libfuse: remove libnuma dependency

As discussed on https://github.com/libfuse/libfuse/issues/1515, libfuse has
a very light dependency on libnuma, only using very light wrappers over
mmap, mbind, and munmap. Remove the libnuma dependency by calling those
syscalls directly.

Populate memory after mmap to avoid SIGBUS later.

Signed-off-by: Benjamin Peterson <benjamin@python.org>

.github/workflows/install-ubuntu-dependencies.sh

@@ -11,7 +11,6 @@ PACKAGES_CORE=(
     ninja-build
     libudev-dev
     liburing-dev
-    libnuma-dev
     pkg-config
     python3
     python3-pip

doc/README.fuse-io-uring

@@ -34,5 +34,4 @@ Requirements:
 
 Build Dependencies:
 - liburing (for io_uring support)
-- libnuma (required alongside liburing)
 - meson build system with option: -Denable-io-uring=true

lib/fuse_uring.c

@@ -22,7 +22,9 @@
 #include <stdbool.h>
 #include <string.h>
 #include <unistd.h>
-#include <numa.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <linux/mempolicy.h>
 #include <pthread.h>
 #include <stdio.h>
 #include <linux/sched.h>
@@ -418,8 +420,8 @@ static void fuse_session_destruct_uring(struct fuse_ring_pool *fuse_ring)
 		for (size_t idx = 0; idx < fuse_ring->queue_depth; idx++) {
 			struct fuse_ring_ent *ent = &queue->ent[idx];
 
-			numa_free(ent->op_payload, ent->req_payload_sz);
-			numa_free(ent->req_header, queue->req_header_sz);
+			munmap(ent->op_payload, ent->req_payload_sz);
+			munmap(ent->req_header, queue->req_header_sz);
 		}
 
 		pthread_mutex_destroy(&queue->ring_lock);
@@ -732,6 +734,18 @@ static void fuse_uring_set_thread_core(int qid)
 	}
 }
 
+static void *alloc_local(size_t size)
+{
+	void *p = mmap(NULL, size, PROT_READ | PROT_WRITE,
+		       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	if (p == MAP_FAILED)
+		return NULL;
+	syscall(SYS_mbind, p, size, MPOL_LOCAL, NULL, 0, 0);
+	if (madvise(p, size, MADV_POPULATE_WRITE) < 0)
+		return NULL;
+	return p;
+}
+
 /*
  * @return negative error code or io-uring file descriptor
  */
@@ -773,14 +787,13 @@ static int fuse_uring_init_queue(struct fuse_ring_queue *queue)
 		 * Also allocate the header to have it page aligned, which
 		 * is a requirement for page pinning
 		 */
-		ring_ent->req_header =
-			numa_alloc_local(queue->req_header_sz);
+		ring_ent->req_header = alloc_local(queue->req_header_sz);
 		if (!ring_ent->req_header)
 			return -ENOMEM;
+
 		ring_ent->req_payload_sz = ring->max_req_payload_sz;
 
-		ring_ent->op_payload =
-			numa_alloc_local(ring_ent->req_payload_sz);
+		ring_ent->op_payload = alloc_local(ring_ent->req_payload_sz);
 		if (!ring_ent->op_payload)
 			return -ENOMEM;
 

lib/meson.build

@@ -32,7 +32,6 @@ endif
 if private_cfg.get('HAVE_URING', false)
   libfuse_sources += [ 'fuse_uring.c' ]
   deps += [ dependency('liburing') ]
-  deps += [ dependency('numa') ]
 endif
 
 

meson.build

@@ -204,9 +204,8 @@ int main(void) {
 }'''
 
 liburing = dependency('liburing', required: false)
-libnuma = dependency('numa', required: false)
 
-if get_option('enable-io-uring') and liburing.found() and libnuma.found()
+if get_option('enable-io-uring') and liburing.found()
    if cc.links(code,
               name: 'liburing linking and SQE128 support',
               dependencies: [liburing])