From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932340AbcECE1a (ORCPT ); Tue, 3 May 2016 00:27:30 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:35458 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750846AbcECE12 (ORCPT ); Tue, 3 May 2016 00:27:28 -0400 Date: Tue, 3 May 2016 13:29:02 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Sergey Senozhatsky , Sergey Senozhatsky , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] zram: user per-cpu compression streams Message-ID: <20160503042902.GA25545@swordfish> References: <1461860230-849-1-git-send-email-sergey.senozhatsky@gmail.com> <1461860230-849-3-git-send-email-sergey.senozhatsky@gmail.com> <20160502062311.GB6077@bbox> <20160502072508.GA1811@swordfish> <20160502082822.GC6077@bbox> <20160502092157.GA21764@swordfish> <20160503014018.GB2272@bbox> <20160503015333.GA9987@swordfish> <20160503022046.GB3642@bbox> <20160503023001.GB9987@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160503023001.GB9987@swordfish> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 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 Suggested-by: Minchan Kim --- 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/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/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