commit f6e849fd7ce2a8954022bd23b94703975b3db0d1 Author: Adhemerval Zanella Date: Tue Oct 8 15:45:26 2024 -0300 linux: Add MAP_DROPPABLE from Linux 6.11 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. Reviewed-by: H.J. Lu diff --git a/manual/llio.texi b/manual/llio.texi index 17fe1181d5cc2cef..a8ed72c5db6ecba9 100644 --- a/manual/llio.texi +++ b/manual/llio.texi @@ -1647,6 +1647,15 @@ The @code{MAP_HUGETLB} flag is specific to Linux. @c user programs (and I don't understand the last two). MAP_LOCKED does @c not appear to be implemented. +@item MAP_DROPPABLE +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 +not enough memory to service a page fault there is no fatal error (so no +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 522333c50a04481d..161a88509682cf69 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. */ diff --git a/sysdeps/unix/sysv/linux/tst-mman-consts.py b/sysdeps/unix/sysv/linux/tst-mman-consts.py index a1137eb1d59d95ec..2191bea36f8f69e0 100644 --- a/sysdeps/unix/sysv/linux/tst-mman-consts.py +++ b/sysdeps/unix/sysv/linux/tst-mman-consts.py @@ -33,7 +33,7 @@ def main(): help='C compiler (including options) to use') args = parser.parse_args() linux_version_headers = glibcsyscalls.linux_kernel_version(args.cc) - linux_version_glibc = (6, 10) + linux_version_glibc = (6, 11) sys.exit(glibcextract.compare_macro_consts( '#define _GNU_SOURCE 1\n' '#include \n',