On Wed, 20 Apr 2022 16:40:39 +0800 lipeifeng@xxxxxxxx wrote: > The old method will firstly find the space in len(info->length > + info->align_mask), and get address at the desired alignment. > > Sometime, addr would be failed if there are enough > addr space in kernel by above method, e.g., you can't get a > addr sized in 1Mbytes, align_mask 1Mbytes successfully although > there are still (2M-1)bytes space in kernel. > > This patch would fix thr problem above by the new method: find the > space in info->length and judge if at the desired info->align_mask > at the same time. > > Do a simple test in TIF_32BIT with unmapped_area: > - Try to take addr (size:1M align:2M) until allocation fails; > - Try to take addr (size:1M align:1M) and account how to space can > be alloced successfully. > > Before optimization: alloced 0 bytes. > After optimization: alloced 1.9+G bytes. Thanks. Unfortunately this part of the code is undergoing a lot of change lately. How serious is this problem? Please tell us how often the problem is being observed, under what circumstances, etc.
