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From:   Gregory Price <gourry.memverge@gmail.com>
To:     linux-mm@kvack.org, jgroves@micron.com, ravis.opensrc@micron.com,
        sthanneeru@micron.com, emirakhur@micron.com, Hasan.Maruf@amd.com
Cc:     linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
        arnd@arndb.de, tglx@linutronix.de, luto@kernel.org,
        mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
        x86@kernel.org, hpa@zytor.com, mhocko@kernel.org, tj@kernel.org,
        ying.huang@intel.com, gregory.price@memverge.com, corbet@lwn.net,
        rakie.kim@sk.com, hyeongtak.ji@sk.com, honggyu.kim@sk.com,
        vtavarespetr@micron.com, peterz@infradead.org,
        Michal Hocko <mhocko@suse.com>
Subject: [RFC PATCH 08/11] mm/mempolicy: add set_mempolicy2 syscall
Date:   Wed,  6 Dec 2023 19:27:56 -0500
Message-Id: <20231207002759.51418-9-gregory.price@memverge.com>
In-Reply-To: <20231207002759.51418-1-gregory.price@memverge.com>
References: <20231207002759.51418-1-gregory.price@memverge.com>
MIME-Version: 1.0
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Precedence: bulk

set_mempolicy2 is an extensible set_mempolicy interface which allows
a user to set the per-task memory policy.

Defined as:

set_mempolicy2(struct mpol_args *args, size_t size, unsigned long flags);

relevant mpol_args fields include the following:

mode:         The MPOL_* policy (DEFAULT, INTERLEAVE, etc.)
mode_flags:   The MPOL_F_* flags that were previously passed in or'd
              into the mode.  This was split to hopefully allow future
              extensions additional mode/flag space.
pol_nodes:    the nodemask to apply for the memory policy
pol_maxnodes: The max number of nodes described by pol_nodes

The usize arg is intended for the user to pass in sizeof(mpol_args)
to allow forward/backward compatibility whenever possible.

The flags argument is intended to future proof the syscall against
future extensions which may require interpreting the arguments in
the structure differently.

Semantics of `set_mempolicy` are otherwise the same as `set_mempolicy`
as of this patch.

Suggested-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Gregory Price <gregory.price@memverge.com>
---
 .../admin-guide/mm/numa_memory_policy.rst     | 10 ++++++
 arch/alpha/kernel/syscalls/syscall.tbl        |  1 +
 arch/arm/tools/syscall.tbl                    |  1 +
 arch/m68k/kernel/syscalls/syscall.tbl         |  1 +
 arch/microblaze/kernel/syscalls/syscall.tbl   |  1 +
 arch/mips/kernel/syscalls/syscall_n32.tbl     |  1 +
 arch/mips/kernel/syscalls/syscall_o32.tbl     |  1 +
 arch/parisc/kernel/syscalls/syscall.tbl       |  1 +
 arch/powerpc/kernel/syscalls/syscall.tbl      |  1 +
 arch/s390/kernel/syscalls/syscall.tbl         |  1 +
 arch/sh/kernel/syscalls/syscall.tbl           |  1 +
 arch/sparc/kernel/syscalls/syscall.tbl        |  1 +
 arch/x86/entry/syscalls/syscall_32.tbl        |  1 +
 arch/x86/entry/syscalls/syscall_64.tbl        |  1 +
 arch/xtensa/kernel/syscalls/syscall.tbl       |  1 +
 include/linux/syscalls.h                      |  2 ++
 include/uapi/asm-generic/unistd.h             |  4 ++-
 mm/mempolicy.c                                | 34 +++++++++++++++++++
 18 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst
index 6d645519c2c1..7195edaeaad9 100644
--- a/Documentation/admin-guide/mm/numa_memory_policy.rst
+++ b/Documentation/admin-guide/mm/numa_memory_policy.rst
@@ -438,6 +438,8 @@ Set [Task] Memory Policy::
 
 	long set_mempolicy(int mode, const unsigned long *nmask,
 					unsigned long maxnode);
+	long set_mempolicy2(struct mpol_args args, size_t size,
+			    unsigned long flags);
 
 Set's the calling task's "task/process memory policy" to mode
 specified by the 'mode' argument and the set of nodes defined by
@@ -446,6 +448,12 @@ specified by the 'mode' argument and the set of nodes defined by
 'mode' argument with the flag (for example: MPOL_INTERLEAVE |
 MPOL_F_STATIC_NODES).
 
+set_mempolicy2() is an extended version of set_mempolicy() capable
+of setting a mempolicy which requires more information than can be
+passed via get_mempolicy().  For example, weighted interleave with
+task-local weights requires a weight array to be passed via the
+'mpol_args->il_weights' argument in the 'struct mpol_args' arg.
+
 See the set_mempolicy(2) man page for more details
 
 
@@ -515,6 +523,8 @@ Extended Mempolicy Arguments::
 The extended mempolicy argument structure is defined to allow the mempolicy
 interfaces future extensibility without the need for additional system calls.
 
