was not anymore/yet on the freelist and uvm_fpageqlock was not held
-clear PQ_FREE while the page is in the works of pageidlezero
This avoids that the DMA memory allocator (pglistalloc) grabs a page
which is not on the freelist, leading to a diagnostic panic (with DEBUG)
or freelist corruption. (mostly on X server activation after a VT
switch or suspend/resume because this can allocate megabytes of AGP
memory)
This might fix PR port-i386/38989 by Alan Barrett (in case this was
a multiprocessor).
serves as less of a barrier these days. Restrict provision of kernel reserve
pages to kmem and one of these cases:
- doing a NOWAIT allocation
- caller is a realtime thread
- caller is a kernel thread
- explicitly requested, for example by the pmap
use both types of list.
- Make page coloring and idle zero state per-CPU.
- Maintain per-CPU page freelists. When freeing, put pages onto the local
CPU's lists and the global lists. When allocating, prefer to take pages
from the local CPU. If none are available take from the global list as
done now. Proposed on tech-kern@.
- Use high and low water marks to try and reduce power consumption.
- Do trylock on uvm_fpageqlock, and bail if we can't get it.
- Only run on one CPU at a time.
from doc/BRANCHES:
idle lwp, and some changes depending on it.
1. separate context switching and thread scheduling.
(cf. gmcgarry_ctxsw)
2. implement idle lwp.
3. clean up related MD/MI interfaces.
4. make scheduler(s) modular.
- finish implementing splraiseipl (and makeiplcookie).
http://mail-index.NetBSD.org/tech-kern/2006/07/01/0000.html
- complete workqueue(9) and fix its ipl problem, which is reported
to cause audio skipping.
- fix netbt (at least compilation problems) for some ports.
- fix PR/33218.
- don't use managed mappings/backing objects for wired memory allocations.
save some resources like pv_entry. also fix (most of) PR/27030.
- simplify kernel memory management API.
- simplify pmap bootstrap of some ports.
- some related cleanups.
- decrement uvmexp.anonpages as it's no longer an anon page.
- null out anon->u.an_page as the anon no longer own the page.
uvm_anfree: add related assertions.
insert the replacement page into the same position
as the original page on the object memq so that
genfs_putpages (and lfs) won't be confused.
noted by Stephan Uphoff (PR/24328)
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