[gold][patch] Control caching of memory mapped regions
Cary Coutant
ccoutant@google.com
Thu Mar 11 00:13:00 GMT 2010
> The patch is OK. It's also OK if you change the name.
I changed it to is_permanent_view() to eliminate the "!", and added a
comment to the method explaining the connection to DATA_NOT_OWNED.
Here's the patch as committed.
-cary
* fileread.cc (File_read::~File_read): Don't delete whole_file_view_.
(File_read::open[1]): Remove initial mapping of whole_file_view_.
(File_read::open[2]): Add whole_file_view_ to list of views.
(File_read::make_view): Remove test of whole_file_view_.
(File_read::find_or_make_view): Create whole_file_view_ if
necessary.
(File_read::clear_views): Replace bool parameter with enum;
adjust all callers. Don't delete views with permanent data;
do delete cached views and views from archives if
--no-keep-files-mapped is set. Set whole_file_view_ to NULL
if clearing the corresponding view.
* fileread.h (File_read::Clear_views_mode): New enum.
(File_read::View::is_permanent_view): New method.
(File_read::clear_views): Replace bool parameter
with enum; adjust all callers.
* options.h (General_options): Change keep_files_mapped option;
add map_whole_files.
* readsyms.cc (Add_symbols::run): Delete sd_ object before
releasing the file.
* reloc.cc (Scan_relocs::run): Delete rd_ object before releasing
the file.
-------------- next part --------------
Index: fileread.cc
===================================================================
RCS file: /cvs/src/src/gold/fileread.cc,v
retrieving revision 1.61
diff -u -p -r1.61 fileread.cc
--- fileread.cc 24 Feb 2010 20:50:59 -0000 1.61
+++ fileread.cc 10 Mar 2010 17:27:50 -0000
@@ -115,9 +115,7 @@ File_read::~File_read()
this->is_descriptor_opened_ = false;
}
this->name_.clear();
- this->clear_views(true);
- if (this->whole_file_view_)
- delete this->whole_file_view_;
+ this->clear_views(CLEAR_VIEWS_ALL);
}
// Open the file.
@@ -144,23 +142,6 @@ File_read::open(const Task* task, const
this->size_ = s.st_size;
gold_debug(DEBUG_FILES, "Attempt to open %s succeeded",
this->name_.c_str());
-
- // Options may not yet be ready e.g. when reading a version
- // script. We then default to --no-keep-files-mapped.
- if (parameters->options_valid()
- && parameters->options().keep_files_mapped())
- {
- const unsigned char* contents = static_cast<const unsigned char*>(
- ::mmap(NULL, this->size_, PROT_READ, MAP_PRIVATE,
- this->descriptor_, 0));
- if (contents == MAP_FAILED)
- gold_fatal(_("%s: mmap failed: %s"), this->filename().c_str(),
- strerror(errno));
- this->whole_file_view_ = new View(0, this->size_, contents, 0, false,
- View::DATA_MMAPPED);
- this->mapped_bytes_ += this->size_;
- }
-
this->token_.add_writer(task);
}
@@ -180,6 +161,7 @@ File_read::open(const Task* task, const
this->name_ = name;
this->whole_file_view_ = new View(0, size, contents, 0, false,
View::DATA_NOT_OWNED);
+ this->add_view(this->whole_file_view_);
this->size_ = size;
this->token_.add_writer(task);
return true;
@@ -226,7 +208,7 @@ File_read::release()
// for releasing the descriptor.
if (this->object_count_ <= 1)
{
- this->clear_views(false);
+ this->clear_views(CLEAR_VIEWS_NORMAL);
if (this->is_descriptor_opened_)
{
release_descriptor(this->descriptor_, false);
@@ -428,7 +410,7 @@ File_read::make_view(off_t start, sectio
}
File_read::View* v;
- if (this->whole_file_view_ != NULL || byteshift != 0)
+ if (byteshift != 0)
{
unsigned char* p = new unsigned char[psize + byteshift];
memset(p, 0, byteshift);
@@ -484,6 +466,15 @@ File_read::find_or_make_view(off_t offse
byteshift = (target_size / 8) - byteshift;
}
+ // If --map-whole-files is set, make sure we have a
+ // whole file view. Options may not yet be ready, e.g.,
+ // when reading a version script. We then default to
+ // --no-keep-files-mapped.
+ if (this->whole_file_view_ == NULL
+ && parameters->options_valid()
+ && parameters->options().map_whole_files())
+ this->whole_file_view_ = this->make_view(0, this->size_, 0, cache);
+
// Try to find a View with the required BYTESHIFT.
File_read::View* vshifted;
File_read::View* v = this->find_view(offset + start, size,
@@ -691,25 +682,31 @@ File_read::clear_view_cache_marks()
// the next object.
