[Crash-utility] Thoughts on swap_usage Crash extension?

Dave Anderson anderson at redhat.com
Wed Feb 6 16:17:51 UTC 2013



----- Original Message -----
> Hi Dave,
> 
> Thanks for your suggestions.
> The latest version is here [1].
> 
> Cheers,
> Aaron

Hi Aaron,

Looks good -- I've copied it to the extensions page, with this one
minor (pedantic) change:


--- swap_usage.c.git	2013-02-06 11:13:24.894266556 -0500
+++ swap_usage.c	2013-02-06 11:04:22.770286178 -0500
@@ -229,7 +229,7 @@
 	"  If no arguments are specified, every user process will be checked.",
 	"  Supported on ARM, X86, X86_64, ALPHA, IA64 and S390 only.",
 	"\nEXAMPLE",
-	"    Show the swap consumption for pid 1232, 1353 and 2275:\n",
+	"  Show the swap consumption for pid 1232, 1353 and 2275:\n",
 	"    crash> pswap 1232 1353 2275",
 	"    PID     SWAP     COMM",
 	"     1232     34    auditd",

Thanks!
  Dave


> 
> [1]:
> https://github.com/aktlin115/crash-extension/blob/master/swap_usage.c
> 
> ----- Original Message -----
> From: "Dave Anderson" <anderson at redhat.com>
> To: "Discussion list for crash utility usage, maintenance and
> development" <crash-utility at redhat.com>
> Sent: Monday, February 4, 2013 8:13:29 PM
> Subject: Re: [Crash-utility] Thoughts on swap_usage Crash extension?
> 
> 
> 
> ----- Original Message -----
> > Hi Dave, Bryn,
> > 
> > I've made some changes (see the attachments) to support the
> > following:
> > 
> > 	ARM, X86, X86_64, ALPHA, IA64 and S390
> > 
> > Unfortunately these are the only definitions I could find at the
> > moment.
> > As per your suggestion, the command name has been changed to
> > "pswap" which
> > is more appropriate and the extension displays the swap count in
> > pages by default.
> > The '-k' option is added to display in kilobytes.
> > 
> > The latest version is here [1].
> > 
> > Cheers,
> > 
> > Aaron
> 
> Hi Aaron,
> 
> Looks good, architecture-restrictions notwithstanding.  With respect
> to
> the -k option, maybe it would be helpful to add a "k" to the end of
> the
> number, similar to the way it's done by the swap command?
> 
>  crash> swap
>  FILENAME           TYPE         SIZE      USED   PCT  PRIORITY
>  /dev/dm-0        PARTITION    9994236k   30980k   0%     0
>  crash>
> 
> The only other suggestion would be to make the help page a bit more
> consistent with the other help pages:
> 
>  crash> help pswap
> 
>  NAME
>    pswap - Returns the actual swap consumption of a user process
> 
>  SYNOPSIS
>    pswap [-k] [pid | taskp]
> 
>  DESCRIPTION
>    This command obtains the swap consumption (in pages) of a user
>    process.
>    The -k option can be used to print in kilobytes.  Supported on
>    ARM, X86, X86_64, ALPHA, IA64 and S390 only.
> 
>  EXAMPLE
>      Show the swap consumption for pid 1288, 1232 and 663:
> 
>          crash> pswap 1288 1232 663
>          PID     SWAP     COMM
>           1288   2100    audispd
>           1232    188    bluetoothd
>            663   3384    udevd
>          crash>
>  
>  If no arguments are specified, every user process will be checked.
> 
>  crash>
> 
> so that:
> 
>  (1) all lines are 80 columns or less,
>  (2) the "If not arguments are specified..." line is moved up into
>  the DESCRIPTION section.
>  (3) the EXAMPLE text is moved to the left, i,e., similar to other
>  help page examples.
> 
> I've copied this latest version to the extensions page.
> 
> Thanks,
>   Dave
> 
> > ---
> > [1]:
> > https://github.com/aktlin115/crash-extension/blob/master/swap_usage.c
> > 
> > ----- Original Message -----
> > From: "Dave Anderson" <anderson at redhat.com>
