Re: [PATCH] mm/mmap: fix the adjusted length error

2019-07-12 Thread Michel Lespinasse
Andrew Morton [mailto:a...@linux-foundation.org] > Sent: Friday, July 12, 2019 9:20 AM > To: chenjianhong (A) > Cc: Michel Lespinasse ; Greg Kroah-Hartman > ; mho...@suse.com; Vlastimil Babka > ; Kirill A. Shutemov ; Yang > Shi ; ja...@google.com; steve.cap...@arm.com; > tiny.

RE: [PATCH] mm/mmap: fix the adjusted length error

2019-07-12 Thread chenjianhong (A)
ux-mm ; sta...@vger.kernel.org; wi...@infradead.org Subject: Re: [PATCH] mm/mmap: fix the adjusted length error On Sat, 18 May 2019 07:05:07 + "chenjianhong (A)" wrote: > I explain my test code and the problem in detail. This problem is > found in 32-bit user process, because its

Re: [PATCH] mm/mmap: fix the adjusted length error

2019-07-11 Thread Andrew Morton
On Sat, 18 May 2019 07:05:07 + "chenjianhong (A)" wrote: > I explain my test code and the problem in detail. This problem is found in > 32-bit user process, because its virtual is limited, 3G or 4G. > > First, I explain the bug I found. Function unmapped_area and >

RE: [PATCH] mm/mmap: fix the adjusted length error

2019-05-18 Thread chenjianhong (A)
return ret; } -Original Message- From: Michel Lespinasse [mailto:wal...@google.com] Sent: Saturday, May 18, 2019 8:13 AM To: chenjianhong (A) Cc: Greg Kroah-Hartman ; Andrew Morton ; mho...@suse.com; Vlastimil Babka ; Kirill A. Shutemov ; Yang Shi ; ja...@google.com; steve.cap...

Re: [PATCH] mm/mmap: fix the adjusted length error

2019-05-17 Thread Michel Lespinasse
I worry that the proposed change turns the search from an O(log N) worst case into a O(N) one. To see why the current search is O(log N), it is easiest to start by imagining a simplified search algorithm that wouldn't include the low and high address limits. In that algorithm, backtracking