This is the mail archive of the systemtap@sourceware.org mailing list for the systemtap project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [RFC 0/3] Kprobes: support for userspace probes





The probe is inserted when the page is brough into memory, not in advance
of the system needing to load that page. This is done (or was done in the
original implementaiton) by hooking readpage. This also alows us to
register probes before the module is even loaded.
- -
Richard J Moore
IBM Advanced Linux Response Team - Linux Technology Centre
MOBEX: 264807; Mobile (+44) (0)7739-875237
Office: (+44) (0)1962-817072


                                                                           
             James Dickens                                                 
             <jamesd.wi@gmai                                               
             l.com>                                                     To 
             Sent by:                  prasanna@in.ibm.com                 
             systemtap-owner                                            cc 
             @sources.redhat           systemtap@sources.redhat.com        
             .com                                                      bcc 
                                                                           
                                                                   Subject 
             14/09/2005                Re: [RFC 0/3] Kprobes: support for  
             19:14                     userspace probes                    
                                                                           
                                                                           
             Please respond                                                
              to jamesd.wi                                                 
                                                                           
                                                                           




On 9/14/05, Prasanna S Panchamukhi <prasanna@in.ibm.com> wrote:
> Hi All,
>
> Please find the details of the userspace probes below.
> Also I have tried to implement the same to demonistrate
> this design, in 3 patches for linux kernel version 2.6.13.
>
> 1. Provides interface to insert probes when pages are in memory.
> 2. Adds a feature to insert probes on pages not present in the memory.

in the case where you probe a userland app, and its swapped out, then
memory pressure gets worse, and the code segment is discarded, thus
will be reloaded from disk next time. do you have a hook to tell the
monitoring software than they are no longer being probed? or do you
have a machanism that protects a block with probes in it from being
discarded?

James Dickens



>
> Prasanna S Panchamukhi
> Linux Technology Center
> India Software Labs, IBM Bangalore
> Ph: 91-80-25044636
> <prasanna@in.ibm.com>
>



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]