10)
SeqCountReadUncontended-12 0.33ns ± 0% 0.14ns ± 3% -57.77% (p=0.000 n=7+8)
pkg:pkg/sync/seqatomictest/seqatomic goos:linux goarch:amd64
SeqAtomicLoadIntUncontended-12 0.64ns ± 1% 0.41ns ± 1% -36.40% (p=0.000 n=10+8)
SeqAtomicTryLoadIntUncontended-12 0.18ns ± 4% 0.18ns ± 1% ~ (p=0.206 n=10+8)
AtomicValueLoadIntUncontended-12 0.27ns ± 3% 0.27ns ± 0% -1.77% (p=0.000 n=10+8)
(atomic.Value.Load is, of course, inlined. We would expect an uncontended
inline SeqAtomicLoad<int> to perform identically to SeqAtomicTryLoad<int>.) The
"regression" in BenchmarkSeqCountWriteUncontended, despite this CL changing
nothing in that path, is attributed to microarchitectural subtlety; the
benchmark loop is unchanged except for its address:
Before this CL:
:0 0x4e62d1 48ffc2 INCQ DX
:0 0x4e62d4 48399110010000 CMPQ DX, 0x110(CX)
:0 0x4e62db 7e26 JLE 0x4e6303
:0 0x4e62dd 90 NOPL
:0 0x4e62de bb01000000 MOVL $0x1, BX
:0 0x4e62e3 f00fc118 LOCK XADDL BX, 0(AX)
:0 0x4e62e7 ffc3 INCL BX
:0 0x4e62e9 0fbae300 BTL $0x0, BX
:0 0x4e62ed 733a JAE 0x4e6329
:0 0x4e62ef 90 NOPL
:0 0x4e62f0 bb01000000 MOVL $0x1, BX
:0 0x4e62f5 f00fc118 LOCK XADDL BX, 0(AX)
:0 0x4e62f9 ffc3 INCL BX
:0 0x4e62fb 0fbae300 BTL $0x0, BX
:0 0x4e62ff 73d0 JAE 0x4e62d1
After this CL:
:0 0x4e6361 48ffc2 INCQ DX
:0 0x4e6364 48399110010000 CMPQ DX, 0x110(CX)
:0 0x4e636b 7e26 JLE 0x4e6393
:0 0x4e636d 90 NOPL
:0 0x4e636e bb01000000 MOVL $0x1, BX
:0 0x4e6373 f00fc118 LOCK XADDL BX, 0(AX)
:0 0x4e6377 ffc3 INCL BX
:0 0x4e6379 0fbae300 BTL $0x0, BX
:0 0x4e637d 733a JAE 0x4e63b9
:0 0x4e637f 90 NOPL
:0 0x4e6380 bb01000000 MOVL $0x1, BX
:0 0x4e6385 f00fc118 LOCK XADDL BX, 0(AX)
:0 0x4e6389 ffc3 INCL BX
:0 0x4e638b 0fbae300 BTL $0x0, BX
:0 0x4e638f 73d0 JAE 0x4e6361
PiperOrigin-RevId: 329754148
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This enables pre-release testing with 1.16. The intention is to replace these
with a nogo check before the next release.
PiperOrigin-RevId: 328193911
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sleep.Waker's fields are modified as values.
PiperOrigin-RevId: 320873451
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None of the dependencies have changed in 1.15. It may be possible to simplify
some of the wrappers in rawfile following 1.13, but that can come in a later
change.
PiperOrigin-RevId: 313863264
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These packages don't actually use go_stateify or go_marshal, but end
up implicitly dependent on the respective packages due to our build
rules.
These unnecessary dependencies make them unusuable in certain contexts
due to circular dependency.
PiperOrigin-RevId: 312595738
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PiperOrigin-RevId: 304447031
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PiperOrigin-RevId: 302924789
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