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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/20211004142829.22222-2-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Ping Fang <pifang@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Uladzislau Rezki (Sony) 2021-11-05 13:39:34 -07:00 committed by Linus Torvalds
parent 9f531973df
commit 066fed59d8
1 changed files with 4 additions and 4 deletions
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8
mm/vmalloc.c
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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;