aboutsummaryrefslogtreecommitdiff
path: root/src/runtime/export_test.go
AgeCommit message (Collapse)Author
2021-11-29runtime: fix preemption sensitivity in TestTinyAllocIssue37262Austin Clements
TestTinyAllocIssue37262 assumes that all of its allocations will come from the same tiny allocator (that is, the same P), and that nothing else will allocate from that tiny allocator while it's running. It can fail incorrectly if these assumptions aren't met. Fix this potential test flakiness by disabling preemption during this test. As far as I know, this has never happened on the builders. It was found by mayMoreStackPreempt. Change-Id: I59f993e0bdbf46a9add842d0e278415422c3f804 Reviewed-on: https://go-review.googlesource.com/c/go/+/366994 Trust: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2021-11-05runtime: don't hold the heap lock while scavengingMichael Anthony Knyszek
This change modifies the scavenger to no longer hold the heap lock while actively scavenging pages. To achieve this, the change also: * Reverses the locking behavior of the (*pageAlloc).scavenge API, to only acquire the heap lock when necessary. * Introduces a new lock on the scavenger-related fields in a pageAlloc so that access to those fields doesn't require the heap lock. There are a few places in the scavenge path, notably reservation, that requires synchronization. The heap lock is far too heavy handed for this case. * Changes the scavenger to marks pages that are actively being scavenged as allocated, and "frees" them back to the page allocator the usual way. * Lifts the heap-growth scavenging code out of mheap.grow, where the heap lock is held, and into allocSpan, just after the lock is released. Releasing the lock during mheap.grow is not feasible if we want to ensure that allocation always makes progress (post-growth, another allocator could come in and take all that space, forcing the goroutine that just grew the heap to do so again). This change means that the scavenger now must do more work for each scavenge, but it is also now much more scalable. Although in theory it's not great by always taking the locked paths in the page allocator, it takes advantage of some properties of the allocator: * Most of the time, the scavenger will be working with one page at a time. The page allocator's locked path is optimized for this case. * On the allocation path, it doesn't need to do the find operation at all; it can go straight to setting bits for the range and updating the summary structure. Change-Id: Ie941d5e7c05dcc96476795c63fef74bcafc2a0f1 Reviewed-on: https://go-review.googlesource.com/c/go/+/353974 Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2021-11-04runtime: implement GC pacer redesignMichael Anthony Knyszek
This change implements the GC pacer redesign outlined in #44167 and the accompanying design document, behind a GOEXPERIMENT flag that is on by default. In addition to adding the new pacer, this CL also includes code to track and account for stack and globals scan work in the pacer and in the assist credit system. The new pacer also deviates slightly from the document in that it increases the bound on the minimum trigger ratio from 0.6 (scaled by GOGC) to 0.7. The logic behind this change is that the new pacer much more consistently hits the goal (good!) leading to slightly less frequent GC cycles, but _longer_ ones (in this case, bad!). It turns out that the cost of having the GC on hurts throughput significantly (per byte of memory used), though tail latencies can improve by up to 10%! To be conservative, this change moves the value to 0.7 where there is a small improvement to both throughput and latency, given the memory use. Because the new pacer accounts for the two most significant sources of scan work after heap objects, it is now also safer to reduce the minimum heap size without leading to very poor amortization. This change thus decreases the minimum heap size to 512 KiB, which corresponds to the fact that the runtime has around 200 KiB of scannable globals always there, up-front, providing a baseline. Benchmark results: https://perf.golang.org/search?q=upload:20211001.6 tile38's KNearest benchmark shows a memory increase, but throughput (and latency) per byte of memory used is better. gopher-lua showed an increase in both CPU time and memory usage, but subsequent attempts to reproduce this behavior are inconsistent. Sometimes the overall performance is better, sometimes it's worse. This suggests that the benchmark is fairly noisy in a way not captured by the benchmarking framework itself. biogo-igor is the only benchmark to show a significant performance loss. This benchmark exhibits a very high GC rate, with relatively little work to do in each cycle. The idle mark workers are quite active. In the new pacer, mark phases are longer, mark assists are fewer, and some of that time in mark assists has shifted to idle workers. Linux perf indicates that the difference in CPU time can be mostly attributed to write-barrier slow path related calls, which in turn indicates that the write barrier being on for longer is the primary culprit. This also explains the memory increase, as a longer mark phase leads to more memory allocated black, surviving an extra cycle and contributing to the heap goal. For #44167. Change-Id: I8ac7cfef7d593e4a642c9b2be43fb3591a8ec9c4 Reviewed-on: https://go-review.googlesource.com/c/go/+/309869 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2021-11-01runtime: disable pacer lock held assertions in testsMichael Anthony Knyszek
Fixes #49234. Change-Id: I64c1eab0dce2bbe990343b43a32858a6c9f3dcda Reviewed-on: https://go-review.googlesource.com/c/go/+/359878 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2021-10-29runtime: add testing framework and basic tests for GC pacerMichael Knyszek
