CrOS: memory: Rename pagemap methods and add a helper

Because the pagemap uses the term present instead of in core
we will rename those methods.

Additionally, we add a little helper called IsFullyPresent.

Bug: chromium:1067833
Change-Id: I98099cdd1afa5ed0bc3ded3f22592000719281a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2462687Reviewed-by: Kuo-Hsin Yang <vovoy@chromium.org>
Commit-Queue: Brian Geffon <bgeffon@chromium.org>
Auto-Submit: Brian Geffon <bgeffon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#815441}

chromeos/memory/pagemap.cc

@@ -9,6 +9,7 @@
 #include <sys/types.h>
 #include <string>
 
+#include "base/logging.h"
 #include "base/memory/aligned_memory.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/process/process_metrics.h"
@@ -78,11 +79,11 @@ bool Pagemap::GetEntries(uint64_t address,
   return true;
 }
 
-bool Pagemap::GetNumberOfPagesInCore(uint64_t address,
-                                     uint64_t length,
-                                     uint64_t* pages_in_core) const {
-  DCHECK(pages_in_core);
-  *pages_in_core = 0;
+bool Pagemap::GetNumberOfPagesPresent(uint64_t address,
+                                      uint64_t length,
+                                      uint64_t* pages_present) const {
+  DCHECK(pages_present);
+  *pages_present = 0;
 
   std::vector<Pagemap::PagemapEntry> entries(length / base::GetPageSize());
   if (!GetEntries(address, length, &entries)) {
@@ -91,11 +92,21 @@ bool Pagemap::GetNumberOfPagesInCore(uint64_t address,
 
   for (const Pagemap::PagemapEntry& entry : entries) {
     if (entry.page_present)
-      (*pages_in_core)++;
+      (*pages_present)++;
   }
 
   return true;
 }
 
+bool Pagemap::IsFullyPresent(uint64_t address, uint64_t length) const {
+  const size_t kPageSize = base::GetPageSize();
+  uint64_t pages_present = 0;
+  if (!GetNumberOfPagesPresent(address, length, &pages_present)) {
+    LOG(WARNING) << "Unable to get pagemap entry";
+    return false;
+  }
+  return (length / kPageSize) == pages_present;
+}
+
 }  // namespace memory
 }  // namespace chromeos

chromeos/memory/pagemap.h

@@ -49,13 +49,17 @@ class CHROMEOS_EXPORT Pagemap {
                   uint64_t length,
                   std::vector<PagemapEntry>* entries) const;
 
-  // GetNumberOfPagesInCore is a helper which makes it easy to quickly determine
-  // the number of pages in core for the region specified by |address| and
-  // |length|. On success the function will return true and pages_in_core will
-  // be set accordingly.
-  bool GetNumberOfPagesInCore(uint64_t address,
-                              uint64_t length,
-                              uint64_t* pages_in_core) const;
+  // GetNumberOfPagesPresent is a helper which makes it easy to quickly
+  // determine the number of pages in core for the region specified by |address|
+  // and |length|. On success the function will return true and pages_present
+  // will be set accordingly.
+  bool GetNumberOfPagesPresent(uint64_t address,
+                               uint64_t length,
+                               uint64_t* pages_present) const;
+
+  // IsFullyPresent is a small helper around GetNumberOfPagesPresent which
+  // returns true if every page in the range is presnt.
+  bool IsFullyPresent(uint64_t address, uint64_t length) const;
 
  private:
   friend class PagemapTest;