I'm sponsoring this on behalf of Christopher Baumbauer. Exposure is
open, seeking patch binding. Timeout set for 04/03/2009.
- Dan
Template Version: @(#)onepager.txt 1.35 07/11/07 SMI
Copyright 2007 Sun Microsystems
Sun Proprietary/Confidential: Internal Use Only: Engineering Need-to-Know
1. Introduction
1.1. Project/Component Working Name:
Page Retirement Kernel KStat Addition
1.2. Name of Document Author/Supplier:
Author: Chris Baumbauer
1.3. Date of This Document:
03/16/2008
1.3.1. Date this project was conceived:
03/16/2008
1.4. Name of Major Document Customer(s)/Consumer(s):
1.4.1. The PAC or CPT you expect to review your project:
Solaris PAC
1.4.2. The ARC(s) you expect to review your project:
PSARC
1.4.3. The Director/VP who is "Sponsoring" this project:
brian.reynard at sun.com
1.4.4. The name of your business unit:
Solaris RPE Platform-Kernel
1.5. Email Aliases:
1.5.1. Responsible Manager: ken.yan at sun.com
1.5.2. Responsible Engineer: christopher.baumbauer at sun.com
1.5.3. Marketing Manager:
1.5.4. Interest List:
2. Project Summary
2.1. Project Description:
Provide a new kstat to indicate when a page of kernel memory is
slated for retirement.
2.2. Risks and Assumptions:
The addition of a new kstat may not get picked up by various debugging
and diagnostic tools.
3. Business Summary
3.1. Problem Area:
Customer experiences a nasty performance hit whenever the pagelock
cache is disabled, and in the case mentioned during the technical
description, the pagelock cache continuously gets disabled when
it shouldn't.
3.2. Market/Requester:
3.3. Business Justification:
3.4. Competitive Analysis:
3.5. Opportunity Window/Exposure:
3.6. How will you know when you are done?:
4. Technical Description:
4.1. Details:
The implementation is a part of a fix with page retirement where the
new kstat will be used to differentiate pages slated for retirement.
Since a kernel page will be locked throughout its lifetime, if it is
slated for retirement, the page will first find its way into a page
retirement pending queue (S10) or a page capture hash bucket (Nevada)
and then increment a kstat to indicate that a page is waiting to be
retired. Then a background thread (page_retire_thread in S10 or
page_capture_thread in Nevada) will check the pending kstat to see if
there is any work to do, go through the queue or hash, and attempt to
unlock the page in an effort to to induce a retirement. In the case
of kernel pages, they are always locked and will thus not undergo
retirement, but still force the page retirement thread to run and
attempt to cleanup the page while negatively impacting system
performance by unneccarily disabling the pagelock cache. Also, since
the kernel page has been marked for retirement, they will need to be
scrubbed on reboot to prevent possible future issues on the next boot.
Adding a new kstat that specifically tracks kernel pages placed
in the respective pending location will allow the page retirement
system to pull kernel pages out of circulation while still permit
their cleanup on reboot.
A kernel page retirement example:
# ./prt_sparc
Welcome to page_retire_test (PRT). 'h' for Help.
prt> M0x23f406000
ITER 0:
badpa 0
busy 0
again 1
not 0
ok 0
-----
prt> k
module: unix instance: 0
name: page_retire class: misc
crtime 73.371403096
pages_deferred 1
pages_deferred_kernel 0
pages_fma 0
pages_limit 514
pages_limit_exceeded 0
pages_multiple_ce 0
pages_notdequeued 0
pages_notenqueued 0
pages_pending 0
pages_pending_kas 1
pages_retire_request 0
pages_retire_request_free 0
pages_retired 0
pages_ue 0
pages_ue_cleared_freed 0
pages_ue_cleared_retired 0
pages_ue_persistent 0
pages_unretired 0
snaptime 302.701530127
prt> ^D
# mdb -k
Loading modules: [ unix genunix specfs dtrace ufs pcisch sd
ip hook neti sctp arp usba fctl nca lofs zfs cpc random
fcip ptm sppp nfs ]
> pr_pending_q::print
[ 0x70001fd0180, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ]
> 0x70001fd0180::print page_t
{
p_offset = 0x3000c406000
p_vnode = kvp
p_selock = 0
p_vpmref = 0
p_hash = 0
p_vpnext = 0x70001fd0100
p_vpprev = 0x70001fd0200
p_next = 0x70001fd0180
p_prev = 0x70001fd0180
p_lckcnt = 0x1
p_cowcnt = 0
p_cv = {
_opaque = 0
}
p_io_cv = {
_opaque = 0
}
p_iolock_state = 0
p_szc = 0x3
p_fsdata = 0
p_state = 0
p_nrm = 0
p_vcolor = 0x2
p_index = 0x8
p_toxic = 0x41
...
4.2. Bug/RFE Number(s):
CR 6587140
4.3. In Scope:
4.4. Out of Scope:
4.5. Interfaces:
New kstat variable (pr_pending_kas) which will be used in addition to
pr_pending to track the number of pages awaiting retirement.
4.6. Doc Impact:
4.7. Admin/Config Impact:
Programs and scripts that make use of the page_retirement kstats in
general, and the pr_pending kstat in particular.
4.8. HA Impact:
4.9. I18N/L10N Impact:
4.10. Packaging & Delivery:
4.11. Security Impact:
4.12. Dependencies:
5. Reference Documents:
CR 6587140
6. Resources and Schedule:
6.1. Projected Availability:
6.2. Cost of Effort:
6.3. Cost of Capital Resources:
6.4. Product Approval Committee requested information:
6.4.1. Consolidation or Component Name:
6.4.3. Type of CPT Review and Approval expected:
FastTrack
6.4.4. Project Boundary Conditions:
6.4.5. Is this a necessary project for OEM agreements:
no
6.4.6. Notes:
6.4.7. Target RTI Date/Release:
Nevada: snv_112
S10: S10u8_1
6.4.8. Target Code Design Review Date:
6.4.9. Update approval addition:
6.5. ARC review type:
Fasttrack
6.6. ARC Exposure:
open
6.6.1. Rationale:
7. Prototype Availability:
7.1. Prototype Availability:
7.2. Prototype Cost:
