https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=248008
Bug ID: 248008
Summary: Post r358097 an i386 system can hang with many
processes sleeping on btalloc
Product: Base System
Version: CURRENT
Hardware: i386
OS: Any
Status: New
Severity: Affects Some People
Priority: ---
Component: kern
Assignee: b...@freebsd.org
Reporter: rmack...@freebsd.org
I think the patch is not complete. It looks like the problem is that
for systems that do not have UMA_MD_SMALL_ALLOC, we do
uma_zone_set_allocf(vmem_bt_zone, vmem_bt_alloc);
but we haven't set an appropriate free function. This is probably why
UMA_ZONE_NOFREE was originally there. When NOFREE was removed, it was
appropriate for systems with uma_small_alloc.
So by default we get page_free as our free function. That calls
kmem_free, which calls vmem_free ... but we do our allocs with
vmem_xalloc. I'm not positive, but I think the problem is that in
effect we vmem_xalloc -> vmem_free, not vmem_xfree.
Three possible fixes:
1: The one you tested, but this is not best for systems with
uma_small_alloc.
2: Pass UMA_ZONE_NOFREE conditional on UMA_MD_SMALL_ALLOC.
3: Actually provide an appropriate vmem_bt_free function.
I think we should just do option 2 with a comment, it's simple and it's
what we used to do. I'm not sure how much benefit we would see from
option 3, but it's more work.
--
You are receiving this mail because:
You are the assignee for the bug.
_______________________________________________
freebsd-bugs@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-bugs
To unsubscribe, send any mail to "freebsd-bugs-unsubscr...@freebsd.org"