This change creates a formal exported interface for the GC pacer and creates tests for it that simulate some series of GC cycles. The tests are completely driven by the real pacer implementation, except for assists, which are idealized (though revise is called repeatedly). For #44167. Change-Id: I0112242b07e7702595ca71001d781ad6c1fddd2d Reviewed-on: https://go-review.googlesource.com/c/go/+/353354 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-10-20runtime: retype mheap.pagesInUse as atomic.Uint64Michael Anthony Knyszek
[git-generate] cd src/runtime mv export_test.go export.go GOROOT=$(dirname $(dirname $PWD)) rf ' add mheap.pagesInUse \ // Proportional sweep \ // \ // These parameters represent a linear function from gcController.heapLive \ // to page sweep count. The proportional sweep system works to \ // stay in the black by keeping the current page sweep count \ // above this line at the current gcController.heapLive. \ // \ // The line has slope sweepPagesPerByte and passes through a \ // basis point at (sweepHeapLiveBasis, pagesSweptBasis). At \ // any given time, the system is at (gcController.heapLive, \ // pagesSwept) in this space. \ // \ // It is important that the line pass through a point we \ // control rather than simply starting at a 0,0 origin \ // because that lets us adjust sweep pacing at any time while \ // accounting for current progress. If we could only adjust \ // the slope, it would create a discontinuity in debt if any \ // progress has already been made. \ pagesInUse_ atomic.Uint64 // pages of spans in stats mSpanInUse ex { import "runtime/internal/atomic" var t mheap var v, w uint64 var d int64 t.pagesInUse -> t.pagesInUse_.Load() t.pagesInUse = v -> t.pagesInUse_.Store(v) atomic.Load64(&t.pagesInUse) -> t.pagesInUse_.Load() atomic.LoadAcq64(&t.pagesInUse) -> t.pagesInUse_.LoadAcquire() atomic.Store64(&t.pagesInUse, v) -> t.pagesInUse_.Store(v) atomic.StoreRel64(&t.pagesInUse, v) -> t.pagesInUse_.StoreRelease(v) atomic.Cas64(&t.pagesInUse, v, w) -> t.pagesInUse_.CompareAndSwap(v, w) atomic.Xchg64(&t.pagesInUse, v) -> t.pagesInUse_.Swap(v) atomic.Xadd64(&t.pagesInUse, d) -> t.pagesInUse_.Add(d) } rm mheap.pagesInUse mv mheap.pagesInUse_ mheap.pagesInUse ' mv export.go export_test.go Change-Id: I495d188683dba0778518563c46755b5ad43be298 Reviewed-on: https://go-review.googlesource.com/c/go/+/356549 Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Austin Clements <austin@google.com>
2021-09-02runtime: constify a test variableCarlo Alberto Ferraris
Simple cleanup, no functionality change. Change-Id: I8eceda4496a396e0117a0a601186c653982fb004 GitHub-Last-Rev: 58defc575e5834a3685bbb8179fdee4afa8d8fc7 GitHub-Pull-Request: golang/go#47389 Reviewed-on: https://go-review.googlesource.com/c/go/+/337289 Reviewed-by: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Cherry Mui <cherryyz@google.com>
2021-06-17[dev.typeparams] runtime: replace Goos* constants with internal/goos ↵Michael Anthony Knyszek
versions [generated] [git-generate] cd src/runtime gofmt -w -r "sys.GoosAix -> goos.IsAix" . gofmt -w -r "sys.GoosAndroid -> goos.IsAndroid" . gofmt -w -r "sys.GoosDarwin -> goos.IsDarwin" . gofmt -w -r "sys.GoosDragonfly -> goos.IsDragonfly" . gofmt -w -r "sys.GoosFreebsd -> goos.IsFreebsd" . gofmt -w -r "sys.GoosHurd -> goos.IsHurd" . gofmt -w -r "sys.GoosIllumos -> goos.IsIllumos" . gofmt -w -r "sys.GoosIos -> goos.IsIos" . gofmt -w -r "sys.GoosJs -> goos.IsJs" . gofmt -w -r "sys.GoosLinux -> goos.IsLinux" . gofmt -w -r "sys.GoosNacl -> goos.IsNacl" . gofmt -w -r "sys.GoosNetbsd -> goos.IsNetbsd" . gofmt -w -r "sys.GoosOpenbsd -> goos.IsOpenbsd" . gofmt -w -r "sys.GoosPlan9 -> goos.IsPlan9" . gofmt -w -r "sys.GoosSolaris -> goos.IsSolaris" . gofmt -w -r "sys.GoosWindows -> goos.IsWindows" . gofmt -w -r "sys.GoosZos -> goos.IsZos" . goimports -w *.go Change-Id: I42bed2907317ed409812e5a3e2897c88a5d36f24 Reviewed-on: https://go-review.googlesource.com/c/go/+/328344 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2021-06-17[dev.typeparams] runtime,runtime/internal/sys: remove unused BigEndianMichael Anthony Knyszek
Change-Id: I1209904326b1563e12d9c7d19a12a10c72d1dbcb Reviewed-on: https://go-review.googlesource.com/c/go/+/329191 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-06-17[dev.typeparams] runtime/internal/sys: replace BigEndian with ↵Michael Anthony Knyszek
goarch.BigEndian [generated] [git-generate] cd src/runtime/internal/atomic gofmt -w -r "sys.BigEndian -> goarch.BigEndian" . goimports -w *.go cd ../.. gofmt -w -r "sys.BigEndian -> goarch.BigEndian" . goimports -w *.go Change-Id: Iad35d2b367d8defb081a77ca837e7a7c805c2b7b Reviewed-on: https://go-review.googlesource.com/c/go/+/329190 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-06-17[dev.typeparams] runtime: fix import sort order [generated]Michael Anthony Knyszek
[git-generate] cd src/runtime goimports -w *.go Change-Id: I1387af0f2fd1a213dc2f4c122e83a8db0fcb15f0 Reviewed-on: https://go-review.googlesource.com/c/go/+/329189 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-06-17[dev.typeparams] runtime: replace uses of runtime/internal/sys.PtrSize with ↵Michael Anthony Knyszek
internal/goarch.PtrSize [generated] [git-generate] cd src/runtime/internal/math gofmt -w -r "sys.PtrSize -> goarch.PtrSize" . goimports -w *.go cd ../.. gofmt -w -r "sys.PtrSize -> goarch.PtrSize" . goimports -w *.go Change-Id: I43491cdd54d2e06d4d04152b3d213851b7d6d423 Reviewed-on: https://go-review.googlesource.com/c/go/+/328337 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2021-06-04[dev.typeparams] runtime: undo go'd closure argument workaroundCherry Mui
