On Fri, Jan 13, 2012 at 10:35:42AM +0800, Huang Shijie wrote:
Hi,
I think simple patch is returning "return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE;"
It's very clear and readable, I think.
In this patch, what's the problem you think?
sorry for the wrong thread, please read the following thread:
http://marc.info/?l=linux-mm&m=132532266130861&w=2
Huang, Thanks for notice that thread.
I read and if I understand correctly, the point is that Mel want to see tracepoint
"trace_mm_compaction_migratepages" and account "count_vm_event(COMPACTBLOCKS);"
My patch does accounting COMPACTBLOCKS so it's not a problem.
Your patch also accounts the COMPACTBLOCKS In the ISOLATE_NONE and
ISOLATE_ABOART when :
++++++++++++++++++++++++++++++++++++++++++++++++++++++
/* Do not cross the free scanner or scan within a memory hole */
if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
cc->migrate_pfn = end_pfn;
return ISOLATE_NONE;
}
/*
* Ensure that there are not too many pages isolated from the LRU
* list by either parallel reclaimers or compaction. If there are,
* delay for some time until fewer pages are isolated
*/
while (unlikely(too_many_isolated(zone))) {
/* async migration should just abort */
if (!cc->sync)
return ISOLATE_ABORT;
congestion_wait(BLK_RW_ASYNC, HZ/10);
if (fatal_signal_pending(current))
return ISOLATE_ABORT;
}
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
this not make sense.
The problem is my patch doesn't emit trace of "trace_mm_compaction_migratepages".
But doesn't it matter? When we doesn't isolate any page at all, both argument in
trace_mm_compaction_migratepages are always zero. Is it meaningful tracepoint?
Do we really want it?
IMHO, yes.
For it _DOES_ scan one PAGEBLOCK even we can not get any page from this
pageblock.
it should trace the scan even the parameters are both zero.
Huang Shijie
Best Regards
Huang Shijie
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>