[CC Tejun] On Thu 03-08-17 14:38:22, Wei Yang wrote: > In pcpu_get_vm_areas(), it checks each range is not overlapped. To make > sure it is, only (N^2)/2 comparison is necessary, while current code does > N^2 times. By starting from the next range, it achieves the goal and the > continue could be removed. > > At the mean time, other two work in this patch: > * the overlap check of two ranges could be done with one clause > * one typo in comment is fixed. > > Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> > --- > mm/vmalloc.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 8087451cb332..f33c8350fd83 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2457,7 +2457,7 @@ static unsigned long pvm_determine_end(struct vmap_area **pnext, > * matching slot. While scanning, if any of the areas overlaps with > * existing vmap_area, the base address is pulled down to fit the > * area. Scanning is repeated till all the areas fit and then all > - * necessary data structres are inserted and the result is returned. > + * necessary data structures are inserted and the result is returned. > */ > struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, > const size_t *sizes, int nr_vms, > @@ -2485,15 +2485,11 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, > if (start > offsets[last_area]) > last_area = area; > > - for (area2 = 0; area2 < nr_vms; area2++) { > + for (area2 = area + 1; area2 < nr_vms; area2++) { > unsigned long start2 = offsets[area2]; > unsigned long end2 = start2 + sizes[area2]; > > - if (area2 == area) > - continue; > - > - BUG_ON(start2 >= start && start2 < end); > - BUG_ON(end2 <= end && end2 > start); > + BUG_ON(start2 < end && start < end2); > } > } > last_end = offsets[last_area] + sizes[last_area]; > -- > 2.11.0 > -- Michal Hocko SUSE Labs -- 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>