+Extended interfaces (set_mempolicy2) use this argument structure.
+
 The core arguments (mode, mode_flags, pol_nodes, and pol_maxnodes) apply to
 all interfaces relative to their non-extended counterparts. Each additional
 field may only apply to specific extended interfaces.  See the respective
diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 18c842ca6c32..0dc288a1118a 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -496,3 +496,4 @@
 564	common	futex_wake			sys_futex_wake
 565	common	futex_wait			sys_futex_wait
 566	common	futex_requeue			sys_futex_requeue
+567	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 584f9528c996..50172ec0e1f5 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -470,3 +470,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index 7a4b780e82cb..839d90c535f2 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -456,3 +456,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 5b6a0b02b7de..567c8b883735 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -462,3 +462,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index a842b41c8e06..cc0640e16f2f 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -395,3 +395,4 @@
 454	n32	futex_wake			sys_futex_wake
 455	n32	futex_wait			sys_futex_wait
 456	n32	futex_requeue			sys_futex_requeue
+457	n32	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 525cc54bc63b..f7262fde98d9 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -444,3 +444,4 @@
 454	o32	futex_wake			sys_futex_wake
 455	o32	futex_wait			sys_futex_wait
 456	o32	futex_requeue			sys_futex_requeue
+457	o32	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index a47798fed54e..e10f0e8bd064 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -455,3 +455,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 7fab411378f2..4f03f5f42b78 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -543,3 +543,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 86fec9b080f6..f98dadc2e9df 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -459,3 +459,4 @@
 454  common	futex_wake		sys_futex_wake			sys_futex_wake
 455  common	futex_wait		sys_futex_wait			sys_futex_wait
 456  common	futex_requeue		sys_futex_requeue		sys_futex_requeue
+457  common	set_mempolicy2		sys_set_mempolicy2		sys_set_mempolicy2
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index 363fae0fe9bf..f47ba9f2d05d 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -459,3 +459,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 7bcaa3d5ea44..53fb16616728 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -502,3 +502,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c8fac5205803..4b4dc41b24ee 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -461,3 +461,4 @@
 454	i386	futex_wake		sys_futex_wake
 455	i386	futex_wait		sys_futex_wait
 456	i386	futex_requeue		sys_futex_requeue
+457	i386	set_mempolicy2		sys_set_mempolicy2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 8cb8bf68721c..1bc2190bec27 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -378,6 +378,7 @@
 454	common	futex_wake		sys_futex_wake
 455	common	futex_wait		sys_futex_wait
 456	common	futex_requeue		sys_futex_requeue
+457	common	set_mempolicy2		sys_set_mempolicy2
 
 #
 # Due to a historical design error, certain syscalls are numbered differently
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 06eefa9c1458..e26dc89399eb 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -427,3 +427,4 @@
 454	common	futex_wake			sys_futex_wake
 455	common	futex_wait			sys_futex_wait
 456	common	futex_requeue			sys_futex_requeue
+457	common	set_mempolicy2			sys_set_mempolicy2
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index fd9d12de7e92..3244cd990858 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -822,6 +822,8 @@ asmlinkage long sys_get_mempolicy(int __user *policy,
 				unsigned long addr, unsigned long flags);
 asmlinkage long sys_set_mempolicy(int mode, const unsigned long __user *nmask,
 				unsigned long maxnode);
+asmlinkage long sys_set_mempolicy2(struct mpol_args *args, size_t size,
+				   unsigned long flags);
 asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
 				const unsigned long __user *from,
 				const unsigned long __user *to);
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 756b013fb832..55486aba099f 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -828,9 +828,11 @@ __SYSCALL(__NR_futex_wake, sys_futex_wake)
 __SYSCALL(__NR_futex_wait, sys_futex_wait)
 #define __NR_futex_requeue 456
 __SYSCALL(__NR_futex_requeue, sys_futex_requeue)
+#define __NR_set_mempolicy2 457
+__SYSCALL(__NR_set_mempolicy2, sys_set_mempolicy2)
 
 #undef __NR_syscalls
-#define __NR_syscalls 457
+#define __NR_syscalls 458
 
 /*
  * 32 bit systems traditionally used different
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 4be63547a4b3..fdc56798226b 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1636,6 +1636,40 @@ SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
 	return kernel_set_mempolicy(mode, nmask, maxnode);
 }
 
+SYSCALL_DEFINE3(set_mempolicy2, struct mpol_args __user *, uargs, size_t, usize,
+		unsigned long, flags)
+{
+	struct mpol_args kargs;
+	struct mempolicy_args margs;
+	int err;
+	nodemask_t policy_nodemask;
+
+	if (flags)
+		return -EINVAL;
+
+	err = copy_struct_from_user(&kargs, sizeof(kargs), uargs, usize);
+	if (err)
+		return err;
+
+	err = validate_mpol_flags(kargs.mode, &kargs.mode_flags);
+	if (err)
+		return err;
+
+	memset(&margs, '\0', sizeof(margs));
+	margs.mode = kargs.mode;
+	margs.mode_flags = kargs.mode_flags;
+	if (kargs.pol_nodes) {
+		err = get_nodes(&policy_nodemask, kargs.pol_nodes,
+				kargs.pol_maxnodes);
+		if (err)
+			return err;
+		margs.policy_nodes = &policy_nodemask;
+	} else
+		margs.policy_nodes = NULL;
+
+	return do_set_mempolicy(&margs);
+}
+
 static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
 				const unsigned long __user *old_nodes,
 				const unsigned long __user *new_nodes)
-- 
2.39.1