unix: add SetMemPolicy and its mode/flag values

This reuses CPUSet type as it fits perfectly.

No GetMemPolicy support yet.

Change-Id: I549361bc1ed95ee73fd38d00277ec0f9f348a9ba
Reviewed-on: https://go-review.googlesource.com/c/sys/+/706917
Auto-Submit: Michael Pratt <[email protected]>
Reviewed-by: Antti Kervinen <[email protected]>
Reviewed-by: Tobias Klauser <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Michael Pratt <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>

Author: kolyshkin

unix/linux/types.go

@@ -135,6 +135,7 @@ struct termios2 {
 #include <linux/landlock.h>
 #include <linux/loop.h>
 #include <linux/lwtunnel.h>
+#include <linux/mempolicy.h>
 #include <linux/mpls_iptunnel.h>
 #include <linux/ncsi.h>
 #include <linux/net_namespace.h>
@@ -6250,3 +6251,34 @@ type SockDiagReq C.struct_sock_diag_req
 
 // Removed in Linux 6.13, kept for backwards compatibility.
 const RTM_NEWNVLAN = 0x70
+
+// Memory policy modes and flags for [SetMemPolicy], as defined in /usr/include/linux/mempolicy.h.
+// Not all can be used, see set_mempolicy(2).
+// Generated by:
+// $ { perl -nlE '/^#define (MPOL_\w+)/ && say "\t$1 = C.$1"' /usr/include/linux/mempolicy.h; perl -nlE '/^\s*(MPOL_\w+)/ && say "\t$1 = C.$1"' /usr/include/linux/mempolicy.h; } | sort | uniq
+const (
+	MPOL_BIND                = C.MPOL_BIND
+	MPOL_DEFAULT             = C.MPOL_DEFAULT
+	MPOL_F_ADDR              = C.MPOL_F_ADDR
+	MPOL_F_MEMS_ALLOWED      = C.MPOL_F_MEMS_ALLOWED
+	MPOL_F_MOF               = C.MPOL_F_MOF
+	MPOL_F_MORON             = C.MPOL_F_MORON
+	MPOL_F_NODE              = C.MPOL_F_NODE
+	MPOL_F_NUMA_BALANCING    = C.MPOL_F_NUMA_BALANCING
+	MPOL_F_RELATIVE_NODES    = C.MPOL_F_RELATIVE_NODES
+	MPOL_F_SHARED            = C.MPOL_F_SHARED
+	MPOL_F_STATIC_NODES      = C.MPOL_F_STATIC_NODES
+	MPOL_INTERLEAVE          = C.MPOL_INTERLEAVE
+	MPOL_LOCAL               = C.MPOL_LOCAL
+	MPOL_MAX                 = C.MPOL_MAX
+	MPOL_MF_INTERNAL         = C.MPOL_MF_INTERNAL
+	MPOL_MF_LAZY             = C.MPOL_MF_LAZY
+	MPOL_MF_MOVE_ALL         = C.MPOL_MF_MOVE_ALL
+	MPOL_MF_MOVE             = C.MPOL_MF_MOVE
+	MPOL_MF_STRICT           = C.MPOL_MF_STRICT
+	MPOL_MF_VALID            = C.MPOL_MF_VALID
+	MPOL_MODE_FLAGS          = C.MPOL_MODE_FLAGS
+	MPOL_PREFERRED           = C.MPOL_PREFERRED
+	MPOL_PREFERRED_MANY      = C.MPOL_PREFERRED_MANY
+	MPOL_WEIGHTED_INTERLEAVE = C.MPOL_WEIGHTED_INTERLEAVE
+)

unix/syscall_linux.go

@@ -2643,3 +2643,9 @@ func SchedGetAttr(pid int, flags uint) (*SchedAttr, error) {
 
 //sys	Cachestat(fd uint, crange *CachestatRange, cstat *Cachestat_t, flags uint) (err error)
 //sys	Mseal(b []byte, flags uint) (err error)
+
+//sys	setMemPolicy(mode int, mask *CPUSet, size int) (err error) = SYS_SET_MEMPOLICY
+
+func SetMemPolicy(mode int, mask *CPUSet) error {
+	return setMemPolicy(mode, mask, _CPU_SETSIZE)
+}