In-depth: The New MorphOS Memory System - Revision history

ASiegel at 20:17, 3 December 2009

2009-12-03T20:17:37Z

ASiegel at 20:16, 3 December 2009

2009-12-03T20:16:17Z

ASiegel at 10:04, 2 December 2009

2009-12-02T10:04:32Z

ASiegel at 10:04, 2 December 2009

2009-12-02T10:04:07Z

ASiegel at 09:48, 2 December 2009

2009-12-02T09:48:45Z

ASiegel at 09:48, 2 December 2009

2009-12-02T09:48:14Z

ASiegel at 09:45, 2 December 2009

2009-12-02T09:45:57Z

ASiegel at 09:44, 2 December 2009

2009-12-02T09:44:38Z

ASiegel at 09:44, 2 December 2009

2009-12-02T09:44:23Z

ASiegel at 09:43, 2 December 2009

2009-12-02T09:43:57Z

← Older revision		Revision as of 20:17, 3 December 2009
Line 81:		Line 81:


−	==2. Reducing Effects of Fragmentation==	+	==Reducing Effects of Fragmentation==

	Fragmentation happens, there is no way around it. Over time the memory will fragment. The trick is to reduce the adverse effect it has on system performance.		Fragmentation happens, there is no way around it. Over time the memory will fragment. The trick is to reduce the adverse effect it has on system performance.

@@ Line 6: / Line 6: @@
-'''0. Foreword'''
+==Foreword==
 Many parts of AmigaOS were designed 25 years ago. At the time system resources were scarce and processors were relatively slow.
@@ Line 22: / Line 22: @@
-'''1. Compatibility'''
+==Compatibility==
 The first requirement was clearly the most critical one as MorphOS traditionally wants to maintain as much compatibility as possible, while introducing new advanced things, too.
@@ Line 81: / Line 81: @@
-'''2. Reducing Effects of Fragmentation'''
+==2. Reducing Effects of Fragmentation==
 Fragmentation happens, there is no way around it. Over time the memory will fragment. The trick is to reduce the adverse effect it has on system performance.
@@ Line 91: / Line 91: @@
-'''3. Reducing Memory Fragmentation'''
+==Reducing Memory Fragmentation==
 The choice of algorithm is critical here, as well. For example the original First Fit algorithm generates a lot of fragmentation over time. To give fast allocation speeds it returns the first memory block fitting the requirements.
@@ Line 101: / Line 101: @@
-'''4. Implementation'''
+==Implementation==
 MorphOS 2.0 and later has a pluggable memory interface. Basically different allocator schemes can be selected at boot time. For now the possible options are First Fit (same as in AmigaOS and MorphOS 1.x) and Two Level Segregated Fit (default). The user can configure the desired memory system by adjusting the MorphOS boot command in OpenFirmware.
@@ Line 122: / Line 122: @@
 ----
-'''5. References'''
+==References==
 http://rtportal.upv.es/rtmalloc/files/ecrts04_tlsf.pdf
 http://en.wikipedia.org/wiki/Dynamic_memory_allocation

@@ Line 51: / Line 51: @@
 Another example is a routine which allocates the largest memory block:
-<code>void *alloclargest(ULONG flags)
+<pre>void *alloclargest(ULONG flags)
+{
    ULONG largest;
@@ Line 60: / Line 60: @@
    Permit();
    return ptr;
-}</code>
+}</pre>

@@ Line 30: / Line 30: @@
 The challenge was to introduce a faster memory system without breaking these functions. For example there is a common code sequence to obtain aligned memory blocks:
-<code>void *allocaligned(ULONG size, ULONG flags, ULONG align)
+<pre>void *allocaligned(ULONG size, ULONG flags, ULONG align)
+{
    void *ptr = AllocMem(size + align - 1, flags & ~MEMF_CLEAR);
@@ Line 44: / Line 44: @@
+   }
    return ptr;
-}</code>
+}</pre>

← Older revision		Revision as of 09:48, 2 December 2009
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	http://rtportal.upv.es/rtmalloc/files/ecrts04_tlsf.pdf		http://rtportal.upv.es/rtmalloc/files/ecrts04_tlsf.pdf
		+
	http://en.wikipedia.org/wiki/Dynamic_memory_allocation		http://en.wikipedia.org/wiki/Dynamic_memory_allocation

← Older revision		Revision as of 09:48, 2 December 2009
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	''Author: Harry Sintonen''		''Author: Harry Sintonen''
		+
		+	----


Line 117:		Line 119:

	The TLSF memory system fills all the design goals: It is very compatible with even the oldest applications. It maintains good performance regardless of the memory fragmentation. It reduces memory fragmentation.		The TLSF memory system fills all the design goals: It is very compatible with even the oldest applications. It maintains good performance regardless of the memory fragmentation. It reduces memory fragmentation.
		+
		+
		+	----
		+	'''5. References'''
		+
		+	http://rtportal.upv.es/rtmalloc/files/ecrts04_tlsf.pdf
		+	http://en.wikipedia.org/wiki/Dynamic_memory_allocation

← Older revision		Revision as of 09:44, 2 December 2009
Line 1:		Line 1:
	''Originally published at: http://morphos-team.net/tlsf.html''		''Originally published at: http://morphos-team.net/tlsf.html''
		+
	''Author: Harry Sintonen''		''Author: Harry Sintonen''