Re: [PATCH v6 08/12] mm/mempolicy: add userland mempolicy arg structure
From: Randy Dunlap <hidden>
Date: 2024-01-04 00:19:13
Also in:
linux-arch, linux-doc, linux-fsdevel, linux-mm, lkml
Hi, On 1/3/24 14:42, Gregory Price wrote:
quoted hunk ↗ jump to hunk
This patch adds the new user-api argument structure intended for set_mempolicy2 and mbind2. struct mpol_param { __u16 mode; __u16 mode_flags; __s32 home_node; /* mbind2: policy home node */ __u16 pol_maxnodes; __u8 resv[6]; __aligned_u64 *pol_nodes; }; This structure is intended to be extensible as new mempolicy extensions are added. For example, set_mempolicy_home_node was added to allow vma mempolicies to have a preferred/home node assigned. This structure allows the user to set the home node at the time mempolicy is created, rather than requiring an additional syscalls. Full breakdown of arguments as of this patch: mode: Mempolicy mode (MPOL_DEFAULT, MPOL_INTERLEAVE) mode_flags: Flags previously or'd into mode in set_mempolicy (e.g.: MPOL_F_STATIC_NODES, MPOL_F_RELATIVE_NODES) home_node: for mbind2. Allows the setting of a policy's home with the use of MPOL_MF_HOME_NODE pol_maxnodes: Max number of nodes in the policy nodemask pol_nodes: Policy nodemask The reserved field accounts explicitly for a potential memory hole in the structure. Suggested-by: Frank van der Linden <redacted> Suggested-by: Vinicius Tavares Petrucci <redacted> Suggested-by: Hasan Al Maruf <redacted> Signed-off-by: Gregory Price <redacted> Co-developed-by: Vinicius Tavares Petrucci <redacted> Signed-off-by: Vinicius Tavares Petrucci <redacted> --- .../admin-guide/mm/numa_memory_policy.rst | 17 +++++++++++++++++ include/linux/syscalls.h | 1 + include/uapi/linux/mempolicy.h | 9 +++++++++ 3 files changed, 27 insertions(+)diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst index a70f20ce1ffb..cbfc5f65ed77 100644 --- a/Documentation/admin-guide/mm/numa_memory_policy.rst +++ b/Documentation/admin-guide/mm/numa_memory_policy.rst@@ -480,6 +480,23 @@ closest to which page allocation will come from. Specifying the home node overri the default allocation policy to allocate memory close to the local node for an executing CPU. +Extended Mempolicy Arguments:: + + struct mpol_param { + __u16 mode; + __u16 mode_flags; + __s32 home_node; /* mbind2: set home node */ + __u64 pol_maxnodes; + __aligned_u64 pol_nodes; /* nodemask pointer */ + };
Can you make the above documentation struct agree with the struct in the header below, please? (just a difference in the size of pol_maxnodes and the 'resv' bytes)
+The extended mempolicy argument structure is defined to allow the mempolicy +interfaces future extensibility without the need for additional system calls. + +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 +extended interface man page for more details. Memory Policy Command Line Interface ====================================
quoted hunk ↗ jump to hunk
diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h index 1f9bb10d1a47..109788c8be92 100644 --- a/include/uapi/linux/mempolicy.h +++ b/include/uapi/linux/mempolicy.h@@ -27,6 +27,15 @@ enum { MPOL_MAX, /* always last member of enum */ }; +struct mpol_param { + __u16 mode; + __u16 mode_flags; + __s32 home_node; /* mbind2: policy home node */ + __u16 pol_maxnodes; + __u8 resv[6]; + __aligned_u64 pol_nodes; +}; + /* Flags for set_mempolicy */ #define MPOL_F_STATIC_NODES (1 << 15) #define MPOL_F_RELATIVE_NODES (1 << 14)
-- #Randy