From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751987AbaHMLeM (ORCPT ); Wed, 13 Aug 2014 07:34:12 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:39865 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750835AbaHMLeL (ORCPT ); Wed, 13 Aug 2014 07:34:11 -0400 Date: Wed, 13 Aug 2014 20:32:57 +0900 From: Sergey Senozhatsky To: Jerome Marchand Cc: Chao Yu , minchan@kernel.org, ngupta@vflare.org, linux-kernel@vger.kernel.org, "'Sergey Senozhatsky'" , "'Andrew Morton'" Subject: Re: [PATCH v2] zram: fix incorrectly stat with failed_reads Message-ID: <20140813113257.GA948@swordfish> References: <009001cfb69a$a8470840$f8d518c0$@samsung.com> <53EB2271.1080002@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53EB2271.1080002@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (08/13/14 10:31), Jerome Marchand wrote: > Date: Wed, 13 Aug 2014 10:31:45 +0200 > From: Jerome Marchand > To: Chao Yu , minchan@kernel.org > CC: ngupta@vflare.org, linux-kernel@vger.kernel.org, 'Sergey Senozhatsky' > , 'Andrew Morton' > > Subject: Re: [PATCH v2] zram: fix incorrectly stat with failed_reads > User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 > Thunderbird/24.6.0 > > On 08/13/2014 04:01 AM, Chao Yu wrote: > > Since we allocate a temporary buffer in zram_bvec_read to handle partial page > > operations in this commit 924bd88d703e53d30f393fac6117f8f1bc79aab6 (Staging: > > zram: allow partial page operations), our ->failed_reads value may be incorrect > > as we do not increase its value when failed to allocate the temporary buffer. > > > > Let's fix this issue and correct the annotation of failed_reads. > > > > v2: clean codes of failed_{reads,writes} stat pointed out by Minchan Kim, and > > this cleanup also fix incorrectly stat when fail in zram_decompress_page. > > > > Signed-off-by: Chao Yu > > Acked-by: Jerome Marchand Acked-by: Sergey Senozhatsky -ss > > --- > > drivers/block/zram/zram_drv.c | 10 +++++++--- > > drivers/block/zram/zram_drv.h | 2 +- > > 2 files changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > > index dfa4024..d00831c 100644 > > --- a/drivers/block/zram/zram_drv.c > > +++ b/drivers/block/zram/zram_drv.c > > @@ -378,7 +378,6 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index) > > /* Should NEVER happen. Return bio error if it does. */ > > if (unlikely(ret)) { > > pr_err("Decompression failed! err=%d, page=%u\n", ret, index); > > - atomic64_inc(&zram->stats.failed_reads); > > return ret; > > } > > > > @@ -547,8 +546,6 @@ out: > > zcomp_strm_release(zram->comp, zstrm); > > if (is_partial_io(bvec)) > > kfree(uncmem); > > - if (ret) > > - atomic64_inc(&zram->stats.failed_writes); > > return ret; > > } > > > > @@ -566,6 +563,13 @@ static int zram_bvec_rw(struct zram *zram, struct bio_vec *bvec, u32 index, > > ret = zram_bvec_write(zram, bvec, index, offset); > > } > > > > + if (unlikely(ret)) { > > + if (rw == READ) > > + atomic64_inc(&zram->stats.failed_reads); > > + else > > + atomic64_inc(&zram->stats.failed_writes); > > + } > > + > > return ret; > > } > > > > diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h > > index 5b0afde..e0f725c 100644 > > --- a/drivers/block/zram/zram_drv.h > > +++ b/drivers/block/zram/zram_drv.h > > @@ -84,7 +84,7 @@ struct zram_stats { > > atomic64_t compr_data_size; /* compressed size of pages stored */ > > atomic64_t num_reads; /* failed + successful */ > > atomic64_t num_writes; /* --do-- */ > > - atomic64_t failed_reads; /* should NEVER! happen */ > > + atomic64_t failed_reads; /* can happen when memory is too low */ > > atomic64_t failed_writes; /* can happen when memory is too low */ > > atomic64_t invalid_io; /* non-page-aligned I/O requests */ > > atomic64_t notify_free; /* no. of swap slot free notifications */ > > > >