On Mon, Jan 25, 2016 at 08:51:56PM +0100, Christian Borntraeger wrote: > On 01/25/2016 08:38 PM, Dave Jones wrote: > > Content preview: On Mon, Jan 25, 2016 at 02:22:10PM -0500, Dave Jones > > wrote: > > > > A default mode would be ok for me as it makes things obvious. Will > > send > > > > a patch. > > The messaging around changing a default like this was > > really > > poor. > When we do behaviour changes like this, we typically rename the > > CONFIG > > option > to make it obvious that things aren't as they used to be. > > [...] > > > > Content analysis details: (-2.9 points, 5.0 required) > > > > pts rule name description > > ---- ---------------------- > > -------------------------------------------------- > > -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP > > -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% > > [score: 0.0000] > > X-ZLA-Header: unknown; 0 > > X-ZLA-DetailInfo: BA=6.00004114; NDR=6.00000001; ZLA=6.00000005; > > ZF=6.00000009; ZB=6.00000000; ZH=6.00000000; ZP=6.00000000; ZU=6.00000002; > > UDB=6.00294159; UTC=2016-01-25 19:38:24 > > x-cbid: 16012519-0041-0000-0000-0000074865D5 > > X-IBM-ISS-SpamDetectors: Score=0.40962; FLB=0; FLI=0; BY=0; FL=0; FP=0; > > FZ=0; > > HX=0; KW=0; PH=0; RB=0; SC=0.40962; ST=0; TS=0; UL=0; ISC= > > X-IBM-ISS-DetailInfo: BY=3.00004831; HX=3.00000240; KW=3.00000007; > > PH=3.00000004; SC=3.00000137; SDB=6.00650474; UDB=6.00294159; > > UTC=2016-01-25 > > 19:38:24 > > X-TM-AS-MML: disable > > > > On Mon, Jan 25, 2016 at 02:22:10PM -0500, Dave Jones wrote: > > > > > > A default mode would be ok for me as it makes things obvious. Will > > send > > > > a patch. > > > > > > The messaging around changing a default like this was really poor. > > > When we do behaviour changes like this, we typically rename the CONFIG > > option > > > to make it obvious that things aren't as they used to be. > > > > Looking at this closer, shouldn't the original diff to make this runtime > > have also changed the x86 implementation details in arch/x86/mm/pageattr.c ? > > Even when we don't boot with the enable flag, we're doing the "split 2M > > page into 4Ks" > > thing. It looks like a s/debug_pagealloc/debug_pagealloc_enabled()/ might > > do the right thing maybe ? > > I have some patches ready, that fix the identity mapping for s390 and x86. > sparc > is hard to do as it allocates the TSB very early. Will send around what I > have soon.
Thanks for taking care of this. I searched other sites using "#ifdef CONFIG_DEBUG_PAGEALLOC" and found that we can do more. Maybe, powerpc and tile also can get benefit from such a change. And, could you handle vmap_debug_free_range() and get_freepointer_safe(), too? And, when debug_pagealloc is disabled, it's better not to print DEBUG_PAGEALLOC in some error logs. Thanks.
