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// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build debuglog
package runtime
const dlogEnabled = true
// dlogPerM is the per-M debug log data. This is embedded in the m
// struct.
type dlogPerM struct {
dlogCache *dlogger
}
// getCachedDlogger returns a cached dlogger if it can do so
// efficiently, or nil otherwise. The returned dlogger will be owned.
func getCachedDlogger() *dlogger {
mp := acquirem()
// We don't return a cached dlogger if we're running on the
// signal stack in case the signal arrived while in
// get/putCachedDlogger. (Too bad we don't have non-atomic
// exchange!)
var l *dlogger
if getg() != mp.gsignal {
l = mp.dlogCache
mp.dlogCache = nil
}
releasem(mp)
return l
}
// putCachedDlogger attempts to return l to the local cache. It
// returns false if this fails.
func putCachedDlogger(l *dlogger) bool {
mp := acquirem()
if getg() != mp.gsignal && mp.dlogCache == nil {
mp.dlogCache = l
releasem(mp)
return true
}
releasem(mp)
return false
}
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