On (05/03/16 11:30), Sergey Senozhatsky wrote: > > We are concerning about returing back to no per-cpu options but actually, > > I don't want. If duplicate compression is really problem(But It's really > > unlikely), we should try to solve the problem itself with different way > > rather than roll-back to old, first of all. > > > > I hope we can. So let's not add big worry about adding new dup stat. :) > > ok, no prob. do you want it a separate sysfs node or a column in mm_stat? > I'd prefer mm_stat column, or somewhere in those cumulative files; not a > dedicated node: we decided to get rid of them some time ago. >
will io_stat node work for you? I'll submit a formal patch later today. when you have time, can you take a look at http://marc.info/?l=linux-kernel&m=146217628030970 ? I think we can fold this one into 0002. it will make 0002 slightly bigger, but there nothing complicated in there, just cleanup. ==== From: Sergey Senozhatsky <sergey.senozhat...@gmail.com> Subject: [PATCH] zram: export the number of re-compressions Make the number of re-compressions visible via the io_stat node, so we will be able to track down any issues caused by per-cpu compression streams. Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com> Suggested-by: Minchan Kim <minc...@kernel.org> --- Documentation/blockdev/zram.txt | 3 +++ drivers/block/zram/zram_drv.c | 7 +++++-- drivers/block/zram/zram_drv.h | 1 + 3 files changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 5bda503..386d260 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -183,6 +183,8 @@ mem_limit RW the maximum amount of memory ZRAM can use to store pages_compacted RO the number of pages freed during compaction (available only via zram<id>/mm_stat node) compact WO trigger memory compaction +num_recompress RO the number of times fast compression paths failed + and zram performed re-compression via a slow path WARNING ======= @@ -215,6 +217,7 @@ whitespace: failed_writes invalid_io notify_free + num_recompress File /sys/block/zram<id>/mm_stat diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 817e511..11b19c9 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -395,7 +395,8 @@ static ssize_t io_stat_show(struct device *dev, (u64)atomic64_read(&zram->stats.failed_reads), (u64)atomic64_read(&zram->stats.failed_writes), (u64)atomic64_read(&zram->stats.invalid_io), - (u64)atomic64_read(&zram->stats.notify_free)); + (u64)atomic64_read(&zram->stats.notify_free), + (u64)atomic64_read(&zram->stats.num_recompress)); up_read(&zram->init_lock); return ret; @@ -721,8 +722,10 @@ compress_again: handle = zs_malloc(meta->mem_pool, clen, GFP_NOIO | __GFP_HIGHMEM); - if (handle) + if (handle) { + atomic64_inc(&zram->stats.num_recompress); goto compress_again; + } pr_err("Error allocating memory for compressed page: %u, size=%zu\n", index, clen); diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h index 06b1636..78d7e8f 100644 --- a/drivers/block/zram/zram_drv.h +++ b/drivers/block/zram/zram_drv.h @@ -85,6 +85,7 @@ struct zram_stats { atomic64_t zero_pages; /* no. of zero filled pages */ atomic64_t pages_stored; /* no. of pages currently stored */ atomic_long_t max_used_pages; /* no. of maximum pages stored */ + atomic64_t num_recompress; /* no. of failed compression fast paths */ }; struct zram_meta { -- 2.8.2
