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mm/vmalloc: check various alignments when debugging

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Before we did not guarantee a free block with lowest start address for
allocations with alignment >= PAGE_SIZE.  Because an alignment overhead
was included into a search length like below:

     length = size + align - 1;

doing so we make sure that a bigger block would fit after applying an
alignment adjustment.  Now there is no such limitation, i.e.  any
alignment that user wants to apply will result to a lowest address of
returned free area.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Oleksiy Avramchenko <[email protected]>
Cc: Ping Fang <[email protected]>
Cc: Steven Rostedt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Uladzislau Rezki (Sony) authored and Linus Torvalds committed 2021-11-06 13:30:37 -07:00
1 parent 9f531973df
commit 066fed59d8
1 file changed
+4 -4
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mm/vmalloc.c
+4 -4
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@@ -1269,7 +1269,7 @@ find_vmap_lowest_linear_match(unsigned long size,
}
static void
find_vmap_lowest_match_check(unsigned long size)
find_vmap_lowest_match_check(unsigned long size, unsigned long align)
{
struct vmap_area *va_1, *va_2;
unsigned long vstart;
@@ -1278,8 +1278,8 @@ find_vmap_lowest_match_check(unsigned long size)
get_random_bytes(&rnd, sizeof(rnd));
vstart = VMALLOC_START + rnd;
va_1 = find_vmap_lowest_match(size, 1, vstart);
va_2 = find_vmap_lowest_linear_match(size, 1, vstart);
va_1 = find_vmap_lowest_match(size, align, vstart);
va_2 = find_vmap_lowest_linear_match(size, align, vstart);
if (va_1 != va_2)
pr_emerg("not lowest: t: 0x%p, l: 0x%p, v: 0x%lx\n",
@@ -1458,7 +1458,7 @@ __alloc_vmap_area(unsigned long size, unsigned long align,
return vend;
#if DEBUG_AUGMENT_LOWEST_MATCH_CHECK
find_vmap_lowest_match_check(size);
find_vmap_lowest_match_check(size, align);
#endif
return nva_start_addr;