> > To: "Discussion list for crash utility usage, maintenance and
> > development" <crash-utility at redhat.com>
> > Sent: Wednesday, January 30, 2013 2:41:21 PM
> > Subject: Re: [Crash-utility] Thoughts on swap_usage Crash
> > extension?
> > 
> > 
> > Aaron,
> > 
> > Bryn's name change and pte_file() suggestion make good sense.
> > 
> > I also wonder if it's worth adding an option to alternatively
> > display
> > the swap count in pages?  The only crash commands I can think of
> > off-hand that use kilobytes are the "ps" and "swap" commands, and
> > those were done that way because of the Linux commands of the same
> > name.  But when I want to see how much swap a process is using I
> > do this to get a page count:
> > 
> >  crash> vm -p 1 | grep SWAP | wc -l
> >  382
> >  crash>
> > 
> > Or maybe just show both all the time?  Just a thought...
> > 
> > In any case, I've put the module in the crash extensions page as-is
> > for now.  When you're ready to update it, I'll just plug in your
> > latest-and-greatest version.
> > 
> >   http://people.redhat.com/anderson/extensions.html
> > 
> > Thanks,
> >   Dave
> > 
> > ----- Original Message -----
> > > Hi Bryn,
> > > 
> > > Thanks for the feedback.
> > > I'll work on it. With regards to the name change, I think it's
> > > worth
> > > changing it to 'pswap'.
> > > 
> > > Cheers,
> > > Aaron
> > > 
> > > ----- Original Message -----
> > > From: "Bryn M. Reeves" <bmr at redhat.com>
> > > To: "Discussion list for crash utility usage, maintenance and
> > > development" <crash-utility at redhat.com>
> > > Cc: "Aaron Tomlin" <atomlin at redhat.com>
> > > Sent: Wednesday, January 30, 2013 1:51:35 PM
> > > Subject: Re: [Crash-utility] Thoughts on swap_usage Crash
> > > extension?
> > > 
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > > 
> > > On 01/30/2013 01:17 PM, Aaron Tomlin wrote:
> > > > I've made some changes [1] and included the help page, as per
> > > > your
> > > > request. It's still x86_64 specific for now. What do you think?
> > > > [1]:
> > > > https://github.com/aktlin115/crash-extension/blob/master/swap_usage.c
> > > 
> > > Hi
> > > > 
> > > Aaron,
> > > 
> > > Extension looks useful. I was wondering about the name - would
> > > you
> > > consider renaming it as 'pswap'? It's less to type than
> > > swap_usage
> > > (as
> > > there's already a 'swap' command but nothing 'psw*').
> > > 
> > > For the _PAGE_FILE problem it might be possible to address this
> > > by
> > > providing a wrapper like the pte_file() interface defined by arch
> > > headers in the kernel sources.
> > > 
> > > There seem to be 11 arches (inc. x86 and powerpc) using
> > > (pte_val(pte)
> > > & _PAGE_FILE) idiom. Of the rest s390 has a well-commented
> > > explanation
> > > of its special cases and ARM uses a different name for the bit:
> > > 
> > > #define pte_file(pte)		(pte_val(pte) & L_PTE_FILE)
> > > 
> > > It seems like these could all be handled quite reasonably
> > > (actually
> > > the number that are identical maybe it's the case that this could
> > > be
> > > tidied up in the kernel so that arches that really need custom
> > > versions can override pte_file() but that's not really my area).
> > > 
> > > Regards,
> > > Bryn.
> > > -----BEGIN PGP SIGNATURE-----
> > > Version: GnuPG v1.4.12 (GNU/Linux)
> > > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
> > > 
> > > iEYEARECAAYFAlEJJWcACgkQ6YSQoMYUY97PKwCfa6ZuC2MuTrYa2E42WSEkBPjM
> > > 234An1RQFlRxrDFgMu/cxdhEMzfsRGGZ
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> > > 
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> > > 
> > 
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