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| author | Yue Hu <huyue2@yulong.com> | 2019-05-14 03:17:41 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-15 12:54:51 +0300 |
| commit | 20fbb34e22daf0a039349e04a2c8c5d327f3b6a3 (patch) | |
| tree | fcc079bd31865927a57f6089b987ef33e58edcfd /mm/cma.c | |
| parent | f3da1dc887bc3ab84e60486cd05fcdbb39f8ba01 (diff) | |
| download | linux-20fbb34e22daf0a039349e04a2c8c5d327f3b6a3.tar.xz | |
mm/cma.c: fix the bitmap status to show failed allocation reason
[ Upstream commit 2b59e01a3aa665f751d1410b99fae9336bd424e1 ]
Currently one bit in cma bitmap represents number of pages rather than
one page, cma->count means cma size in pages. So to find available pages
via find_next_zero_bit()/find_next_bit() we should use cma size not in
pages but in bits although current free pages number is correct due to
zero value of order_per_bit. Once order_per_bit is changed the bitmap
status will be incorrect.
The size input in cma_debug_show_areas() is not correct. It will
affect the available pages at some position to debug the failure issue.
This is an example with order_per_bit = 1
Before this change:
[ 4.120060] cma: number of available pages: 1@93+4@108+7@121+7@137+7@153+7@169+7@185+7@201+3@213+3@221+3@229+3@237+3@245+3@253+3@261+3@269+3@277+3@285+3@293+3@301+3@309+3@317+3@325+19@333+15@369+512@512=> 638 free of 1024 total pages
After this change:
[ 4.143234] cma: number of available pages: 2@93+8@108+14@121+14@137+14@153+14@169+14@185+14@201+6@213+6@221+6@229+6@237+6@245+6@253+6@261+6@269+6@277+6@285+6@293+6@301+6@309+6@317+6@325+38@333+30@369=> 252 free of 1024 total pages
Obviously the bitmap status before is incorrect.
Link: http://lkml.kernel.org/r/20190320060829.9144-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Laura Abbott <labbott@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm/cma.c')
| -rw-r--r-- | mm/cma.c | 19 |
1 files changed, 11 insertions, 8 deletions
@@ -366,23 +366,26 @@ err: #ifdef CONFIG_CMA_DEBUG static void cma_debug_show_areas(struct cma *cma) { - unsigned long next_zero_bit, next_set_bit; + unsigned long next_zero_bit, next_set_bit, nr_zero; unsigned long start = 0; - unsigned int nr_zero, nr_total = 0; + unsigned long nr_part, nr_total = 0; + unsigned long nbits = cma_bitmap_maxno(cma); mutex_lock(&cma->lock); pr_info("number of available pages: "); for (;;) { - next_zero_bit = find_next_zero_bit(cma->bitmap, cma->count, start); - if (next_zero_bit >= cma->count) + next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start); + if (next_zero_bit >= nbits) break; - next_set_bit = find_next_bit(cma->bitmap, cma->count, next_zero_bit); + next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit); nr_zero = next_set_bit - next_zero_bit; - pr_cont("%s%u@%lu", nr_total ? "+" : "", nr_zero, next_zero_bit); - nr_total += nr_zero; + nr_part = nr_zero << cma->order_per_bit; + pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part, + next_zero_bit); + nr_total += nr_part; start = next_zero_bit + nr_zero; } - pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count); + pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count); mutex_unlock(&cma->lock); } #else |