[git] CMU Common Lisp branch master updated. snapshot-2013-04-7-gb76e597
Raymond Toy
rtoy at common-lisp.net
Sat Apr 27 16:08:25 UTC 2013
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- Log -----------------------------------------------------------------
commit b76e59723e21a2c494948dcc4be940e5d7e802ec
Author: Raymond Toy <toy.raymond at gmail.com>
Date: Sat Apr 27 09:08:11 2013 -0700
Clean up madvise implementation
* Remove PAGE_MADVISE_MASK
* Remove code using PAGE_MADVISE_MASK
* Move some #defines from gencgc.c to gencgc.h
* Add new or better comments
diff --git a/src/lisp/gencgc.c b/src/lisp/gencgc.c
index 2f7ecf1..fb4a741 100644
--- a/src/lisp/gencgc.c
+++ b/src/lisp/gencgc.c
@@ -288,34 +288,43 @@ boolean verify_dynamic_code_check = FALSE;
boolean check_code_fixups = FALSE;
-/* How have a page zero-filled. */
+/*
+ * How to have a page zero-filled. When a page is freed, we need to
+ * either zero it immediately or mark it as needing to be zero-filled
+ * when it is allocated later.
+ */
enum gencgc_unmap_mode {
- /* Unmap and mmap the region to get it zeroed */
+ /*
+ * Unmap and mmap the region to get it zeroed when the page
+ * is freed..
+ */
MODE_MAP,
- /* Memset the region to 0 */
+ /*
+ * Memset the region to 0 when it is freed.
+ */
MODE_MEMSET,
/*
* Call madvise to allow the kernel to free the memory if needed.
- * But when the region needs to be used, we will zero it if
- * necessary
+ * But when the region needs to be allocated, we will zero it if
+ * necessary.
*/
MODE_MADVISE,
/*
* Like madvise, except we don't actually call madvize and lazily
- * zero the region when needed.
+ * zero the region when it is allocated.
*/
MODE_LAZY,
};
/*
- * Control how freed regions should be zeroed. Default to MODE_MEMSET
+ * Control how freed regions should be zeroed. Default to MODE_LAZY
* for all systems since tests indicate that it is much faster than
* unmapping and re-mapping it to zero the region. See enum
- * gencgc_unmap_made for other ossible options.
+ * gencgc_unmap_made for other possible options.
*
* XXX: Choose the appopriate mode for each OS/arch.
*
@@ -352,13 +361,13 @@ boolean gencgc_zero_check_during_free_heap = FALSE;
#endif
/*
- * For now, enable the gencgc_zero_check if gencgc_unmap_zero is lazy.
- * XXX: Remove this additional condition when we feel that
- * gencgc_unmap_zero is good enough.
+ * For now, enable the gencgc_zero_check if gencgc_unmap_zero is lazy
+ * or madvise. XXX: Remove this additional condition when we feel
+ * that gencgc_unmap_zero is good enough.
*/
-#define DO_GENCGC_ZERO_CHECK (gencgc_zero_check || (gencgc_unmap_zero == MODE_LAZY))
-#define DO_GENCGC_ZERO_CHECK_DURING_FREE_HEAP (gencgc_zero_check_during_free_heap || (gencgc_unmap_zero == MODE_LAZY))
+#define DO_GENCGC_ZERO_CHECK (gencgc_zero_check || (gencgc_unmap_zero == MODE_LAZY) || (gencgc_unmap_zero == MODE_MADVISE))
+#define DO_GENCGC_ZERO_CHECK_DURING_FREE_HEAP (gencgc_zero_check_during_free_heap || (gencgc_unmap_zero == MODE_LAZY) || (gencgc_unmap_zero == MODE_MADVISE))
/*
* The minimum size for a large object.
