I am sponsoring this FastTrack for Philippe Jung.
Requested binding is Patch, timeout 3/28/2008.
- Dan
Template Version: @(#)onepager.txt 1.31 07/08/08 SMI This information is
Copyright 2007 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name: new mdb stackinfo command
1.2. Name of Document Author/Supplier:
Philippe Jung
1.3. Date of This Document:
02/29/2008
1.4. Name of Major Document Customer(s)/Consumer(s):
1.4.1. The Community you expect to review your project:
1.4.2. The ARC(s) you expect to review your project:
PSARC
1.5. Email Aliases:
1.5.2. Responsible Engineer: Philippe.Jung at sun.com
1.5.4. Interest List:
Ken.Tomlinson at sun.com
Renaud.Manus at sun.com
William.Roche at sun.com
Chris.Beal at sun.com
2. Project Summary
2.1. Project Description:
Context: Some Solaris layered drivers (3rd parties) like EMC, Veritas
requests a change of Solaris default kernel stack size. This project
adds a new mdb command that helps to answer the following question:
"How close has this Solaris system be from a kernel stack overflow ?".
This project introduces a new mdb command (::stackinfo) and a new kernel
tunable (kmem_stackinfo).
At kernel thread creation time, the kernel thread stack is filled with
a specific pattern (instead of zero filled) if the kmem_stackinfo
variable
is set to non zero value. During the kernel thread execution, the kernel
thread stack pattern is progressively overwritten.
This feature takes in account hardware architecture (stack grows either
to
lower or larger addresses). A simple count from stack top until pattern
is
not found (or stack botom is reached) gives a high water mark value, the
maximum kernel stack space used by a kernel thread
This allows to compute the maximum usage (a high water mark) of kernel
stack
usage. This new mdb command (::stackinfo) can also display the 'dead'
kernel
threads that have exercised their kernel stack the most (a DTRACE
Statically
Defined Tracing probe is also provided for this).
Example:
/etc/system: set kmem_stackinfo=0x1
> ::stackinfo
THREAD STACK SIZE CUR MAX CMD/LWPID
000003000ec76a00 000002a10049a000 5ae0 3% 44% svc.startd/8
svc.startd/8 is currently at 3% of its kernel stack, but has already
used up to 44% of its kernel stack.
2.2. Risks and Assumptions:
None.
3. Business Summary
3.1. Problem Area:
Helps answering Solaris developers/system admins the following question:
"How close has this Solaris system be from a kernel stack overflow ?".
3.2. Market/Requester:
Any Solaris kernel developer (layered drivers), any Solaris system
administrator.
3.3. Business Justification:
3.4. Competitive Analysis:
N/A.
3.5. Opportunity Window/Exposure:
N/A.
3.6. How will you know when you are done?:
The project is already available. Project and code review has been
performed by following people:
Ken.Tomlinson at sun.com Renaud.Manus at sun.com William.Roche
at sun.com
Chris.Beal at sun.com
4. Technical Description:
4.1. Details:
file:///net/tb3.uk/tank/u/pjung/onnv_stack/web/stack.html
/net/tb3.uk/tank/u/pjung/onnv_stack/DOCS/STACKINFO.sxw
/net/tb3.uk/tank/u/pjung/onnv_stack/DOCS/STACKINFO.pdf
4.2. Bug/RFE Number(s):
6626918 A new (k)mdb command ::stackinfo, kernel thread stack usage
4.3. In Scope:
N/A.
4.4. Out of Scope:
N/A.
4.5. Interfaces:
A new tunable in /etc/system, like slab allocator debug kmem_flags.
set kmem_stackinfo = 0x1
A new (k)mdb command:
> ::help stackinfo
NAME
stackinfo - display kthread_t stack usage
SYNOPSIS
[ addr ] ::stackinfo
DESCRIPTION
-a show also TS_FREE kthreads
-h print history (dead kthreads)
ATTRIBUTES
Target: kvm
Module: genunix
Interface Stability: Unstable
A new Dtrace probe:
sdt:genunix:thread_log_stk_usage_free:stack-usage
4.6. Doc Impact:
None.
4.7. Admin/Config Impact:
None.
4.8. HA Impact:
None.
4.9. I18N/L10N Impact:
None.
4.10. Packaging & Delivery:
None (no new package or existing package modification).
4.11. Security Impact:
None.
4.12. Dependencies:
None.
5. Reference Documents:
file:///net/tb3.uk/tank/u/pjung/onnv_stack/web/stack.html
6. Resources and Schedule:
6.1. Projected Availability:
2 weeks
6.2. Cost of Effort:
development: 2 man/week (done)
QE:
QA:
6.4. Product Approval Committee requested information:
6.4.1. Consolidation or Component Name:
6.4.7. Target RTI Date/Release:
6.4.8. Target Code Design Review Date:
6.5. ARC review type:
// Standard
// SelfReview
6.6. ARC Exposure: open
6.6.1. Rationale: Part of OpenSolaris
7. Prototype Availability:
7.1. Prototype Availability:
file:///net/tb3.uk/tank/u/pjung/onnv_stack/webrev/index.html
/net/tb3.uk/tank/u/pjung/onnv_stack/DOCS/STACKINFO.sxw
/net/tb3.uk/tank/u/pjung/onnv_stack/DOCS/STACKINFO.pdf
7.2. Prototype Cost:
None (Prototype done).