In CL 298669 we added defer/go wrapping, and, as it is not allowed for closures to escape when compiling runtime, we worked around it by rewriting go'd closures to argumentless non-capturing closures, so it is not a real closure and so not needed to escape. Previous CL removes the restriction. Now we can undo the workaround. Updates #40724. Change-Id: Ic7bf129da4aee7b7fdb7157414eca943a6a27264 Reviewed-on: https://go-review.googlesource.com/c/go/+/325110 Trust: Cherry Mui <cherryyz@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
2021-05-25[dev.typeparams] all: merge master (f22ec51) into dev.typeparamsMatthew Dempsky
Merge List: + 2021-05-25 f22ec51deb doc: add Go 1.17 release note about inlining functions with closures + 2021-05-25 8b462d7567 cmd/go: add a -compat flag to 'go mod tidy' + 2021-05-24 c89f1224a5 net: verify results from Lookup* are valid domain names + 2021-05-24 08a8fa9c47 misc/wasm: ensure correct stack pointer in catch clauses + 2021-05-24 32b73ae180 cmd/go: align checks of module path during initialization. + 2021-05-24 15d9d4a009 cmd/go: add tests illustrating what happens when Go 1.16 is used in a Go 1.17 main module + 2021-05-24 873401df5b cmd/compile: ensure equal functions don't do unaligned loads + 2021-05-24 b83610699a cmd/compile: record regabi status in DW_AT_producer + 2021-05-24 a22e317220 cmd/compile: always include underlying type for map types + 2021-05-24 4356e7e85f runtime: account for spill slots in Windows callback compilation + 2021-05-24 52d7033ff6 cmd/go/internal/modload: set the default GoVersion in a single location + 2021-05-24 05819bc104 cmd/go/internal/modcmd: factor out a type for flags whose arguments are Go versions + 2021-05-22 cca23a7373 cmd/compile: revert CL/316890 + 2021-05-21 f87194cbd7 doc/go1.17: document changes to net/http package + 2021-05-21 217f5dd496 doc: document additional atomic.Value methods + 2021-05-21 3c656445f1 cmd/go: in TestScript/mod_replace, download an explicit module path + 2021-05-21 76b2d6afed os: document that StartProcess puts files into blocking mode + 2021-05-21 e4d7525c3e cmd/dist: display first class port status in json output + 2021-05-21 4fb10b2118 cmd/go: in 'go mod download' without args, don't save module zip sums + 2021-05-21 4fda54ce3f doc/go1.17: document database/sql changes for Go 1.17 + 2021-05-21 8876b9bd6a doc/go1.17: document io/fs changes for Go 1.17 + 2021-05-21 5fee772c87 doc/go1.17: document archive/zip changes for Go 1.17 + 2021-05-21 3148694f60 cmd/go: remove warning from module deprecation notice printing + 2021-05-21 7e63c8b765 runtime: wait for Go runtime to initialize in Windows signal test + 2021-05-21 831573cd21 io/fs: added an example for io/fs.WalkDir + 2021-05-20 baa934d26d cmd: go get golang.org/x/tools/analysis@49064d23 && go mod vendor + 2021-05-20 7c692cc7ea doc/go1.17: document changes to os package + 2021-05-20 ce9a3b79d5 crypto/x509: add new FreeBSD 12.2+ trusted certificate folder + 2021-05-20 f8be906d74 test: re-enable test on riscv64 now that it supports external linking + 2021-05-20 def5360541 doc/go1.17: add release notes for OpenBSD ports + 2021-05-20 ef1f52cc38 doc/go1.17: add release note for windows/arm64 port + 2021-05-20 bb7495a46d doc/go1.17: document new math constants + 2021-05-20 f07e4dae3c syscall: document NewCallback and NewCallbackCDecl limitations + 2021-05-20 a8d85918b6 misc/cgo/testplugin: skip TestIssue25756pie on darwin/arm64 builder + 2021-05-19 6c1c055d1e cmd/internal/moddeps: use filepath.SkipDir only on directories + 2021-05-19 658b5e66ec net: return nil UDPAddr from ReadFromUDP + 2021-05-19 15a374d5c1 test: check portable error message on issue46234.go + 2021-05-18 eeadce2d87 go/build/constraint: fix parsing of "// +build" (with no args) + 2021-05-18 6d2ef2ef2a cmd/compile: don't emit inltree for closure within body of inlined func + 2021-05-18 048cb4ceee crypto/x509: remove duplicate import Change-Id: Ib0442e3555493805f2aa1df26dfd6898df989a37
2021-05-24cmd/compile: always include underlying type for map typesKeith Randall
This is a different fix for #37716. Should help make the fix for #46283 easier, since we will no longer need to keep compiler-generated hash functions and the runtime hash function in sync. Change-Id: I84cb93144e425dcd03afc552b5fbd0f2d2cc6d39 Reviewed-on: https://go-review.googlesource.com/c/go/+/322150 Trust: Keith Randall <khr@golang.org> Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
2021-05-21[dev.typeparams] runtime: replace funcPC with internal/abi.FuncPCABIInternalCherry Mui
At this point all funcPC references are ABIInternal functions. Replace with the intrinsics. Change-Id: I3ba7e485c83017408749b53f92877d3727a75e27 Reviewed-on: https://go-review.googlesource.com/c/go/+/321954 Trust: Cherry Mui <cherryyz@google.com> Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
2021-04-29runtime: top align tinyallocs in race modeKeith Randall
Top align allocations in tinyalloc buckets when in race mode. This will make checkptr checks more reliable, because any code that modifies a pointer past the end of the object will trigger a checkptr error. No test, because we need -race for this to actually kick in. We could add it to the race detector tests, but the race detector tests are all geared towards race detector reports, not checkptr reports. Mucking with parsing reports is more than a test is worth. Fixes #38872 Change-Id: Ie56f0fbd1a9385539f6631fd1ac40c3de5600154 Reviewed-on: https://go-review.googlesource.com/c/go/+/315029 Trust: Keith Randall <khr@golang.org> Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com> Reviewed-by: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-04-27runtime/metrics: add tiny allocs metricMichael Anthony Knyszek
Currently tiny allocations are not represented in either MemStats or runtime/metrics, but they're represented in MemStats (indirectly) via Mallocs. Add them to runtime/metrics by first merging memstats.tinyallocs into consistentHeapStats (just for simplicity; it's monotonic so metrics would still be self-consistent if we just read it atomically) and then adding /gc/heap/tiny/allocs:objects to the list of supported metrics. Change-Id: Ie478006ab942a3e877b4a79065ffa43569722f3d Reviewed-on: https://go-review.googlesource.com/c/go/+/312909 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2021-03-31runtime: support register ABI Go functions from Windows callbacksMichael Anthony Knyszek
This change modifies the system that allows Go functions to be set as callbacks in various Windows systems to support the new register ABI. For #40724. Change-Id: Ie067f9e8a76c96d56177d7aa88f89cbe7223e12e Reviewed-on: https://go-review.googlesource.com/c/go/+/300113 Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Cherry Zhang <cherryyz@google.com> Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org>
2021-03-29runtime: add GC testing helpers for regabi signature fuzzerAustin Clements
This CL adds a set of helper functions for testing GC interactions. These are intended for use in the regabi signature fuzzer, but are generally useful for GC tests, so we make them generally available to runtime tests. These provide: 1. An easy way to force stack movement, for testing stack copying. 2. A simple and robust way to check the reachability of a set of pointers. 3. A way to check what general category of memory a pointer points to, mostly so tests can make sure they're testing what they mean to. For #40724, but generally useful. Change-Id: I15d33ccb3f5a792c0472a19c2cc9a8b4a9356a66 Reviewed-on: https://go-review.googlesource.com/c/go/+/305330 Trust: Austin Clements <austin@google.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
2021-03-23cmd/compile: wrap/desugar defer calls for register abiThan McIntosh
Adds code to the compiler's "order" phase to rewrite go and defer statements to always be argument-less. E.g. defer f(x,y) => x1, y1 := x, y defer func() { f(x1, y1) } This transformation is not beneficial on its own, but it helps simplify runtime defer handling for the new register ABI (when invoking deferred functions on the panic path, the runtime doesn't need to manage the complexity of determining which args to pass in register vs memory). This feature is currently enabled by default if GOEXPERIMENT=regabi or GOEXPERIMENT=regabidefer is in effect. Included in this CL are some workarounds in the runtime to insure that "go" statement targets in the runtime are argument-less already (since wrapping them can potentially introduce heap-allocated closures, which are currently not allowed). The expectation is that these workarounds will be temporary, and can go away once we either A) change the rules about heap-allocated closures, or B) implement some other scheme for handling go statements. Change-Id: I01060d79a6b140c6f0838d6e6813f807ccdca319 Reviewed-on: https://go-review.googlesource.com/c/go/+/298669 Trust: Than McIntosh <thanm@google.com> Run-TryBot: Than McIntosh <thanm@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: David Chase <drchase@google.com>
2021-03-15runtime: prepare arenas for use incrementallyMichael Anthony Knyszek
This change moves the call of sysMap from (*mheap).sysAlloc into (*mheap).grow, so we only sysMap what we're going to use in the near future (thanks to the curArena mechanism). The purpose of this change is to better support systems with strict overcommit rules which generally accept reserved memory but not prepared memory (see malloc.go for exact descriptions of these states). This move requires changing linearAlloc to only optionally map memory. In one case, with mheap.heapArenaAlloc, we do want it to map memory. But now in the other case, with mheap.arena, we don't, because we want grow to take care of it. The risk with this change is we may make more syscalls than before on systems with 64 MiB arenas, but because heap growth is relatively rare this is unlikely to be a noticable issue. We also bound the amount of syscalls made by only extending curArena (and thus mapping) by pallocChunkPages*pageSize which is 4 MiB. Fixes #42612. Change-Id: I736df696afe78ddb1a747a896caa0db8726027e5 Reviewed-on: https://go-review.googlesource.com/c/go/+/270537 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2021-03-11runtime: support register ABI for finalizersMichael Anthony Knyszek
This change modifies runfinq to properly pass arguments to finalizers in registers via reflectcall. For #40724. Change-Id: I414c0eff466ef315a0eb10507994e598dd29ccb2 Reviewed-on: https://go-review.googlesource.com/c/go/+/300112 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-03-10runtime: check partial lock ranking orderMichael Pratt
To ease readability we typically keep the partial order lists sorted by rank. This isn't required for correctness, it just makes it (slightly) easier to read the lists. Currently we must notice out-of-order entries during code review, which is an error-prone process. Add a test to enforce ordering, and fix the errors that have crept in. Most of the existing errors were misordered lockRankHchan or lockRankPollDesc. While we're here, I've moved the correctness check that the partial ordering satisfies the total ordering from init to a test case. This will allow us to catch these errors without even running staticlockranking. Change-Id: I9c11abe49ea26c556439822bb6a3183129600c3b Reviewed-on: https://go-review.googlesource.com/c/go/+/300171 Trust: Michael Pratt <mpratt@google.com> Trust: Dan Scales <danscales@google.com> Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>
2021-02-19runtime: document, clean up internal/sysRuss Cox
