| Message ID | 20210323074831.GA7535@kryton.kat.ac.za (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Clarify that MAP_POPULATE is best-effort | expand |
Hello Bruce, On 3/23/21 8:48 AM, Bruce Merry wrote: > As discussed on linux-mm > (https://marc.info/?l=linux-mm&m=161528594100612&w=2), MAP_POPULATE can > fail silently if the hugetlb cgroup settings allow huge page reservation > but prevents huge pages being allocated. > > Closes https://bugzilla.kernel.org/show_bug.cgi?id=212153. > --- > man2/mmap.2 | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/man2/mmap.2 b/man2/mmap.2 > index 164ba196e..03f2eeb2c 100644 > --- a/man2/mmap.2 > +++ b/man2/mmap.2 > @@ -400,6 +400,11 @@ private writable mappings. > Populate (prefault) page tables for a mapping. > For a file mapping, this causes read-ahead on the file. > This will help to reduce blocking on page faults later. > +The > +.BR mmap () > +call doesn't fail if the mapping cannot be populated (for example, due > +to limitations on the number of mapped huge pages when using > +.BR MAP_HUGETLB ). > .BR MAP_POPULATE > is supported for private mappings only since Linux 2.6.23. > .TP Thanks. Patch applied. Cheers, Michael
diff --git a/man2/mmap.2 b/man2/mmap.2 index 164ba196e..03f2eeb2c 100644 --- a/man2/mmap.2 +++ b/man2/mmap.2 @@ -400,6 +400,11 @@ private writable mappings. Populate (prefault) page tables for a mapping. For a file mapping, this causes read-ahead on the file. This will help to reduce blocking on page faults later. +The +.BR mmap () +call doesn't fail if the mapping cannot be populated (for example, due +to limitations on the number of mapped huge pages when using +.BR MAP_HUGETLB ). .BR MAP_POPULATE is supported for private mappings only since Linux 2.6.23. .TP