@@ -954,7 +963,7 @@ handle_heap_overflow(const char *msg, int size)
}
/*
- * Enable debug messages for MODE_MADVISE and MODE_LAZY
+ * Enables debug messages for MODE_MADVISE and MODE_LAZY
*/
boolean gencgc_debug_madvise = FALSE;
@@ -968,11 +977,7 @@ handle_madvise_first_page(int first_page)
first_page, flags, page_table[first_page].bytes_used);
}
-#if 0
- if ((flags & PAGE_MADVISE_MASK) && !PAGE_ALLOCATED(first_page)) {
-#else
if (!PAGE_ALLOCATED(first_page)) {
-#endif
int *page_start = (int *) page_address(first_page);
if (gencgc_debug_madvise) {
@@ -980,10 +985,6 @@ handle_madvise_first_page(int first_page)
}
if (*page_start != 0) {
memset(page_start, 0, GC_PAGE_SIZE);
-#if 0
- page_table[first_page].flags &= ~PAGE_MADVISE_MASK;
-#else
-#endif
}
}
if (gencgc_debug_madvise) {
@@ -997,11 +998,7 @@ handle_madvise_other_pages(int first_page, int last_page)
int i;
for (i = first_page + 1; i <= last_page; ++i) {
-#if 0
- if (page_table[i].flags & PAGE_MADVISE_MASK) {
-#else
- if (!PAGE_ALLOCATED(i)) {
-#endif
+ if (!PAGE_ALLOCATED(i)) {
int *page_start = (int *) page_address(i);
if (gencgc_debug_madvise) {
@@ -1010,9 +1007,6 @@ handle_madvise_other_pages(int first_page, int last_page)
}
if (*page_start != 0) {
memset(page_start, 0, GC_PAGE_SIZE);
-#if 0
- page_table[i].flags &= ~PAGE_MADVISE_MASK;
-#endif
}
}
}
@@ -6995,19 +6989,12 @@ free_oldspace(void)
fprintf(stderr, "ADVISING pages %d-%d\n", first_page, last_page - 1);
}
-#if defined(__linux__)
-#define GENCGC_MADVISE MADV_DONTNEED
-#else
-#define GENCGC_MADVISE MADV_FREE
-#endif
-
page_start = (int *) page_address(first_page);
madvise(page_start, GC_PAGE_SIZE * (last_page - first_page), GENCGC_MADVISE);
for (page = first_page; page < last_page; ++page) {
- page_table[page].flags |= PAGE_MADVISE_MASK;
page_start = (int *) page_address(page);
- *page_start = 0xdead0000;
+ *page_start = PAGE_NEEDS_ZEROING_MARKER;
}
break;
@@ -7028,7 +7015,7 @@ free_oldspace(void)
}
page_start = (int *) page_address(page);
- *page_start = 0xdead0000;
+ *page_start = PAGE_NEEDS_ZEROING_MARKER;
}
break;
diff --git a/src/lisp/gencgc.h b/src/lisp/gencgc.h
index ce1bf07..a7ce03a 100644
--- a/src/lisp/gencgc.h
+++ b/src/lisp/gencgc.h
@@ -19,6 +19,23 @@ int gc_write_barrier(void *);
/*
+ * How to madvise pages, if enabled
+ */
+#if defined(__linux__)
+#define GENCGC_MADVISE MADV_DONTNEED
+#else
+#define GENCGC_MADVISE MADV_FREE
+#endif
+
+/*
+ * That start of each unallocate page is set to this value to indicate
+ * that the page needs to be zeroed before being allocated. This is
+ * used when gencgc_unmap_zero is MODE_MADVISE or MODE_LAZY. Any
+ * non-zero value will work.
+ */
+#define PAGE_NEEDS_ZEROING_MARKER 0xdead0000
+
+/*
* Set when the page is write protected. If it is writen into it is
* made writable and this flag is cleared. This should always reflect
* the actual write_protect status of a page.
@@ -77,8 +94,6 @@ int gc_write_barrier(void *);
#define PAGE_LARGE_OBJECT_VAL(page) \
(PAGE_LARGE_OBJECT(page) >> PAGE_LARGE_OBJECT_SHIFT)
-#define PAGE_MADVISE_MASK 0x00000400
-
/*
* The generation that this page belongs to. This should be valid for
* all pages that may have objects allocated, even current allocation
-----------------------------------------------------------------------
Summary of changes:
src/lisp/gencgc.c | 65 +++++++++++++++++++++--------------------------------
src/lisp/gencgc.h | 19 ++++++++++++++--
2 files changed, 43 insertions(+), 41 deletions(-)
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