On Tue, 25 Nov 2014 08:42:37 +0900 Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> wrote: > On Mon, Nov 24, 2014 at 02:55:42PM -0800, Andrew Morton wrote: > > On Mon, 24 Nov 2014 17:15:21 +0900 Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> wrote: > > > > > Now, we have prepared to avoid using debug-pagealloc in boottime. So > > > introduce new kernel-parameter to disable debug-pagealloc in boottime, > > > and makes related functions to be disabled in this case. > > > > > > Only non-intuitive part is change of guard page functions. Because > > > guard page is effective only if debug-pagealloc is enabled, turning off > > > according to debug-pagealloc is reasonable thing to do. > > > > > > ... > > > > > > --- a/Documentation/kernel-parameters.txt > > > +++ b/Documentation/kernel-parameters.txt > > > @@ -858,6 +858,14 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > > causing system reset or hang due to sending > > > INIT from AP to BSP. > > > > > > + disable_debug_pagealloc > > > + [KNL] When CONFIG_DEBUG_PAGEALLOC is set, this > > > + parameter allows user to disable it at boot time. > > > + With this parameter, we can avoid allocating huge > > > + chunk of memory for debug pagealloc and then > > > + the system will work mostly same with the kernel > > > + built without CONFIG_DEBUG_PAGEALLOC. > > > + > > > > Weren't we going to make this default to "off", require a boot option > > to turn debug_pagealloc on? > > Hello, Andrew. > > I'm afraid that changing default to "off" confuses some old users. > They would expect that it is default "on". But, it is just debug > feature, so, it may be no problem. If you prefer to change default, I > will rework this patch. Please let me know your decision. I suspect the number of "old users" is one ;) I think it would be better to default to off - that's the typical behaviour for debug features, for good reasons. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>