* David Hildenbrand <david@xxxxxxxxxx> [220623 13:26]: > On 21.06.22 22:46, Liam Howlett wrote: > > From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> > > > > The maple tree code was added to find the unmapped area in a previous > > commit and was checked against what the rbtree returned, but the actual > > result was never used. Start using the maple tree implementation and > > remove the rbtree code. > > > > Add kernel documentation comment for these functions. > > > > Link: https://lkml.kernel.org/r/20220504010716.661115-15-Liam.Howlett@xxxxxxxxxx > > Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx> > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: David Howells <dhowells@xxxxxxxxxx> > > Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > > Cc: SeongJae Park <sj@xxxxxxxxxx> > > Cc: Vlastimil Babka <vbabka@xxxxxxx> > > Cc: Will Deacon <will@xxxxxxxxxx> > > Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx> > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > --- > > mm/mmap.c | 253 +++++++----------------------------------------------- > > 1 file changed, 32 insertions(+), 221 deletions(-) > > > > diff --git a/mm/mmap.c b/mm/mmap.c > > index 08845a0317bf..b91d22329418 100644 > > --- a/mm/mmap.c > > +++ b/mm/mmap.c > > @@ -2053,250 +2053,61 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > > return error; > > } > > > > +/* unmapped_area() Find an area between the low_limit and the high_limit with > > /** > * unmapped_area() - ... ack. > > > + * the correct alignment and offset, all from @info. Note: current->mm is used > > + * for the search. > > + * > > + * @info: The unmapped area information including the range (low_limit - > > + * hight_limit), the alignment offset and mask. > > + * > > + * Return: A memory address or -ENOMEM. > > + */ > > static unsigned long unmapped_area(struct vm_unmapped_area_info *info) > > { > > ... > > > > > +/* unmapped_area_topdown() Find an area between the low_limit and the > > \Dito ack. > > > + * high_limit with * the correct alignment and offset at the highest available > > + * address, all from * @info. Note: current->mm is used for the search. > > I'm confused about the "*" in the text, but maybe I'm just tired :) So was my auto-formatting, I guess. I'll fix this. > > > + * > > + * @info: The unmapped area information including the range (low_limit - > > + * hight_limit), the alignment offset and mask. > > + * > > + * Return: A memory address or -ENOMEM. > > + */ > > static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) > > { > > [...] > > > -found: > > - /* We found a suitable gap. Clip it with the original high_limit. */ > > - if (gap_end > info->high_limit) > > - gap_end = info->high_limit; > > - > > -found_highest: > > - /* Compute highest gap address at the desired alignment */ > > - gap_end -= info->length; > > - gap_end -= (gap_end - info->align_offset) & info->align_mask; > > - > > - VM_BUG_ON(gap_end < info->low_limit); > > - VM_BUG_ON(gap_end < gap_start); > > Can we leave some of these in, please? (same applies to other function) > > I keep getting confused by align_offset. vs align_mask. I *think* this > is correct, but some checks that we stay in limits and actually have > proper alignment would be reasonable. Right, so in the version that existed with both rbtree and maple tree had a BUG_ON if my calculation wasn't the same as the rbtree calculation. I'll re-add the VM_BUG_ON() statements as you suggest for good measure. Thanks, Liam > > > -- > Thanks, > > David / dhildenb >