Document what the values in internal/sys mean. Remove various special cases for arm64 in the code using StackAlign. Delete Uintreg - it was for GOARCH=amd64p32, which was specific to GOOS=nacl and has been retired. This CL is part of a stack adding windows/arm64 support (#36439), intended to land in the Go 1.17 cycle. This CL is, however, not windows/arm64-specific. It is cleanup meant to make the port (and future ports) easier. Change-Id: I40e8fa07b4e192298b6536b98a72a751951a4383 Reviewed-on: https://go-review.googlesource.com/c/go/+/288795 Trust: Russ Cox <rsc@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-12-23runtime: shift timeHistogram buckets and allow negative durationsMichael Anthony Knyszek
Today, timeHistogram, when copied, has the wrong set of counts for the bucket that should represent (-inf, 0), when in fact it contains [0, 1). In essence, the buckets are all shifted over by one from where they're supposed to be. But this also means that the existence of the overflow bucket is wrong: the top bucket is supposed to extend to infinity, and what we're really missing is an underflow bucket to represent the range (-inf, 0). We could just always zero this bucket and continue ignoring negative durations, but that likely isn't prudent. timeHistogram is intended to be used with differences in nanotime, but depending on how a platform is implemented (or due to a bug in that platform) it's possible to get a negative duration without having done anything wrong. We should just be resilient to that and be able to detect it. So this change removes the overflow bucket and replaces it with an underflow bucket, and timeHistogram no longer panics when faced with a negative duration. Fixes #43328. Fixes #43329. Change-Id: If336425d7d080fd37bf071e18746800e22d38108 Reviewed-on: https://go-review.googlesource.com/c/go/+/279468 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-30runtime: add heap lock assertionsMichael Pratt
Some functions that required holding the heap lock _or_ world stop have been simplified to simply requiring the heap lock. This is conceptually simpler and taking the heap lock during world stop is guaranteed to not contend. This was only done on functions already called on the systemstack to avoid too many extra systemstack calls in GC. Updates #40677 Change-Id: I15aa1dadcdd1a81aac3d2a9ecad6e7d0377befdc Reviewed-on: https://go-review.googlesource.com/c/go/+/250262 Run-TryBot: Michael Pratt <mpratt@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Trust: Michael Pratt <mpratt@google.com>
2020-10-26runtime: add timeHistogram typeMichael Anthony Knyszek
This change adds a concurrent HDR time histogram to the runtime with tests. It also adds a function to generate boundaries for use by the metrics package. For #37112. Change-Id: Ifbef8ddce8e3a965a0dcd58ccd4915c282ae2098 Reviewed-on: https://go-review.googlesource.com/c/go/+/247046 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-26runtime,runtime/metrics: add memory metricsMichael Anthony Knyszek
This change adds support for a variety of runtime memory metrics and contains the base implementation of Read for the runtime/metrics package, which lives in the runtime. It also adds testing infrastructure for the metrics package, and a bunch of format and documentation tests. For #37112. Change-Id: I16a2c4781eeeb2de0abcb045c15105f1210e2d8a Reviewed-on: https://go-review.googlesource.com/c/go/+/247041 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Trust: Michael Knyszek <mknyszek@google.com>
2020-10-26runtime: move malloc stats into consistentHeapStatsMichael Anthony Knyszek
This change moves the mcache-local malloc stats into the consistentHeapStats structure so the malloc stats can be managed consistently with the memory stats. The one exception here is tinyAllocs for which moving that into the global stats would incur several atomic writes on the fast path. Microbenchmarks for just one CPU core have shown a 50% loss in throughput. Since tiny allocation counnt isn't exposed anyway and is always blindly added to both allocs and frees, let that stay inconsistent and flush the tiny allocation count every so often. Change-Id: I2a4b75f209c0e659b9c0db081a3287bf227c10ca Reviewed-on: https://go-review.googlesource.com/c/go/+/247039 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-26runtime: delineate which memstats are system stats with a typeMichael Anthony Knyszek
This change modifies the type of several mstats fields to be a new type: sysMemStat. This type has the same structure as the fields used to have. The purpose of this change is to make it very clear which stats may be used in various functions for accounting (usually the platform-specific sys* functions, but there are others). Currently there's an implicit understanding that the *uint64 value passed to these functions is some kind of statistic whose value is atomically managed. This understanding isn't inherently problematic, but we're about to change how some stats (which currently use mSysStatInc and mSysStatDec) work, so we want to make it very clear what the various requirements are around "sysStat". This change also removes mSysStatInc and mSysStatDec in favor of a method on sysMemStat. Note that those two functions were originally written the way they were because atomic 64-bit adds required a valid G on ARM, but this hasn't been the case for a very long time (since golang.org/cl/14204, but even before then it wasn't clear if mutexes required a valid G anymore). Today we implement 64-bit adds on ARM with a spinlock table. Change-Id: I4e9b37cf14afc2ae20cf736e874eb0064af086d7 Reviewed-on: https://go-review.googlesource.com/c/go/+/246971 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-26runtime: rename mcache fields to match Go styleMichael Anthony Knyszek
