Russell King - ARM Linux wrote on Thursday, August 25, 2011 3:53 PM: > On Thu, Aug 25, 2011 at 09:35:07AM +0530, Pedanekar, Hemant wrote: >> E.g., on OMAP3 with mem=32M@0x80000000 mem=8M@0x87800000 >> >> (CASE 1) >> Memory: 32MB 8MB = 40MB total >> Memory: 28408k/28408k available, 12552k reserved, 0K highmem >> Virtual kernel memory layout: >> vector : 0xffff0000 - 0xffff1000 ( 4 kB) >> fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB) >> DMA : 0xffc00000 - 0xffe00000 ( 2 MB) >> vmalloc : 0xc8800000 - 0xf8000000 ( 760 MB) >> lowmem : 0xc0000000 - 0xc8000000 ( 128 MB) >> modules : 0xbf000000 - 0xc0000000 ( 16 MB) >> .text : 0xc0008000 - 0xc05ac2c8 (5777 kB) >> .init : 0xc05ad000 - 0xc05f8780 ( 302 kB) >> .data : 0xc05fa000 - 0xc06838d0 ( 551 kB) >> .bss : 0xc06838f4 - 0xc0bd8a14 (5461 kB) >> >> Is this expected? 88MB space between two 'mem's seems to have lost. > > Yes. The memory layout lines gives an overview of the virtual memory > address space _regions_. > > What it's saying is that the virtual addresses from 0xc0000000 - 0xc8000000 > are used for lowmem. That may not be fully populated, but that's what > the address range is reserved for. > So, larger the hole, more address space will be unusable - is that correct? >> This also >> means vmalloc space is lower compared to when a single mem=40M is passed. > > Huh. Either your maths is wrong or... > > Here's case 1: >> vmalloc : 0xc8800000 - 0xf8000000 ( 760 MB) And case 2: >> vmalloc : 0xc3000000 - 0xf8000000 ( 848 MB) > > Looks to me like case 1, vmalloc space is _higher_ not _lower_. That's > expected because you told the kernel it had more memory in case 1. Sorry, my mistake - I actually meant "vmalloc space is _smaller_ compared to when a single mem=40M is passed" though the actual physical RAM available is same in both the cases. Thanks. Hemant-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
