incubator-nuttx/mm/tlsf/0003-Support-customize-FL_I...

96 lines
3.0 KiB
Diff

From d2d18a9ed8836dac252f7c4c61541c2a9e4ebbf0 Mon Sep 17 00:00:00 2001
From: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Wed, 10 Mar 2021 02:30:33 +0800
Subject: [PATCH 3/8] Support customize FL_INDEX_MAX to reduce the memory
overhead
user can define the max pool size through TLSF_MAX_POOL_SIZE
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: I021b816f65c1bc5c1025969bc6cc458029f3bc88
---
tlsf.c | 46 +++++++++++++++++++++++++++++-----------------
1 file changed, 29 insertions(+), 17 deletions(-)
diff --git a/tlsf.c tlsf/tlsf/tlsf.c
index ea8d640..66daf33 100644
--- a/tlsf.c
+++ tlsf/tlsf/tlsf.c
@@ -48,6 +48,29 @@
#define TLSF_64BIT
#endif
+/*
+** Returns one plus the index of the most significant 1-bit of n,
+** or if n is zero, returns zero.
+*/
+#ifdef TLSF_64BIT
+#define TLSF_FLS(n) ((n) & 0xffffffff00000000ull ? 32 + TLSF_FLS32((size_t)(n) >> 32) : TLSF_FLS32(n))
+#else
+#define TLSF_FLS(n) TLSF_FLS32(n)
+#endif
+
+#define TLSF_FLS32(n) ((n) & 0xffff0000 ? 16 + TLSF_FLS16((n) >> 16) : TLSF_FLS16(n))
+#define TLSF_FLS16(n) ((n) & 0xff00 ? 8 + TLSF_FLS8 ((n) >> 8) : TLSF_FLS8 (n))
+#define TLSF_FLS8(n) ((n) & 0xf0 ? 4 + TLSF_FLS4 ((n) >> 4) : TLSF_FLS4 (n))
+#define TLSF_FLS4(n) ((n) & 0xc ? 2 + TLSF_FLS2 ((n) >> 2) : TLSF_FLS2 (n))
+#define TLSF_FLS2(n) ((n) & 0x2 ? 1 + TLSF_FLS1 ((n) >> 1) : TLSF_FLS1 (n))
+#define TLSF_FLS1(n) ((n) & 0x1 ? 1 : 0)
+
+/*
+** Returns round up value of log2(n).
+** Note: it is used at compile time.
+*/
+#define TLSF_LOG2_CEIL(n) ((n) & (n - 1) ? TLSF_FLS(n) : TLSF_FLS(n) - 1)
+
/*
** gcc 3.4 and above have builtin support, specialized for architecture.
** Some compilers masquerade as gcc; patchlevel test filters them out.
@@ -155,29 +178,16 @@ tlsf_decl int tlsf_fls(unsigned int word)
#else
/* Fall back to generic implementation. */
-tlsf_decl int tlsf_fls_generic(unsigned int word)
-{
- int bit = 32;
-
- if (!word) bit -= 1;
- if (!(word & 0xffff0000)) { word <<= 16; bit -= 16; }
- if (!(word & 0xff000000)) { word <<= 8; bit -= 8; }
- if (!(word & 0xf0000000)) { word <<= 4; bit -= 4; }
- if (!(word & 0xc0000000)) { word <<= 2; bit -= 2; }
- if (!(word & 0x80000000)) { word <<= 1; bit -= 1; }
-
- return bit;
-}
-
/* Implement ffs in terms of fls. */
tlsf_decl int tlsf_ffs(unsigned int word)
{
- return tlsf_fls_generic(word & (~word + 1)) - 1;
+ const unsigned int reverse = word & (~word + 1);
+ return TLSF_FLS32(reverse) - 1;
}
tlsf_decl int tlsf_fls(unsigned int word)
{
- return tlsf_fls_generic(word) - 1;
+ return TLSF_FLS32(word) - 1;
}
#endif
@@ -242,7 +252,9 @@ enum tlsf_private
** blocks below that size into the 0th first-level list.
*/
-#if defined (TLSF_64BIT)
+#if defined (TLSF_MAX_POOL_SIZE)
+ FL_INDEX_MAX = TLSF_LOG2_CEIL(TLSF_MAX_POOL_SIZE),
+#elif defined (TLSF_64BIT)
/*
** TODO: We can increase this to support larger sizes, at the expense
** of more overhead in the TLSF structure.
--
2.34.1