The patch titled
flex_array: add flex_array_shrink function
has been added to the -mm tree. Its filename is
flex_array-add-flex_array_shrink-function.patch
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------------------------------------------------------
Subject: flex_array: add flex_array_shrink function
From: David Rientjes <rientjes@xxxxxxxxxx>
Add a new function to the flex_array API:
int flex_array_shrink(struct flex_array *fa)
This function will free all unused second-level pages. Since elements are
now poisoned if they are not allocated with __GFP_ZERO, it's possible to
identify parts that consist solely of unused elements.
flex_array_shrink() returns the number of pages freed.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/flex_array.h | 1
lib/flex_array.c | 40 +++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff -puN include/linux/flex_array.h~flex_array-add-flex_array_shrink-function include/linux/flex_array.h
--- a/include/linux/flex_array.h~flex_array-add-flex_array_shrink-function
+++ a/include/linux/flex_array.h
@@ -46,5 +46,6 @@ int flex_array_put(struct flex_array *fa
gfp_t flags);
int flex_array_clear(struct flex_array *fa, unsigned int element_nr);
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);
+int flex_array_shrink(struct flex_array *fa);
#endif /* _FLEX_ARRAY_H */
diff -puN lib/flex_array.c~flex_array-add-flex_array_shrink-function lib/flex_array.c
--- a/lib/flex_array.c~flex_array-add-flex_array_shrink-function
+++ a/lib/flex_array.c
@@ -291,3 +291,43 @@ void *flex_array_get(struct flex_array *
}
return &part->elements[index_inside_part(fa, element_nr)];
}
+
+static int part_is_free(struct flex_array_part *part)
+{
+ int i;
+
+ for (i = 0; i < sizeof(struct flex_array_part); i++)
+ if (part->elements[i] != FLEX_ARRAY_FREE)
+ return 0;
+ return 1;
+}
+
+/**
+ * flex_array_shrink - free unused second-level pages
+ *
+ * Frees all second-level pages that consist solely of unused
+ * elements. Returns the number of pages freed.
+ *
+ * Locking must be provided by the caller.
+ */
+int flex_array_shrink(struct flex_array *fa)
+{
+ struct flex_array_part *part;
+ int max_part = nr_base_part_ptrs();
+ int part_nr;
+ int ret = 0;
+
+ if (elements_fit_in_base(fa))
+ return ret;
+ for (part_nr = 0; part_nr < max_part; part_nr++) {
+ part = fa->parts[part_nr];
+ if (!part)
+ continue;
+ if (part_is_free(part)) {
+ fa->parts[part_nr] = NULL;
+ kfree(part);
+ ret++;
+ }
+ }
+ return ret;
+}
_
Patches currently in -mm which might be from rientjes@xxxxxxxxxx are
origin.patch
linux-next.patch
flex_array-fix-get-function-for-elements-in-base-starting-at-non-zero.patch
flex_array-fix-flex_array_free_parts-comment.patch
flex_array-declare-parts-member-to-have-incomplete-type.patch
flex_array-convert-element_nr-formals-to-unsigned.patch
flex_array-add-flex_array_clear-function.patch
flex_array-poison-free-elements.patch
flex_array-add-flex_array_shrink-function.patch
mm-remove-obsoleted-alloc_pages-cpuset-comment.patch
hugetlb-balance-freeing-of-huge-pages-across-nodes.patch
hugetlb-use-free_pool_huge_page-to-return-unused-surplus-pages.patch
hugetlb-use-free_pool_huge_page-to-return-unused-surplus-pages-fix.patch
hugetlb-clean-up-and-update-huge-pages-documentation.patch
mm-oom-analysis-add-per-zone-statistics-to-show_free_areas.patch
mm-oom-analysis-add-buffer-cache-information-to-show_free_areas.patch
mm-oom-analysis-show-kernel-stack-usage-in-proc-meminfo-and-oom-log-output.patch
mm-oom-analysis-add-shmem-vmstat.patch
mm-update-alloc_flags-after-oom-killer-has-been-called.patch
pagemap-clear_refs-modify-to-specify-anon-or-mapped-vma-clearing.patch
oom-move-oom_killer_enable-oom_killer_disable-to-where-they-belong.patch
fs-proc-task_mmuc-v1-fix-clear_refs_write-input-sanity-check.patch
do_wait-optimization-do-not-place-sub-threads-on-task_struct-children-list.patch
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