mem_map bitmaps ?
wu_yb (wu_yb@263.net)
Thu, 20 May 1999 20:50:45 +0800
I'm reading linux source code, and confused by bitmap size of mem_map.
In free_area_init() ( init.c , kernel 2.0.35 )
...
for ( i = 0; i < NR_MEM_LISTS; i++ ) {
unsigned long bitmap_size ;
init_mem_queue(free_area+i) ;
mask+=mask ;
end_mem = (end_mem + ~mask) &mask ;
bitmap_size = (end_mem - PAGE_OFFSET) >> (PAGE_SHIFT+i) ;
???????????????
bitmap_size = (bitmap_size+7) >> 3 ;
...
}
on bit of free_area[i].map represent 2^(i+1) pages, so I think the line
with ????
should be:
bitmap_size = (end_mem - PAGE_OFFSET ) >> (PAGE_SHIFT+i+1) ;
I know I would be error, but can anybody explain it to me, thanks very
much !!!!!
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