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() - ... > + * 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 > + * 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 :) > + * > + * @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. -- Thanks, David / dhildenb
