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authorAlice Ryhl <aliceryhl@google.com>2024-06-07 08:23:41 +0000
committerMiguel Ojeda <ojeda@kernel.org>2024-07-08 22:39:39 +0200
commitab44079e2869c9f1743d167d5f9b5befe375b6d9 (patch)
tree3e0b69e1c73d2b7879aacda1ac3ec77b4c3c8719 /rust/bindings
parentd3ee24cce4e558041cbf21a5bc9cd9a4b1b3c7e7 (diff)
rust: alloc: add __GFP_HIGHMEM flag
Make it possible to allocate memory that doesn't need to mapped into the kernel's address space. This flag is useful together with Page::alloc_page [1]. Rust Binder needs this for the memory that holds incoming transactions for each process. Each process will have a few megabytes of memory allocated with this flag, which is mapped into the process using vm_insert_page. When the kernel copies data for an incoming transaction into a process's memory region, it will use kmap_local_page to temporarily map pages that are being modified. There is no need for them to take up address space in the kernel when the kernel is not writing an incoming transaction into the page. Link: https://lore.kernel.org/all/20240528-alice-mm-v7-4-78222c31b8f4@google.com/ [1] Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240607-highmem-v1-1-d18c5ca4072f@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Diffstat (limited to 'rust/bindings')
-rw-r--r--rust/bindings/bindings_helper.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index ddb5644d4fd9..52a1412338ef 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -25,3 +25,4 @@ const gfp_t RUST_CONST_HELPER_GFP_KERNEL = GFP_KERNEL;
const gfp_t RUST_CONST_HELPER_GFP_KERNEL_ACCOUNT = GFP_KERNEL_ACCOUNT;
const gfp_t RUST_CONST_HELPER_GFP_NOWAIT = GFP_NOWAIT;
const gfp_t RUST_CONST_HELPER___GFP_ZERO = __GFP_ZERO;
+const gfp_t RUST_CONST_HELPER___GFP_HIGHMEM = ___GFP_HIGHMEM;