Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for
variable size compressed pages. Its fast and gives low fragmentation.
Following links give details on this allocator:
?- http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf
?- http://code.google.com/p/compcache/wiki/TLSFAllocator
This kernel port of TLSF (v2.3.2) introduces several changes but underlying
algorithm remains the same.
Changelog TLSF v2.3.2 vs this kernel port
?- Pool now dynamically expands/shrinks.
? ?It is collection of contiguous memory regions.
?- Changes to pool create interface as a result of above change.
?- Collect and export stats (/proc/tlsfinfo)
?- Cleanups: kernel coding style, added comments, macros -> static inline, etc.
Signed-off-by: Nitin Gupta <nitingupta910 at gmail dot com>
---
include/linux/tlsf.h | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 93 insertions(+), 0 deletions(-)
diff --git a/include/linux/tlsf.h b/include/linux/tlsf.h
new file mode 100644
index 0000000..ef8092c
--- /dev/null
+++ b/include/linux/tlsf.h
@@ -0,0 +1,93 @@
+/*
+ * Two Levels Segregate Fit memory allocator (TLSF)
+ * Version 2.3.2
+ *
+ * Written by Miguel Masmano Tello <[email protected]>
+ *
+ * Thanks to Ismael Ripoll for his suggestions and reviews
+ *
+ * Copyright (C) 2007, 2006, 2005, 2004
+ *
+ * This code is released using a dual license strategy: GPL/LGPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of the GNU General Public License Version 2.0
+ * Released under the terms of the GNU Lesser General Public License Version 2.1
+ *
+ * This is kernel port of TLSF allocator.
+ * Original code can be found at: http://rtportal.upv.es/rtmalloc/
+ * - Nitin Gupta (nitingupta910 at gmail dot com)
+ */
+
+#ifndef _TLSF_H_
+#define _TLSF_H_
+
+typedef void* (get_memory)(size_t bytes);
+typedef void (put_memory)(void *ptr);
+
+/**
+ * tlsf_create_memory_pool - create dynamic memory pool
+ * @name: name of the pool
+ * @get_mem: callback function used to expand pool
+ * @put_mem: callback function used to shrink pool
+ * @init_size: inital pool size (in bytes)
+ * @max_size: maximum pool size (in bytes) - set this as 0 for no limit
+ * @grow_size: amount of memory (in bytes) added to pool whenever required
+ *
+ * All size values are rounded up to next page boundary.
+ */
+extern void *tlsf_create_memory_pool(const char *name,
+ get_memory get_mem,
+ put_memory put_mem,
+ size_t init_size,
+ size_t max_size,
+ size_t grow_size);
+/**
+ * tlsf_destory_memory_pool - cleanup given pool
+ * @mem_pool: Pool to be destroyed
+ *
+ * Data structures associated with pool are freed.
+ * All memory allocated from pool must be freed before
+ * destorying it.
+ */
+extern void tlsf_destroy_memory_pool(void *mem_pool);
+
+/**
+ * tlsf_malloc - allocate memory from given pool
+ * @size: no. of bytes
+ * @mem_pool: pool to allocate from
+ */
+extern void *tlsf_malloc(size_t size, void *mem_pool);
+
+/**
+ * tlsf_calloc - allocate and zero-out memory from given pool
+ * @size: no. of bytes
+ * @mem_pool: pool to allocate from
+ */
+extern void *tlsf_calloc(size_t nelem, size_t elem_size, void *mem_pool);
+
+/**
+ * tlsf_free - free memory from given pool
+ * @ptr: address of memory to be freed
+ * @mem_pool: pool to free from
+ */
+extern void tlsf_free(void *ptr, void *mem_pool);
+
+/**
+ * tlsf_get_used_size - get memory currently used by given pool
+ *
+ * Used memory includes stored data + metadata + internal fragmentation
+ */
+extern size_t tlsf_get_used_size(void *mem_pool);
+
+/**
+ * tlsf_get_total_size - get total memory currently allocated for given pool
+ *
+ * This is the total memory currently allocated for this pool which includes
+ * used size + free size.
+ *
+ * (Total - Used) is good indicator of memory efficiency of allocator.
+ */
+extern size_t tlsf_get_total_size(void *mem_pool);
+
+#endif
On Mon, 2008-03-24 at 20:34 +0530, Nitin Gupta wrote:
> Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for
> variable size compressed pages. Its fast and gives low fragmentation.
> Following links give details on this allocator:
> - http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf
> - http://code.google.com/p/compcache/wiki/TLSFAllocator
>
> This kernel port of TLSF (v2.3.2) introduces several changes but underlying
> algorithm remains the same.
>
> Changelog TLSF v2.3.2 vs this kernel port
> - Pool now dynamically expands/shrinks.
> It is collection of contiguous memory regions.
> - Changes to pool create interface as a result of above change.
> - Collect and export stats (/proc/tlsfinfo)
> - Cleanups: kernel coding style, added comments, macros -> static inline, etc.
Can you explain why you need this allocator, why don't the current
kernel allocators work for you?
On Mon, Mar 24, 2008 at 10:26 PM, Peter Zijlstra <[email protected]> wrote:
> On Mon, 2008-03-24 at 20:34 +0530, Nitin Gupta wrote:
> > Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for
> > variable size compressed pages. Its fast and gives low fragmentation.
> > Following links give details on this allocator:
> > - http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf
> > - http://code.google.com/p/compcache/wiki/TLSFAllocator
> >
> > This kernel port of TLSF (v2.3.2) introduces several changes but underlying
> > algorithm remains the same.
