Hi Tejun, On Mon, Sep 09, 2013 at 09:58:15AM -0400, Tejun Heo wrote: >Hello, > >On Mon, Sep 09, 2013 at 07:56:34PM +0800, Wanpeng Li wrote: >> If allocate from low to high as what this patchset done will occupy the >> precious memory you mentioned? > >Yeah, and that'd be the reason why this behavior is dependent on a >kernel option. That said, allocating some megs on top of kernel isn't >a big deal. The wretched ISA DMA is mostly gone now and some megs >isn't gonna hurt 32bit DMAs in any noticeable way. I wouldn't be too >surprised if nobody notices after switching the default behavior to >allocate early mem close to kernel. Maybe the only case which might >be impacted is 32bit highmem configs, but they're messed up no matter >what anyway and even they shouldn't be affected noticeably if large >mapping is in use. ISA DMA is still survive for 32bit highmem configs. In my desktop: c1000000 T _text => 16MB c1d09000 B _end => 29MB This patchset will alloc after 29MB. ;-) Regards, Wanpeng Li > >Thanks. > >-- >tejun -- 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>