Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Hugh Dickins
On Tue, 2 Feb 2021, Axel Rasmussen wrote: > On Tue, Feb 2, 2021 at 1:03 PM Hugh Dickins wrote: > > On Tue, 2 Feb 2021, Axel Rasmussen wrote: > > > > > For background, mm/userfaultfd.c provides a general mcopy_atomic > > > implementation. But some types of memory (e.g., hugetlb and shmem) need > >

Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Mike Kravetz
On 2/2/21 12:31 PM, Axel Rasmussen wrote: > For background, mm/userfaultfd.c provides a general mcopy_atomic > implementation. But some types of memory (e.g., hugetlb and shmem) need > a slightly different implementation, so they provide their own helpers > for this. In other words, userfaultfd is

Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Axel Rasmussen
On Tue, Feb 2, 2021 at 1:03 PM Hugh Dickins wrote: > > On Tue, 2 Feb 2021, Axel Rasmussen wrote: > > > For background, mm/userfaultfd.c provides a general mcopy_atomic > > implementation. But some types of memory (e.g., hugetlb and shmem) need > > a slightly different implementation, so they

Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Hugh Dickins
On Tue, 2 Feb 2021, Axel Rasmussen wrote: > For background, mm/userfaultfd.c provides a general mcopy_atomic > implementation. But some types of memory (e.g., hugetlb and shmem) need > a slightly different implementation, so they provide their own helpers > for this. In other words, userfaultfd

Re: [PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Peter Xu
On Tue, Feb 02, 2021 at 12:31:27PM -0800, Axel Rasmussen wrote: > For background, mm/userfaultfd.c provides a general mcopy_atomic > implementation. But some types of memory (e.g., hugetlb and shmem) need > a slightly different implementation, so they provide their own helpers > for this. In other

[PATCH] userfaultfd: hugetlbfs: only compile UFFD helpers if config enabled

2021-02-02 Thread Axel Rasmussen
For background, mm/userfaultfd.c provides a general mcopy_atomic implementation. But some types of memory (e.g., hugetlb and shmem) need a slightly different implementation, so they provide their own helpers for this. In other words, userfaultfd is the only caller of this function. This patch