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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-10-08 15:45:26 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2024-10-10 10:27:53 -0300 |
| commit | f6e849fd7ce2a8954022bd23b94703975b3db0d1 (patch) | |
| tree | e1661f1fbbe81a2e00a6073c3c011bb21a6e9985 | |
| parent | 86f06282ccb1b11de7a07fc10f7b77991b7d121a (diff) | |
| download | glibc-f6e849fd7ce2a8954022bd23b94703975b3db0d1.zip glibc-f6e849fd7ce2a8954022bd23b94703975b3db0d1.tar.gz glibc-f6e849fd7ce2a8954022bd23b94703975b3db0d1.tar.bz2 | |
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 <hjl.tools@gmail.com>
| -rw-r--r-- | manual/llio.texi | 9 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/bits/mman-linux.h | 1 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/tst-mman-consts.py | 2 |
3 files changed, 11 insertions, 1 deletions
diff --git a/manual/llio.texi b/manual/llio.texi index a035c3e..05ab44c 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 +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 522333c..161a885 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 a1137eb..2191bea 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 <sys/mman.h>\n', |