builder: use proper percentage calculations for default gc policy

jsternberg · thaJeztah · commit dccf7c889c88 · 2025-10-07T19:10:14.000+02:00
The default gc policy calculations based on percentage were calculated improperly. These were calculated correctly in buildkit, but the calculation method was not copied over correctly when updating the values. Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com> (cherry picked from commit 1a7d7cc) Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
diff --git a/builder/builder-next/worker/gc.go b/builder/builder-next/worker/gc.go
@@ -72,6 +72,6 @@ func DefaultGCPolicy(p string, reservedSpace, maxUsedSpace, minFreeSpace int64)
 }
 
 func diskPercentage(dstat disk.DiskStat, percentage int64) int64 {
-	avail := dstat.Total / percentage
+	avail := dstat.Total * percentage / 100
 	return (avail/(1<<30) + 1) * 1e9 // round up
 }

Original file line number	Diff line number	Diff line change
`@@ -72,6 +72,6 @@ func DefaultGCPolicy(p string, reservedSpace, maxUsedSpace, minFreeSpace int64)`
`72`	`72`	`}`
`73`	`73`
`74`	`74`	`func diskPercentage(dstat disk.DiskStat, percentage int64) int64 {`
`75`		`- avail := dstat.Total / percentage`
	`75`	`+ avail := dstat.Total * percentage / 100`
`76`	`76`	`return (avail/(1<<30) + 1) * 1e9 // round up`
`77`	`77`	`}`