From 29be3f1999d1ccf01110f4e1f2d628f54f6c65da Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Mon, 9 Jan 2017 11:35:42 -0500 Subject: runtime: generalize GC trigger Currently the GC triggering condition is an awkward combination of the gcMode (whether or not it's gcBackgroundMode) and a boolean "forceTrigger" flag. Replace this with a new gcTrigger type that represents the range of transition predicates we need. This has several advantages: 1. We can remove the awkward logic that affects the trigger behavior based on the gcMode. Now gcMode purely controls whether to run a STW GC or not and the gcTrigger controls whether this is a forced GC that cannot be consolidated with other GC cycles. 2. We can lift the time-based triggering logic in sysmon to just another type of GC trigger and move the logic to the trigger test. 3. This sets us up to have a cycle count-based trigger, which we'll use to make runtime.GC trigger concurrent GC with the desired consolidation properties. For #18216. Change-Id: If9cd49349579a548800f5022ae47b8128004bbfc Reviewed-on: https://go-review.googlesource.com/37516 Run-TryBot: Austin Clements TryBot-Result: Gobot Gobot Reviewed-by: Rick Hudson --- src/runtime/proc.go | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'src/runtime/proc.go') diff --git a/src/runtime/proc.go b/src/runtime/proc.go index ae19120a31..dae8f135bc 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -228,7 +228,8 @@ func forcegchelper() { if debug.gctrace > 0 { println("GC forced") } - gcStart(gcBackgroundMode, true) + // Time-triggered, fully concurrent. + gcStart(gcBackgroundMode, gcTrigger{kind: gcTriggerTime, now: nanotime()}) } } @@ -3790,8 +3791,7 @@ func sysmon() { idle++ } // check if we need to force a GC - lastgc := int64(atomic.Load64(&memstats.last_gc_nanotime)) - if gcShouldStart(true) && lastgc != 0 && now-lastgc > forcegcperiod && atomic.Load(&forcegc.idle) != 0 { + if t := (gcTrigger{kind: gcTriggerTime, now: now}); t.test() && atomic.Load(&forcegc.idle) != 0 { lock(&forcegc.lock) forcegc.idle = 0 forcegc.g.schedlink = 0 -- cgit v1.3