[PATCH v4 0/2] mm: Better handling of adding new regions

[Zhang Boyang]

Hi,

Changes in V3 -> V4:

* [PATCH v4 1/2] mm: Try invalidate disk caches last when out of memory
  Added "Reviewed-by" tags.

* [PATCH v4 2/2] mm: Better handling of adding new regions
  Made this patch standalone.
  Moved (and renamed back) new constants to "mm_private.h" from "mm.h".
  Documented more details in comments.

* The allocation type patch will be posted later.

Best Regards,
Zhang Boyang

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Changes in V2 -> V3:

1. Splited into two patches. One deal with the disk cache problem. The
other is focused on improvement.
2. Add types to regions. So small and large allocations are effectively
seperated into different heaps. This facility can also seperate module
segments and plain data chunks.
3. Region management costs are now denoted by GRUB_MM_MAX_COST,
seperated from GRUB_MM_GROW_SMALL ( =GRUB_MM_HEAP_GROW in previous
patch).

Some notes for the size of heap growth:

In order to guarantee the success of allocation when heap exhausted, the
new region size should be at least (size + align + GRUB_MM_MAX_COST).
For small chunks, it's adjusted to (GRUB_MM_GROW_SMALL +
GRUB_MM_MAX_COST) to improve performance.