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Re: [PATCH 2.6.9-rc2 2/2] enhanced MM accounting data collection

To: Jay Lan <jlan@xxxxxxxxxxxx>
Subject: Re: [PATCH 2.6.9-rc2 2/2] enhanced MM accounting data collection
From: Paul Jackson <pj@xxxxxxx>
Date: Tue, 28 Sep 2004 02:33:50 -0700
Cc: linux-kernel@xxxxxxxxxxxxxxx, lse-tech@xxxxxxxxxxxxxxxxxxxxx, csa@xxxxxxxxxxx, akpm@xxxxxxxx, guillaume.thouvenin@xxxxxxxx, tim@xxxxxxxxxxxxxxxxxxxxxx, corliss@xxxxxxxxxxxxxxxx
In-reply-to: <41589927.5080803@engr.sgi.com>
Organization: SGI
References: <4158956F.3030706@engr.sgi.com> <41589927.5080803@engr.sgi.com>
Sender: csa-bounce@xxxxxxxxxxx
nits:

1) I'm not sure the "no-op if CONFIG_CSA not set" comments
   are worthwhile - it does not seem to be a common practice
   to mark macros that collapse under certain CONFIG's with
   such comments, and some code, such as in fork.c, would
   become quite a bit less readable if such comments were
   widely used.

2) Three of the added csa_update_integrals() lines have
   leading spaces, instead of a tab char, such as in:

===================================================================
--- linux.orig/fs/exec.c        2004-09-27 11:57:40.201435722 -0700
+++ linux/fs/exec.c     2004-09-27 14:05:41.266160725 -0700
@@ -1163,6 +1164,9 @@
 
                /* execve success */
                security_bprm_free(&bprm);
+               /* no-op if CONFIG_CSA not set */
+                csa_update_integrals();                <=========
+                update_mem_hiwater();                  <=========
                return retval;
        }
 
3) Is it always the case that csa_update_integrals() and
   update_mem_hiwater() are used together?  If so, perhaps
   they could be collapsed into one?  Even the current->mm
   test inside them could be made one test, perhaps?

4) What kind of kernel text size expansion does this cause?
   There seem to be about a dozen of these calls.  What are
   the pros and cons of inlining csa_update_integrals() and
   update_mem_hiwater()?  Are these on hot enough kernel code
   paths that we should benchmark with and without these hooks
   enabled, both inline and out-of-line?

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj@xxxxxxx> 1.650.933.1373

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