Bug #11175: possible fibers memory leak or risky GC behavior

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN

[cvss (Kirill Vechera)]

There's strong memory growth on mass Fiber creation/deletion.

Script to demonstrate the problem (on x86_64-linux):

loop {
	10000.times.map { Fiber.new { } } 
	GC.start # not necessary, just to be sure
	puts File.open('/proc/self/status').grep(/VmRSS:/).first
}

Running this script shows RSS growing from 57 Mb to 1Gb within one minute. Than RSS remains in range from 850 Mb to 1200 Mb.

cv@new-cv:~/arena$ ruby fiber_memleak.rb
VmRSS:     57168 kB
VmRSS:    121668 kB
VmRSS:    183568 kB
...
VmRSS:   1114664 kB
VmRSS:   1122624 kB

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Feedback

I think this may be operating system/platform specific and could be fixed in a previous version. I could replicate the behavior on ruby 2.4.1p111 on x86_64-linux, but memory seemed to stablize around 180MB on ruby 2.7.0dev on i686-linux. Memory use stablized around 110-120MB on many versions of ruby on amd64-openbsd. Is anyone able to replicate this issue on the master branch on x86_64-linux?

[jeremyevans0 (Jeremy Evans)]

• Status changed from Feedback to Closed