This change renames a bunch of malloc statistics stored in the mcache that are all named with the "local_" prefix. It also renames largeAlloc to allocLarge to prevent a naming conflict, and next_sample because it would be the last mcache field with the old C naming style. Change-Id: I29695cb83b397a435ede7e9ad5c3c9be72767ea3 Reviewed-on: https://go-review.googlesource.com/c/go/+/246969 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-26runtime: don't flush local_tinyallocsMichael Anthony Knyszek
This change makes local_tinyallocs work like the rest of the malloc stats and doesn't flush local_tinyallocs, instead making that the source-of-truth. Change-Id: I3e6cb5f1b3d086e432ce7d456895511a48e3617a Reviewed-on: https://go-review.googlesource.com/c/go/+/246967 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-26runtime: make distributed/local malloc stats the source-of-truthMichael Anthony Knyszek
This change makes it so that various local malloc stats (excluding heap_scan and local_tinyallocs) are no longer written first to mheap fields but are instead accessed directly from each mcache. This change is part of a move toward having stats be distributed, and cleaning up some old code related to the stats. Note that because there's no central source-of-truth, when an mcache dies, it must donate its stats to another mcache. It's always safe to donate to the mcache for the 0th P, so do that. Change-Id: I2556093dbc27357cb9621c9b97671f3c00aa1173 Reviewed-on: https://go-review.googlesource.com/c/go/+/246964 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-23runtime: add tests for addrRanges.addMichael Anthony Knyszek
Change-Id: I249deb482df74068b0538e9d773b9a87bc5a6df3 Reviewed-on: https://go-review.googlesource.com/c/go/+/242681 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-23runtime: add tests for addrRanges.findSuccMichael Anthony Knyszek
This change adds a test suite for addrRanges.findSucc so we can change the implementation more safely. For #40191. Change-Id: I14a834b6d54836cbc676eb0edb292ba6176705cc Reviewed-on: https://go-review.googlesource.com/c/go/+/242678 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-10-22runtime: define the AddrRange used for testing in terms of addrRangeMichael Anthony Knyszek
Currently the AddrRange used for testing is defined separately from addrRange in the runtime, making it difficult to test it as well as addrRanges. Redefine AddrRange in terms of addrRange instead. For #40191. Change-Id: I3aa5b8df3e4c9a3c494b46ab802dd574b2488141 Reviewed-on: https://go-review.googlesource.com/c/go/+/242677 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com> Reviewed-by: Austin Clements <austin@google.com>
2020-09-16runtime: actually fix locking in BenchmarkMSpanCountAllocMichael Anthony Knyszek
I just submitted CL 255297 which mostly fixed this problem, but totally forgot to actually acquire/release the heap lock. Oops. Updates #41391. Change-Id: I45b42f20a9fc765c4de52476db3654d4bfe9feb3 Reviewed-on: https://go-review.googlesource.com/c/go/+/255298 Trust: Michael Knyszek <mknyszek@google.com> Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Go Bot <gobot@golang.org>
2020-09-16runtime: fix leak and locking in BenchmarkMSpanCountAllocMichael Anthony Knyszek
CL 249917 made the mspan in MSpanCountAlloc no longer stack-allocated (for good reason), but then allocated an mspan on each call and did not free it, resulting in a leak. That allocation was also not protected by the heap lock, which could lead to data corruption of mheap fields and the spanalloc. To fix this, export some functions to allocate/free dummy mspans from spanalloc (with proper locking) and allocate just one up-front for the benchmark, freeing it at the end. Then, update MSpanCountAlloc to accept a dummy mspan. Note that we need to allocate the dummy mspan up-front otherwise we measure things like heap locking and fixalloc performance instead of what we actually want to measure: how fast we can do a popcount on the mark bits. Fixes #41391. Change-Id: If6629a6ec1ece639c7fb78532045837a8c872c04 Reviewed-on: https://go-review.googlesource.com/c/go/+/255297 Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Trust: Michael Knyszek <mknyszek@google.com>
2020-09-09runtime: fix ReadMemStatsSlow's and CheckScavengedBits' chunk iterationMichael Anthony Knyszek
Both ReadMemStatsSlow and CheckScavengedBits iterate over the page allocator's chunks but don't actually check if they exist. During the development process the chunks index became sparse, so now this was a possibility. If the runtime tests' heap is sparse we might end up segfaulting in either one of these functions, though this will generally be very rare. The pattern here to return nil for a nonexistent chunk is also useful elsewhere, so this change introduces tryChunkOf which won't throw, but might return nil. It also updates the documentation of chunkOf. Fixes #41296. Change-Id: Id5ae0ca3234480de1724fdf2e3677eeedcf76fa0 Reviewed-on: https://go-review.googlesource.com/c/go/+/253777 Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-08-25cmd/compile: don't allow go:notinheap on the heap or stackKeith Randall
Right now we just prevent such types from being on the heap. This CL makes it so they cannot appear on the stack either. The distinction between heap and stack is pretty vague at the language level (e.g. it is affected by -N), and we don't need the flexibility anyway. Once go:notinheap types cannot be in either place, we don't need to consider pointers to such types to be pointers, at least according to the garbage collector and stack copying. (This is the big win of this CL, in my opinion.) The distinction between HasPointers and HasHeapPointer no longer exists. There is only HasPointers. This CL is cleanup before possible use of go:notinheap to fix #40954. Update #13386 Change-Id: Ibd895aadf001c0385078a6d4809c3f374991231a Reviewed-on: https://go-review.googlesource.com/c/go/+/249917 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
