Messages in this thread | | | Date | Thu, 31 Jul 2014 15:45:40 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR |
| |
On Thu, 31 Jul 2014 14:58:58 +0530 Chintan Pandya <cpandya@codeaurora.org> wrote:
> > > > I think Andrew's comment earlier was referring to the changelog only and > > not the patch, which looked correct. > > I think Andrew asked for a BUG case details also to justify the > overhead. But we have never encountered that BUG case. Present patch is > only logical fix to the code. However, in the fast path, if such > overhead is allowed, I can move BUG_ON out of any debug configs. > Otherwise, as per Andrew's suggestion, I will convert DEBUG_HIGHMEM into > DEBUG_VM which is used more frequently.
The v1 patch added a small amount of overhead to kmap_atomic() for what is evidently a very small benefit.
Yes, I suggest we remove CONFIG_DEBUG_HIGHMEM from the kernel entirely and switch all CONFIG_DEBUG_HIGHMEM sites to use CONFIG_DEBUG_VM. That way the BUG_ON which you believe is useful will be tested by more people more often.
| |