| Message ID | 20241008132440.722309-7-adhemerval.zanella@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | Updates for Linux 6.11 | expand |
On Okt 08 2024, Adhemerval Zanella wrote: > +@item MAP_DROPPABLE > +This request the page to be never written out to swap, it will be zeroed Remove "This". > +under memory pressure (so kernel can just drop the page), it is inherited > +by fork, it is not counted against @code{mlock} budget, and if there is > +no enough memory to service a page faults there is no fatal error (so not no -> not, faults -> fault, not -> no > +signal is sent).
diff --git a/manual/llio.texi b/manual/llio.texi index a035c3e20f..c8e6e07ea0 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1762,6 +1762,15 @@ write dirty metadata out whenever dirty data is written out. Unlike most other flags, this one will fail unless @code{MAP_SHARED_VALIDATE} is also given. +@item MAP_DROPPABLE +This request the page to be never written out to swap, it will be zeroed +under memory pressure (so kernel can just drop the page), it is inherited +by fork, it is not counted against @code{mlock} budget, and if there is +no enough memory to service a page faults there is no fatal error (so not +signal is sent). + +The @code{MAP_DROPPABLE} flag is specific to Linux. + @end vtable @code{mmap} returns the address of the new mapping, or diff --git a/sysdeps/unix/sysv/linux/bits/mman-linux.h b/sysdeps/unix/sysv/linux/bits/mman-linux.h index 522333c50a..161a885096 100644 --- a/sysdeps/unix/sysv/linux/bits/mman-linux.h +++ b/sysdeps/unix/sysv/linux/bits/mman-linux.h @@ -43,6 +43,7 @@ #define MAP_PRIVATE 0x02 /* Changes are private. */ #define MAP_SHARED_VALIDATE 0x03 /* Share changes and validate extension flags. */ +#define MAP_DROPPABLE 0x08 /* Zero memory under memory pressure. */ #define MAP_TYPE 0x0f /* Mask for type of mapping. */ /* Other flags. */
This request the page to be never written out to swap, it will be zeroed under memory pressure (so kernel can just drop the page), it is inherited by fork, it is not counted against @code{mlock} budget, and if there is no enough memory to service a page faults there is no fatal error (so not signal is sent). Tested with build-many-glibcs.py. --- manual/llio.texi | 9 +++++++++ sysdeps/unix/sysv/linux/bits/mman-linux.h | 1 + 2 files changed, 10 insertions(+)