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authorJoel Sherrill <joel.sherrill@OARcorp.com>2000-02-11 15:54:47 +0000
committerJoel Sherrill <joel.sherrill@OARcorp.com>2000-02-11 15:54:47 +0000
commit562e7ed1ed282d9e6ecc50a228359bf35e5adec5 (patch)
tree4141461be9035f4ffd640351af771a7c0ac8f330 /c/src/lib/libc
parentPatch from Eric Norum <eric@cls.usask.ca> based on working with (diff)
downloadrtems-562e7ed1ed282d9e6ecc50a228359bf35e5adec5.tar.bz2
Increased block size to 128 and added comments based on feedback from
Java folks including Oscar Martinez de la Torre <omt@wm.estec.esa.nl>.
Diffstat (limited to 'c/src/lib/libc')
-rw-r--r--c/src/lib/libc/imfs.h14
1 files changed, 13 insertions, 1 deletions
diff --git a/c/src/lib/libc/imfs.h b/c/src/lib/libc/imfs.h
index 585c070594..38c770a325 100644
--- a/c/src/lib/libc/imfs.h
+++ b/c/src/lib/libc/imfs.h
@@ -66,9 +66,21 @@ typedef struct {
*
* block_ptr is a pointer to a block of IMFS_MEMFILE_BYTES_PER_BLOCK in
* length which could be data or a table of pointers to blocks.
+ *
+ * Setting IMFS_MEMFILE_BYTES_PER_BLOCK to different values has a significant
+ * impact on the maximum file size supported as well as the amount of
+ * memory wasted due to internal file fragmentation. The following
+ * is a list of maximum file sizes based on various settings
+ *
+ * max_filesize with blocks of 16 is 1,328
+ * max_filesize with blocks of 32 is 18,656
+ * max_filesize with blocks of 64 is 279,488
+ * max_filesize with blocks of 128 is 4,329,344
+ * max_filesize with blocks of 256 is 68,173,568
+ * max_filesize with blocks of 512 is 1,082,195,456
*/
-#define IMFS_MEMFILE_BYTES_PER_BLOCK 64 /* 512 */
+#define IMFS_MEMFILE_BYTES_PER_BLOCK 128
#define IMFS_MEMFILE_BLOCK_SLOTS \
(IMFS_MEMFILE_BYTES_PER_BLOCK / sizeof(void *))