> >
> > Changelog TLSF v2.3.2 vs this kernel port
> > - Pool now dynamically expands/shrinks.
> > It is collection of contiguous memory regions.
> > - Changes to pool create interface as a result of above change.
> > - Collect and export stats (/proc/tlsfinfo)
> > - Cleanups: kernel coding style, added comments, macros -> static inline, etc.
>
> Can you explain why you need this allocator, why don't the current
> kernel allocators work for you?
>
>
kmalloc() allocates one of pre-defined sizes (as defined in
kmalloc_sizes.h). This will surely cause severe fragmentation with
these variable sized compressed pages.
Whereas, TLSF maintains very fine grained size lists. In all the
workloads I tested, it showed <5% fragmentation. Also, its very simple
as just ~700 LOC.
- Nitin
On Mon, 2008-03-24 at 23:04 +0530, Nitin Gupta wrote:
> On Mon, Mar 24, 2008 at 10:26 PM, Peter Zijlstra <[email protected]> wrote:
> > On Mon, 2008-03-24 at 20:34 +0530, Nitin Gupta wrote:
> > > Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for
> > > variable size compressed pages. Its fast and gives low fragmentation.
> > > Following links give details on this allocator:
> > > - http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf
> > > - http://code.google.com/p/compcache/wiki/TLSFAllocator
> > >
> > > This kernel port of TLSF (v2.3.2) introduces several changes but underlying
> > > algorithm remains the same.
> > >
> > > Changelog TLSF v2.3.2 vs this kernel port
> > > - Pool now dynamically expands/shrinks.
> > > It is collection of contiguous memory regions.
> > > - Changes to pool create interface as a result of above change.
> > > - Collect and export stats (/proc/tlsfinfo)
> > > - Cleanups: kernel coding style, added comments, macros -> static inline, etc.
> >
> > Can you explain why you need this allocator, why don't the current
> > kernel allocators work for you?
> >
> >
>
> kmalloc() allocates one of pre-defined sizes (as defined in
> kmalloc_sizes.h). This will surely cause severe fragmentation with
> these variable sized compressed pages.
>
> Whereas, TLSF maintains very fine grained size lists. In all the
> workloads I tested, it showed <5% fragmentation. Also, its very simple
> as just ~700 LOC.
Yeah, it also suffers from a horrible coding style, can use excessive
amounts of vmalloc space, isn't hooked into the reclaim process as an
allocator should be and has a severe lack of per-cpu data making it a
pretty big bottleneck on anything with more than a few cores.
Now, it might be needed, might work better, and the scalability issue
might not be a problem when used for swap, but still, you don't treat
any of these points in your changelog.
FWIW, please split up the patches in a sane way. This series looks like
it wants to be 2 or 3 patches. The first introducing all of TLSF (this
split per file is horrible). The second doing all of the block device,
and a possible last doing documentation and such.
Also, how bad was kmalloc() compared to this TLSF, we need numbers :-)
On Tue, Mar 25, 2008 at 12:26 AM, Peter Zijlstra <[email protected]> wrote:
>
> On Mon, 2008-03-24 at 23:04 +0530, Nitin Gupta wrote:
> > On Mon, Mar 24, 2008 at 10:26 PM, Peter Zijlstra <[email protected]> wrote:
> > > On Mon, 2008-03-24 at 20:34 +0530, Nitin Gupta wrote:
> > > > Two Level Segregate Fit (TLSF) Allocator is used to allocate memory for
> > > > variable size compressed pages. Its fast and gives low fragmentation.
> > > > Following links give details on this allocator:
> > > > - http://rtportal.upv.es/rtmalloc/files/tlsf_paper_spe_2007.pdf
> > > > - http://code.google.com/p/compcache/wiki/TLSFAllocator
> > > >
> > > > This kernel port of TLSF (v2.3.2) introduces several changes but underlying
> > > > algorithm remains the same.
> > > >
> > > > Changelog TLSF v2.3.2 vs this kernel port
> > > > - Pool now dynamically expands/shrinks.
> > > > It is collection of contiguous memory regions.
> > > > - Changes to pool create interface as a result of above change.
> > > > - Collect and export stats (/proc/tlsfinfo)
> > > > - Cleanups: kernel coding style, added comments, macros -> static inline, etc.
> > >
> > > Can you explain why you need this allocator, why don't the current
> > > kernel allocators work for you?
> > >
> > >
> >
> > kmalloc() allocates one of pre-defined sizes (as defined in
> > kmalloc_sizes.h). This will surely cause severe fragmentation with
> > these variable sized compressed pages.
> >
> > Whereas, TLSF maintains very fine grained size lists. In all the
> > workloads I tested, it showed <5% fragmentation. Also, its very simple
> > as just ~700 LOC.
>
> Yeah, it also suffers from a horrible coding style, can use excessive
> amounts of vmalloc space, isn't hooked into the reclaim process as an
> allocator should be and has a severe lack of per-cpu data making it a
> pretty big bottleneck on anything with more than a few cores.
>
> Now, it might be needed, might work better, and the scalability issue
> might not be a problem when used for swap, but still, you don't treat
> any of these points in your changelog.
Currently, this TLSF implementation is not scalable at all (and thats
why it depends on EMBEDDED).
>
> FWIW, please split up the patches in a sane way. This series looks like
> it wants to be 2 or 3 patches. The first introducing all of TLSF (this
> split per file is horrible). The second doing all of the block device,
> and a possible last doing documentation and such.
>
> Also, how bad was kmalloc() compared to this TLSF, we need numbers :-)
>
>
Ok, I will get them and present here.
Thanks,
Nitin