2020-08-13runtime: revert signal stack mlockingAustin Clements
Go 1.14 included a (rather awful) workaround for a Linux kernel bug that corrupted vector registers on x86 CPUs during signal delivery (https://bugzilla.kernel.org/show_bug.cgi?id=205663). This bug was introduced in Linux 5.2 and fixed in 5.3.15, 5.4.2 and all 5.5 and later kernels. The fix was also back-ported by major distros. This workaround was necessary, but had unfortunate downsides, including causing Go programs to exceed the mlock ulimit in many configurations (#37436). We're reasonably confident that by the Go 1.16 release, the number of systems running affected kernels will be vanishingly small. Hence, this CL removes this workaround. This effectively reverts CLs 209597 (version parser), 209899 (mlock top of signal stack), 210299 (better failure message), 223121 (soft mlock failure handling), and 244059 (special-case patched Ubuntu kernels). The one thing we keep is the osArchInit function. It's empty everywhere now, but is a reasonable hook to have. Updates #35326, #35777 (the original register corruption bugs). Updates #40184 (request to revert in 1.15). Fixes #35979. Change-Id: Ie213270837095576f1f3ef46bf3de187dc486c50 Reviewed-on: https://go-review.googlesource.com/c/go/+/246200 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2020-05-14runtime: make maxOffAddr reflect the actual address space upper boundMichael Anthony Knyszek
Currently maxOffAddr is defined in terms of the whole 64-bit address space, assuming that it's all supported, by using ^uintptr(0) as the maximal address in the offset space. In reality, the maximal address in the offset space is (1<<heapAddrBits)-1 because we don't have more than that actually available to us on a given platform. On most platforms this is fine, because arenaBaseOffset is just connecting two segments of address space, but on AIX we use it as an actual offset for the starting address of the available address space, which is limited. This means using ^uintptr(0) as the maximal address in the offset address space causes wrap-around, especially when we just want to represent a range approximately like [addr, infinity), which today we do by using maxOffAddr. To fix this, we define maxOffAddr more appropriately, in terms of (1<<heapAddrBits)-1. This change also redefines arenaBaseOffset to not be the negation of the virtual address corresponding to address zero in the virtual address space, but instead directly as the virtual address corresponding to zero. This matches the existing documentation more closely and makes the logic around arenaBaseOffset decidedly simpler, especially when trying to reason about its use on AIX. Fixes #38966. Change-Id: I1336e5036a39de846f64cc2d253e8536dee57611 Reviewed-on: https://go-review.googlesource.com/c/go/+/233497 Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>
2020-05-08runtime: make addrRange[s] operate on offset addressesMichael Anthony Knyszek
Currently addrRange and addrRanges operate on real addresses. That is, the addresses they manipulate don't include arenaBaseOffset. When added to an address, arenaBaseOffset makes the address space appear contiguous on platforms where the address space is segmented. While this is generally OK because even those platforms which have a segmented address space usually don't give addresses in a different segment, today it causes a mismatch between the scavenger and the rest of the page allocator. The scavenger scavenges from the highest addresses first, but only via real address, whereas the page allocator allocates memory in offset address order. So this change makes addrRange and addrRanges, i.e. what the scavenger operates on, use offset addresses. However, lots of the page allocator relies on an addrRange containing real addresses. To make this transition less error-prone, this change introduces a new type, offAddr, whose purpose is to make offset addresses a distinct type, so any attempt to trivially mix real and offset addresses will trigger a compilation error. This change doesn't attempt to use offAddr in all of the runtime; a follow-up change will look for and catch remaining uses of an offset address which doesn't use the type. Updates #35788. Change-Id: I991d891ac8ace8339ca180daafdf6b261a4d43d1 Reviewed-on: https://go-review.googlesource.com/c/go/+/230717 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2020-05-08runtime: remove scavAddr in favor of address rangesMichael Anthony Knyszek
This change removes the concept of s.scavAddr in favor of explicitly reserving and unreserving address ranges. s.scavAddr has several problems with raciness that can cause the scavenger to miss updates, or move it back unnecessarily, forcing future scavenge calls to iterate over searched address space unnecessarily. This change achieves this by replacing scavAddr with a second addrRanges which is cloned from s.inUse at the end of each sweep phase. Ranges from this second addrRanges are then reserved by scavengers (with the reservation size proportional to the heap size) who are then able to safely iterate over those ranges without worry of another scavenger coming in. Fixes #35788. Change-Id: Ief01ae170384174875118742f6c26b2a41cbb66d Reviewed-on: https://go-review.googlesource.com/c/go/+/208378 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com> Reviewed-by: Austin Clements <austin@google.com>
2020-05-07runtime/runtime2: pack the sudog structAaron Patterson
