X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/4ab643073d9631ac079bd1cd9048c8c2420c4994..037ed0177fab7a21eee2439624cbb4c4db8ccc31:/src/mc/mc_page_snapshot.cpp

diff --git a/src/mc/mc_page_snapshot.cpp b/src/mc/mc_page_snapshot.cpp
index 60ff820bc4..79caa3af30 100644
--- a/src/mc/mc_page_snapshot.cpp
+++ b/src/mc/mc_page_snapshot.cpp
@@ -1,6 +1,9 @@
+#include <unistd.h> // pread, pwrite
+
 #include "mc_page_store.h"
 #include "mc_mmu.h"
 #include "mc_private.h"
+#include "mc_snapshot.h"
 
 #include <xbt/mmalloc.h>
 
@@ -19,10 +22,17 @@ extern "C" {
  *  @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
  *  @return                Snapshot page numbers of this new snapshot
  */
-size_t* mc_take_page_snapshot_region(void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
+size_t* mc_take_page_snapshot_region(mc_process_t process,
+  void* data, size_t page_count, uint64_t* pagemap, size_t* reference_pages)
 {
   size_t* pagenos = (size_t*) malloc(page_count * sizeof(size_t));
 
+  const bool is_self = MC_process_is_self(process);
+
+  void* temp = NULL;
+  if (!is_self)
+    temp = malloc(xbt_pagebits);
+
   for (size_t i=0; i!=page_count; ++i) {
     bool softclean = pagemap && !(pagemap[i] & SOFT_DIRTY);
     if (softclean && reference_pages) {
@@ -33,10 +43,26 @@ size_t* mc_take_page_snapshot_region(void* data, size_t page_count, uint64_t* pa
       // Otherwise, we need to store the page the hard way
       // (by reading its content):
       void* page = (char*) data + (i << xbt_pagebits);
-      pagenos[i] = mc_model_checker->pages->store_page(page);
+      xbt_assert(mc_page_offset(page)==0, "Not at the beginning of a page");
+      void* page_data;
+      if (is_self) {
+        page_data = page;
+      } else {
+        /* Adding another copy (and a syscall) will probably slow things a lot.
+           TODO, optimize this somehow (at least by grouping the syscalls)
+           if needed. Either:
+            - reduce the number of syscalls;
+            - let the application snapshot itself;
+            - move the segments in shared memory (this will break `fork` however).
+        */
+        page_data = temp;
+        MC_process_read(process, temp, page, xbt_pagesize);
+      }
+      pagenos[i] = mc_model_checker->pages->store_page(page_data);
     }
   }
 
+  free(temp);
   return pagenos;
 }
 
@@ -58,7 +84,8 @@ void mc_free_page_snapshot_region(size_t* pagenos, size_t page_count)
  *  @param pagemap         Linux kernel pagemap values fot this region (or NULL)
  *  @param reference_pages Snapshot page numbers of the previous soft_dirty_reset (or NULL)
  */
-void mc_restore_page_snapshot_region(void* start_addr, size_t page_count, size_t* pagenos, uint64_t* pagemap, size_t* reference_pagenos)
+void mc_restore_page_snapshot_region(mc_process_t process,
+  void* start_addr, size_t page_count, size_t* pagenos, uint64_t* pagemap, size_t* reference_pagenos)
 {
   for (size_t i=0; i!=page_count; ++i) {
 
@@ -72,7 +99,7 @@ void mc_restore_page_snapshot_region(void* start_addr, size_t page_count, size_t
     // Otherwise, copy the page:
     void* target_page = mc_page_from_number(start_addr, i);
     const void* source_page = mc_model_checker->pages->get_page(pagenos[i]);
-    memcpy(target_page, source_page, xbt_pagesize);
+    MC_process_write(process, source_page, target_page, xbt_pagesize);
   }
 }
 
@@ -158,15 +185,18 @@ static void mc_read_pagemap(uint64_t* pagemap, size_t page_start, size_t page_co
 
