From: Michael Knyszek <mknyszek@google.com>
Date: Fri, 26 Apr 2019 15:53:44 +0000 (+0000)
Subject: Revert "runtime: scavenge memory upon allocating from scavenged memory"
X-Git-Tag: go1.12.5~8
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=fd3676302e8436ec9243ae0695582bbb3f31dc3a;p=gostls13.git

Revert "runtime: scavenge memory upon allocating from scavenged memory"

This reverts commit 8e093e7a1cd8a092f23717cb8f34bca489a3eee5
(CL 159500).

Reason for revert: Increases memory allocation latency in certain
situations.

Fixes #31679.

Change-Id: I15e02c53a58009fd907b619b8649de2cdeb29ef0
Reviewed-on: https://go-review.googlesource.com/c/go/+/174102
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Austin Clements <austin@google.com>
---

diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index 47e3a33391..6c0ea1bded 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -1198,16 +1198,6 @@ HaveSpan:
 		// heap_released since we already did so earlier.
 		sysUsed(unsafe.Pointer(s.base()), s.npages<<_PageShift)
 		s.scavenged = false
-
-		// Since we allocated out of a scavenged span, we just
-		// grew the RSS. Mitigate this by scavenging enough free
-		// space to make up for it.
-		//
-		// Also, scavengeLargest may cause coalescing, so prevent
-		// coalescing with s by temporarily changing its state.
-		s.state = mSpanManual
-		h.scavengeLargest(s.npages * pageSize)
-		s.state = mSpanFree
 	}
 	s.unusedsince = 0