This commit moves the isSelect bool below the ticket uint32. The boolean was consuming 8 bytes of the struct. The uint32 was also consuming 8 bytes, so we can pack isSelect below the uint32 and save 8 bytes. This reduces the sudog struct from 96 bytes to 88 bytes. Change-Id: If555cdaf2f5eaa125e2590fc4d113dbc99750738 GitHub-Last-Rev: d63b4e086b17da74e185046dfecb12d58e4f19ac GitHub-Pull-Request: golang/go#36552 Reviewed-on: https://go-review.googlesource.com/c/go/+/214677 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
2020-04-07runtime: static lock ranking for the runtime (enabled by GOEXPERIMENT)Dan Scales
I took some of the infrastructure from Austin's lock logging CR https://go-review.googlesource.com/c/go/+/192704 (with deadlock detection from the logs), and developed a setup to give static lock ranking for runtime locks. Static lock ranking establishes a documented total ordering among locks, and then reports an error if the total order is violated. This can happen if a deadlock happens (by acquiring a sequence of locks in different orders), or if just one side of a possible deadlock happens. Lock ordering deadlocks cannot happen as long as the lock ordering is followed. Along the way, I found a deadlock involving the new timer code, which Ian fixed via https://go-review.googlesource.com/c/go/+/207348, as well as two other potential deadlocks. See the constants at the top of runtime/lockrank.go to show the static lock ranking that I ended up with, along with some comments. This is great documentation of the current intended lock ordering when acquiring multiple locks in the runtime. I also added an array lockPartialOrder[] which shows and enforces the current partial ordering among locks (which is embedded within the total ordering). This is more specific about the dependencies among locks. I don't try to check the ranking within a lock class with multiple locks that can be acquired at the same time (i.e. check the ranking when multiple hchan locks are acquired). Currently, I am doing a lockInit() call to set the lock rank of most locks. Any lock that is not otherwise initialized is assumed to be a leaf lock (a very high rank lock), so that eliminates the need to do anything for a bunch of locks (including all architecture-dependent locks). For two locks, root.lock and notifyList.lock (only in the runtime/sema.go file), it is not as easy to do lock initialization, so instead, I am passing the lock rank with the lock calls. For Windows compilation, I needed to increase the StackGuard size from 896 to 928 because of the new lock-rank checking functions. Checking of the static lock ranking is enabled by setting GOEXPERIMENT=staticlockranking before doing a run. To make sure that the static lock ranking code has no overhead in memory or CPU when not enabled by GOEXPERIMENT, I changed 'go build/install' so that it defines a build tag (with the same name) whenever any experiment has been baked into the toolchain (by checking Expstring()). This allows me to avoid increasing the size of the 'mutex' type when static lock ranking is not enabled. Fixes #38029 Change-Id: I154217ff307c47051f8dae9c2a03b53081acd83a Reviewed-on: https://go-review.googlesource.com/c/go/+/207619 Reviewed-by: Dan Scales <danscales@google.com> Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Dan Scales <danscales@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-03-23runtime: add countAlloc benchmarkMichael Anthony Knyszek
This change adds a small microbenchmark for (*mspan).countAlloc, which we're about to replace. Admittedly this isn't a critical piece of code, but the benchmark was useful in understanding the performance change. Change-Id: Iea93c00f571ee95534a42f2ef2ab026b382242b3 Reviewed-on: https://go-review.googlesource.com/c/go/+/224438 Run-TryBot: Michael Knyszek <mknyszek@google.com> Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com> Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2020-03-10runtime: make typehash match compiler generated hashes exactlyKeith Randall
If typehash (used by reflect) does not match the built-in map's hash, then problems occur. If a map is built using reflect, and then assigned to a variable of map type, the hash function can change. That causes very bad things. This issue is rare. MapOf consults a cache of all types that occur in the binary before making a new one. To make a true new map type (with a hash function derived from typehash) that map type must not occur in the binary anywhere. But to cause the bug, we need a variable of that type in order to assign to it. The only way to make that work is to use a named map type for the variable, so it is distinct from the unnamed version that MapOf looks for. Fixes #37716 Change-Id: I3537bfceca8cbfa1af84202f432f3c06953fe0ed Reviewed-on: https://go-review.googlesource.com/c/go/+/222357 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-01-28runtime: ensure that searchAddr always refers to inUse memoryMichael Anthony Knyszek
This change formalizes an assumption made by the page allocator, which is that (*pageAlloc).searchAddr should never refer to memory that is not represented by (*pageAlloc).inUse. The portion of address space covered by (*pageAlloc).inUse reflects the parts of the summary arrays which are guaranteed to mapped, and so looking at any summary which is not reflected there may cause a segfault. In fact, this can happen today. This change thus also removes a micro-optimization which is the only case which may cause (*pageAlloc).searchAddr to point outside of any region covered by (*pageAlloc).inUse, and adds a test verifying that the current segfault can no longer occur. Change-Id: I98b534f0ffba8656d3bd6d782f6fc22549ddf1c2 Reviewed-on: https://go-review.googlesource.com/c/go/+/216697 Run-TryBot: Michael Knyszek <mknyszek@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com>