Re: [Crash-utility] improve ps performance

Upon a quick examination of the latest patchset posted, this will break pre-compiled extension modules that walk through the task list: --- a/crash-7.0.7/defs.h +++ b/crash-7.0.7/defs.h @@ -758,13 +758,23 @@ struct task_context { /* context stored for each task */ int processor; ulong ptask; ulong mm_struct; + ulong tgid; + ulong tgid_task_context_index; struct task_context *tc_next; }; Because it is typically done like so: struct task_context *tc; tc = FIRST_CONTEXT(); for (i = 0; i < RUNNING_TASKS(); i++, tc++) { ... Because it's an array, it's not safe to just move the new fields to the end of the data structure (as is the case with the program_context struct). Just checking the extension modules that are posted on the http://people.redhat.com/anderson web site, it would break 3 of them: $ grep RUNNING_TASKS *.c ksm.c: for (i = 0; i < RUNNING_TASKS(); i++, tc++) { swap_usage.c: for (i = 0; i < RUNNING_TASKS(); i++, tc++) { trace.c: for (i = 0; i < RUNNING_TASKS(); i++) trace.c: for (i = 0; i < RUNNING_TASKS(); i++) $ I haven't studied how this patchset works, but I wonder whether this could be avoided? It's not a set-in-stone rule that these kind of changes can never be made. But on the other hand, I don't believe that structure has ever been changed -- because anything about a task can be determined directly or indirectly from its contents. Dave ----- Original Message -----