void
-File_read::clear_views(bool destroying)
+File_read::clear_views(Clear_views_mode mode)
{
+ bool keep_files_mapped = (parameters->options_valid()
+ && parameters->options().keep_files_mapped());
Views::iterator p = this->views_.begin();
while (p != this->views_.end())
{
bool should_delete;
- if (p->second->is_locked())
+ if (p->second->is_locked() || p->second->is_permanent_view())
should_delete = false;
- else if (destroying)
+ else if (mode == CLEAR_VIEWS_ALL)
should_delete = true;
- else if (p->second->should_cache())
+ else if (p->second->should_cache() && keep_files_mapped)
should_delete = false;
- else if (this->object_count_ > 1 && p->second->accessed())
+ else if (this->object_count_ > 1
+ && p->second->accessed()
+ && mode != CLEAR_VIEWS_ARCHIVE)
should_delete = false;
else
should_delete = true;
if (should_delete)
{
+ if (p->second == this->whole_file_view_)
+ this->whole_file_view_ = NULL;
delete p->second;
// map::erase invalidates only the iterator to the deleted
@@ -720,7 +717,6 @@ File_read::clear_views(bool destroying)
}
else
{
- gold_assert(!destroying);
p->second->clear_accessed();
++p;
}
@@ -736,7 +732,7 @@ File_read::clear_views(bool destroying)
}
else
{
- gold_assert(!destroying);
+ gold_assert(mode != CLEAR_VIEWS_ALL);
++q;
}
}
Index: fileread.h
===================================================================
RCS file: /cvs/src/src/gold/fileread.h,v
retrieving revision 1.42
diff -u -p -r1.42 fileread.h
--- fileread.h 24 Feb 2010 20:50:59 -0000 1.42
+++ fileread.h 10 Mar 2010 17:27:50 -0000
@@ -170,7 +170,7 @@ class File_read
// interface, and it would be nice to have something more automatic.
void
clear_uncached_views()
- { this->clear_views(false); }
+ { this->clear_views(CLEAR_VIEWS_ARCHIVE); }
// A struct used to do a multiple read.
struct Read_multiple_entry
@@ -214,6 +214,17 @@ class File_read
get_mtime();
private:
+ // Control for what views to clear.
+ enum Clear_views_mode
+ {
+ // Clear uncached views not used by an archive.
+ CLEAR_VIEWS_NORMAL,
+ // Clear all uncached views (including in an archive).
+ CLEAR_VIEWS_ARCHIVE,
+ // Clear all views (i.e., we're destroying the file).
+ CLEAR_VIEWS_ALL
+ };
+
// This class may not be copied.
File_read(const File_read&);
File_read& operator=(const File_read&);
@@ -303,6 +314,12 @@ class File_read
accessed() const
{ return this->accessed_; }
+ // Returns TRUE if this view contains permanent data -- e.g., data that
+ // was supplied by the owner of the File object.
+ bool
+ is_permanent_view() const
+ { return this->data_ownership_ == DATA_NOT_OWNED; }
+
private:
View(const View&);
View& operator=(const View&);
@@ -366,7 +383,7 @@ class File_read
// Clear the file views.
void
- clear_views(bool);
+ clear_views(Clear_views_mode);
// The size of a file page for buffering data.
static const off_t page_size = 8192;
Index: options.h
===================================================================
RCS file: /cvs/src/src/gold/options.h,v
retrieving revision 1.141
diff -u -p -r1.141 options.h
--- options.h 6 Mar 2010 02:34:13 -0000 1.141
+++ options.h 10 Mar 2010 17:27:50 -0000
@@ -774,11 +774,14 @@ class General_options
DEFINE_special(just_symbols, options::TWO_DASHES, '\0',
N_("Read only symbol values from FILE"), N_("FILE"));
- DEFINE_bool(keep_files_mapped, options::TWO_DASHES, '\0',
+ DEFINE_bool(map_whole_files, options::TWO_DASHES, '\0',
sizeof(void*) >= 8,
N_("Map whole files to memory (default on 64-bit hosts)"),
N_("Map relevant file parts to memory (default on 32-bit "
"hosts)"));
+ DEFINE_bool(keep_files_mapped, options::TWO_DASHES, '\0', true,
+ N_("Keep files mapped across passes (default)"),
+ N_("Release mapped files after each pass"));
DEFINE_special(library, options::TWO_DASHES, 'l',
N_("Search for library LIBNAME"), N_("LIBNAME"));
Index: readsyms.cc
===================================================================
RCS file: /cvs/src/src/gold/readsyms.cc,v
retrieving revision 1.40
diff -u -p -r1.40 readsyms.cc
--- readsyms.cc 12 Feb 2010 03:23:26 -0000 1.40
+++ readsyms.cc 10 Mar 2010 17:27:50 -0000
@@ -470,6 +470,8 @@ Add_symbols::run(Workqueue*)
if (!this->input_objects_->add_object(this->object_))
{
+ delete this->sd_;
+ this->sd_ = NULL;
this->object_->release();
delete this->object_;
}
@@ -477,10 +479,10 @@ Add_symbols::run(Workqueue*)
{
this->object_->layout(this->symtab_, this->layout_, this->sd_);
this->object_->add_symbols(this->symtab_, this->sd_, this->layout_);
+ delete this->sd_;
+ this->sd_ = NULL;
this->object_->release();
}
- delete this->sd_;
- this->sd_ = NULL;
}
// Class Start_group.
Index: reloc.cc
===================================================================
RCS file: /cvs/src/src/gold/reloc.cc,v
retrieving revision 1.54
diff -u -p -r1.54 reloc.cc
--- reloc.cc 12 Feb 2010 04:33:53 -0000 1.54
+++ reloc.cc 10 Mar 2010 17:27:51 -0000
@@ -179,9 +179,9 @@ void
Scan_relocs::run(Workqueue*)
{
this->object_->scan_relocs(this->symtab_, this->layout_, this->rd_);
- this->object_->release();
delete this->rd_;
this->rd_ = NULL;
+ this->object_->release();
}
// Return a debugging name for the task.
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