CVS commit: src/sys/kern

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Sat Oct 28 17:06:43 UTC 2017

Modified Files:
        src/sys/kern: subr_pool.c

Log Message:
Allow only one pending call to a pool's backing allocator at a time.

Candidate fix for problems with hanging after kva fragmentation related
to PR kern/45718.

Proposed on tech-kern:

https://mail-index.NetBSD.org/tech-kern/2017/10/23/msg022472.html

Tested by bouyer@ on i386.

This makes one small change to the semantics of pool_prime and
pool_setlowat: they may fail with EWOULDBLOCK instead of ENOMEM, if
there is a pending call to the backing allocator in another thread but
we are not actually out of memory.  That is unlikely because nearly
always these are used during initialization, when the pool is not in
use.

XXX pullup-8
XXX pullup-7
XXX pullup-6 (requires tweaking the patch)
XXX pullup-5...


To generate a diff of this commit:
cvs rdiff -u -r1.208 -r1.209 src/sys/kern/subr_pool.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.