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| author | Sergey SENOZHATSKY <sergey.senozhatsky@gmail.com> | 2015-11-07 00:29:04 (GMT) |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-07 01:50:42 (GMT) |
| commit | 1237275580f3e2b998d355b2ff7f84c6b423aa11 (patch) | |
| tree | 24b055730587c8643d1c136a4a7d89d25e675dba | |
| parent | 1d5b43bfb60f7ba2b51792978a6b0781d4ebba93 (diff) | |
| download | linux-1237275580f3e2b998d355b2ff7f84c6b423aa11.tar.xz | |
zram: keep the exact overcommited value in mem_used_max
`mem_used_max' is designed to store the max amount of memory zram consumed
to store the data. However, it does not represent the actual
'overcommited' (max) value. The existing code goes to -ENOMEM
overcommited case before it updates `->stats.max_used_pages', which hides
the reason we went to -ENOMEM in the first place -- we actually used more
memory than `->limit_pages':
alloced_pages = zs_get_total_pages(meta->mem_pool);
if (zram->limit_pages && alloced_pages > zram->limit_pages) {
zs_free(meta->mem_pool, handle);
ret = -ENOMEM;
goto out;
}
update_used_max(zram, alloced_pages);
Which is misleading. User will see -ENOMEM, check `->limit_pages', check
`->stats.max_used_pages', which will keep the value BEFORE zram passed
`->limit_pages', and see:
`->stats.max_used_pages' < `->limit_pages'
Move update_used_max() before we do `->limit_pages' check, so that
user will see:
`->stats.max_used_pages' > `->limit_pages'
should the overcommit and -ENOMEM happen.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index c93aeb8..3e8d8ff 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -726,14 +726,14 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index, } alloced_pages = zs_get_total_pages(meta->mem_pool); + update_used_max(zram, alloced_pages); + if (zram->limit_pages && alloced_pages > zram->limit_pages) { zs_free(meta->mem_pool, handle); ret = -ENOMEM; goto out; } - update_used_max(zram, alloced_pages); - cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_WO); if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) { |