 // ***** High level API
 
-mc_mem_region_t mc_region_new_sparse(int type, void *start_addr, void* permanent_addr, size_t size, mc_mem_region_t ref_reg)
+mc_mem_region_t mc_region_new_sparse(mc_region_type_t region_type,
+  void *start_addr, void* permanent_addr, size_t size,
+  mc_mem_region_t ref_reg)
 {
-  mc_mem_region_t new_reg = xbt_new(s_mc_mem_region_t, 1);
+  mc_process_t process = &mc_model_checker->process;
 
-  new_reg->start_addr = start_addr;
-  new_reg->permanent_addr = permanent_addr;
-  new_reg->data = NULL;
-  new_reg->size = size;
-  new_reg->page_numbers = NULL;
+  mc_mem_region_t region = xbt_new(s_mc_mem_region_t, 1);
+  region->region_type = region_type;
+  region->storage_type = MC_REGION_STORAGE_TYPE_CHUNKED;
+  region->start_addr = start_addr;
+  region->permanent_addr = permanent_addr;
+  region->size = size;
 
   xbt_assert((((uintptr_t)start_addr) & (xbt_pagesize-1)) == 0,
     "Not at the beginning of a page");
@@ -175,22 +205,27 @@ mc_mem_region_t mc_region_new_sparse(int type, void *start_addr, void* permanent
   size_t page_count = mc_page_count(size);
 
   uint64_t* pagemap = NULL;
-  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
-      pagemap = (uint64_t*) mmalloc_no_memset((xbt_mheap_t) mc_heap, sizeof(uint64_t) * page_count);
+  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot &&
+      MC_process_is_self(process)) {
+      pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
       mc_read_pagemap(pagemap, mc_page_number(NULL, permanent_addr), page_count);
   }
 
+  size_t* reg_page_numbers = NULL;
+  if (ref_reg!=NULL && ref_reg->storage_type == MC_REGION_STORAGE_TYPE_CHUNKED)
+    reg_page_numbers = ref_reg->chunked.page_numbers;
+
   // Take incremental snapshot:
-  new_reg->page_numbers = mc_take_page_snapshot_region(permanent_addr, page_count, pagemap,
-    ref_reg==NULL ? NULL : ref_reg->page_numbers);
+  region->chunked.page_numbers = mc_take_page_snapshot_region(process,
+    permanent_addr, page_count, pagemap, reg_page_numbers);
 
   if(pagemap) {
-    mfree((xbt_mheap_t) mc_heap, pagemap);
+    mfree(mc_heap, pagemap);
   }
-  return new_reg;
+  return region;
 }
 
-void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
+void mc_region_restore_sparse(mc_process_t process, mc_mem_region_t reg, mc_mem_region_t ref_reg)
 {
   xbt_assert((((uintptr_t)reg->permanent_addr) & (xbt_pagesize-1)) == 0,
     "Not at the beginning of a page");
@@ -199,14 +234,20 @@ void mc_region_restore_sparse(mc_mem_region_t reg, mc_mem_region_t ref_reg)
   uint64_t* pagemap = NULL;
 
   // Read soft-dirty bits if necessary in order to know which pages have changed:
-  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot) {
-    pagemap = (uint64_t*) mmalloc_no_memset((xbt_mheap_t) mc_heap, sizeof(uint64_t) * page_count);
+  if (_sg_mc_soft_dirty && mc_model_checker->parent_snapshot
+      && MC_process_is_self(process)) {
+    pagemap = (uint64_t*) mmalloc_no_memset(mc_heap, sizeof(uint64_t) * page_count);
     mc_read_pagemap(pagemap, mc_page_number(NULL, reg->permanent_addr), page_count);
   }
 
-  // Incremental per-page snapshot restoration:
-  mc_restore_page_snapshot_region(reg->permanent_addr, page_count, reg->page_numbers,
-    pagemap, ref_reg ? ref_reg->page_numbers : NULL);
+  // Incremental per-page snapshot restoration:s
+  size_t* reg_page_numbers = NULL;
+  if (ref_reg && ref_reg->storage_type == MC_REGION_STORAGE_TYPE_CHUNKED)
+    reg_page_numbers = ref_reg->chunked.page_numbers;
+
+  mc_restore_page_snapshot_region(process,
+    reg->permanent_addr, page_count, reg->chunked.page_numbers,
+    pagemap, reg_page_numbers);
 
   if(pagemap) {
     free(pagemap);