RCCL Multinode DMA Buffer crash fix (#1682)

This commit handles DMABUF initialization and call appropriate handling function. This fixes crash in OS with no peermem support and relying on only DMABUF.

* Initial test commit
* Handling Dmabuf_fd opening and closing
* Cleanup
* Use DMABuff or Peermem as needed
* Using user input for ibDmaBufSupportInitOnce
* Revert all changes to rocmwrap.cc
* Revert all changes to rocmwrap.cc
* Changing to func definition braces
* Reverting line removal in utils.h
* useDmaBuf to calculate  flushEnabled

src/misc/utils.cc

@@ -8,7 +8,7 @@
 #include "core.h"
 
 #include "nvmlwrap.h"
-
+#include <unistd.h>
 #include <stdlib.h>
 
 // Get current Compute Capability
@@ -289,3 +289,22 @@ void ncclMemoryStackDestruct(struct ncclMemoryStack* me) {
     h = h1;
   }
 }
+
+size_t get_sc_page_size() {
+  static size_t cached_page_size = 0;
+  size_t ps = __atomic_load_n(&cached_page_size,__ATOMIC_RELAXED);
+  if (ps == 0) {
+      ps = (size_t)sysconf(_SC_PAGESIZE);
+      __atomic_store_n(&cached_page_size, ps,__ATOMIC_RELAXED);
+  }
+  return ps;
+}
+
+void get_aligned_ptr_and_size(const void *ptr, const size_t bufsize, void **aligned_ptr, size_t *aligned_size) {
+  if (!aligned_ptr || !aligned_size) return;
+  const size_t page_size = get_sc_page_size();
+  uintptr_t aligned_ptr_local = (uintptr_t)ptr & ~(page_size - 1);
+  size_t local_offset = (size_t)((uintptr_t)ptr - aligned_ptr_local);
+  *aligned_size = (bufsize + local_offset + page_size - 1) & ~(page_size - 1);
+  *aligned_ptr = (void *)aligned_ptr_local;
+}