| Message ID | 20220531011157.46868-3-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | userfaultfd.2: Update to latest | expand |
Hi Peter, On 5/31/22 03:11, Peter Xu wrote: > The shmem/hugetlbfs memory types are supported for write-protection > messages very lately. Update the man page to reflect that. > > Signed-off-by: Peter Xu <peterx@redhat.com> Please see some source formatting comments below. Cheers, Alex > --- > man2/userfaultfd.2 | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 > index 0928a76d2..99aae8b50 100644 > --- a/man2/userfaultfd.2 > +++ b/man2/userfaultfd.2 > @@ -273,13 +273,17 @@ Since Linux 4.11, > userfaultfd can be also used with hugetlbfs and shared memory mappings. > .\" > .SS Userfaultfd write-protect mode (since 5.7) > -Since Linux 5.7, userfaultfd supports write-protect mode. > +Since Linux 5.7, userfaultfd supports write-protect mode for anonymous memory. > The user needs to first check availability of this feature using > .B UFFDIO_API > ioctl against the feature bit > .B UFFD_FEATURE_PAGEFAULT_FLAG_WP > before using this feature. > .PP > +Since Linux 5.19, the write-protection mode was also supported on shmem and hugetlbfs > +memory types. It can be detected with the feature bit See man-pages(7): [ Use semantic newlines In the source of a manual page, new sentences should be started on new lines, and long sentences should be split into lines at clause breaks (commas, semicolons, colons, and so on). This convention, sometimes known as "seman‐ tic newlines", makes it easier to see the effect of patches, which often operate at the level of individual sentences or sentence clauses. ] > +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM . > +.PP > To register with userfaultfd write-protect mode, the user needs to initiate the > .B UFFDIO_REGISTER > ioctl with mode > @@ -330,8 +334,6 @@ ioctl, whose > should have the flag > .B UFFDIO_WRITEPROTECT_MODE_WP > cleared upon the faulted page or range. > -.PP > -Write-protect mode supports only private anonymous memory. > .SS Reading from the userfaultfd structure > Each > .BR read (2)
diff --git a/man2/userfaultfd.2 b/man2/userfaultfd.2 index 0928a76d2..99aae8b50 100644 --- a/man2/userfaultfd.2 +++ b/man2/userfaultfd.2 @@ -273,13 +273,17 @@ Since Linux 4.11, userfaultfd can be also used with hugetlbfs and shared memory mappings. .\" .SS Userfaultfd write-protect mode (since 5.7) -Since Linux 5.7, userfaultfd supports write-protect mode. +Since Linux 5.7, userfaultfd supports write-protect mode for anonymous memory. The user needs to first check availability of this feature using .B UFFDIO_API ioctl against the feature bit .B UFFD_FEATURE_PAGEFAULT_FLAG_WP before using this feature. .PP +Since Linux 5.19, the write-protection mode was also supported on shmem and hugetlbfs +memory types. It can be detected with the feature bit +.BR UFFD_FEATURE_WP_HUGETLBFS_SHMEM . +.PP To register with userfaultfd write-protect mode, the user needs to initiate the .B UFFDIO_REGISTER ioctl with mode @@ -330,8 +334,6 @@ ioctl, whose should have the flag .B UFFDIO_WRITEPROTECT_MODE_WP cleared upon the faulted page or range. -.PP -Write-protect mode supports only private anonymous memory. .SS Reading from the userfaultfd structure Each .BR read (2)
The shmem/hugetlbfs memory types are supported for write-protection messages very lately. Update the man page to reflect that. Signed-off-by: Peter Xu <peterx@redhat.com> --- man2/userfaultfd.2 | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)