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changeset 14020:3843f7c5f635

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3705 stack overflow due to zfs lz4 compression Reviewed by: Matthew Ahrens <mahrens@delphix.com> Approved by: Christopher Siden <christopher.siden@delphix.com>
author Sašo Kiselkov <skiselkov.ml@gmail.com>
date Wed, 24 Apr 2013 08:45:43 -0800
parents 624fa8f61951
children 1faa5bdf272f
files usr/src/uts/common/fs/zfs/lz4.c
diffstat 1 files changed, 8 insertions(+), 15 deletions(-) [+]
line wrap: on
line diff
--- a/usr/src/uts/common/fs/zfs/lz4.c	Tue Apr 23 09:31:42 2013 -0800
+++ b/usr/src/uts/common/fs/zfs/lz4.c	Wed Apr 24 08:45:43 2013 -0800
@@ -197,20 +197,17 @@
     defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || \
     defined(__LP64__) || defined(_LP64))
 #define	LZ4_ARCH64 1
-/*
- * Illumos: On amd64 we have 20k of stack and 24k on sun4u and sun4v, so we
- * can spend 16k on the algorithm
- */
-#define	STACKLIMIT 12
 #else
 #define	LZ4_ARCH64 0
+#endif
+
 /*
- * Illumos: On i386 we only have 12k of stack, so in order to maintain the
- * same COMPRESSIONLEVEL we have to use heap allocation. Performance will
- * suck, but alas, it's ZFS on 32-bit we're talking about, so...
+ * Limits the amount of stack space that the algorithm may consume to hold
+ * the compression lookup table. The value `9' here means we'll never use
+ * more than 2k of stack (see above for a description of COMPRESSIONLEVEL).
+ * If more memory is needed, it is allocated from the heap.
  */
-#define	STACKLIMIT 11
-#endif
+#define	STACKLIMIT 9
 
 /*
  * Little Endian or Big Endian?
@@ -240,11 +237,7 @@
 #define	LZ4_FORCE_UNALIGNED_ACCESS 1
 #endif
 
-/*
- * Illumos: we can't use GCC's __builtin_ctz family of builtins in the
- * kernel
- */
-#define	LZ4_FORCE_SW_BITCOUNT
+/* #define	LZ4_FORCE_SW_BITCOUNT */
 
 /*
  * Compiler Options