Commit d602daba authored Jul 10, 2010 by Bob Liu Committed by Pekka Enberg Jul 16, 2010

SLOB: Free objects to their own list



SLOB has alloced smaller objects from their own list in reduce overall external
fragmentation and increase repeatability, free to their own list also.

This is /proc/meminfo result in my test machine:

  without this patch:
  ===
  MemTotal:        1030720 kB
  MemFree:          750012 kB
  Buffers:           15496 kB
  Cached:           160396 kB
  SwapCached:            0 kB
  Active:           105024 kB
  Inactive:         145604 kB
  Active(anon):      74816 kB
  Inactive(anon):     2180 kB
  Active(file):      30208 kB
  Inactive(file):   143424 kB
  Unevictable:          16 kB
  ....

  with this patch:
  ===
  MemTotal:        1030720 kB
  MemFree:          751908 kB
  Buffers:           15492 kB
  Cached:           160280 kB
  SwapCached:            0 kB
  Active:           102720 kB
  Inactive:         146140 kB
  Active(anon):      73168 kB
  Inactive(anon):     2180 kB
  Active(file):      29552 kB
  Inactive(file):   143960 kB
  Unevictable:          16 kB
  ...

The result shows an improvement of 1 MB!

And when I tested it on a embeded system with 64 MB, I found this path is never
called during kernel bootup.

Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

parent 1c5474a6

mm/slob.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -394,6 +394,7 @@ static void slob_free(void *block, int size)
		slob_t prev, next, b = (slob_t )block;
		slobidx_t units;
		unsigned long flags;
		struct list_head *slob_list;

		if (unlikely(ZERO_OR_NULL_PTR(block)))
		return;
		@@ -422,7 +423,13 @@ static void slob_free(void *block, int size)
		set_slob(b, units,
		(void *)((unsigned long)(b +
		SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
		set_slob_page_free(sp, &free_slob_small);
		if (size < SLOB_BREAK1)
		slob_list = &free_slob_small;
		else if (size < SLOB_BREAK2)
		slob_list = &free_slob_medium;
		else
		slob_list = &free_slob_large;
		set_slob_page_free(sp, slob_list);
		goto out;
		}

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