From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752112AbaHTCI4 (ORCPT ); Tue, 19 Aug 2014 22:08:56 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:40297 "EHLO lgemrelse7q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751733AbaHTCIz (ORCPT ); Tue, 19 Aug 2014 22:08:55 -0400 X-Original-SENDERIP: 10.177.222.156 X-Original-MAILFROM: minchan@kernel.org Date: Wed, 20 Aug 2014 11:09:24 +0900 From: Minchan Kim To: Sergey Senozhatsky Cc: Chao Yu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, ngupta@vflare.org, "'Jerome Marchand'" , "'Andrew Morton'" Subject: Re: [PATCH] zram: add num_discards for discarded pages stat Message-ID: <20140820020924.GD32620@bbox> References: <001201cfb838$fb0ac4a0$f1204de0$@samsung.com> <20140815061138.GA940@swordfish> <002d01cfbb70$ea7410c0$bf5c3240$@samsung.com> <20140819112500.GA2484@swordfish> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20140819112500.GA2484@swordfish> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sergey, On Tue, Aug 19, 2014 at 08:25:00PM +0900, Sergey Senozhatsky wrote: > Hello, > > On (08/19/14 13:45), Chao Yu wrote: > > > On (08/15/14 11:27), Chao Yu wrote: > > > > Now we have supported handling discard request which is sended by filesystem, > > > > but no interface could be used to show information of discard. > > > > This patch adds num_discards to stat discarded pages, then export it to sysfs > > > > for displaying. > > > > > > > > > > a side question: we account discarded pages via slot free notify in > > > notify_free and via req_discard in num_discards. how about accounting > > > both of them in num_discards? because, after all, they account a number > > > of discarded pages (zram_free_page()). or there any particular reason we > > > want to distinguish. > > > > Yeah, I agree with you as I have no such reason unless there are our users' > > explicitly requirement for showing notify_free/num_discards separately later. > > > > How do you think of sending another patch to merge these two counts? > > > > Minchan, what do you think? let's account discarded pages in one place. First of all, I'd like to know why we need num_discards. It should be in description and depends on it whether we should merge both counts or separate. Thanks. > > > One more thing is that I am missing to update document of zram, sorry about > > that, let me update it in v2. > > thanks. > > -ss > > > Thanks, > > Yu > > > > > > > > -ss > > > > > > > Signed-off-by: Chao Yu > > > > --- > > > > Documentation/ABI/testing/sysfs-block-zram | 10 ++++++++++ > > > > drivers/block/zram/zram_drv.c | 3 +++ > > > > drivers/block/zram/zram_drv.h | 1 + > > > > 3 files changed, 14 insertions(+) > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-block-zram > > > b/Documentation/ABI/testing/sysfs-block-zram > > > > index 70ec992..fa8936e 100644 > > > > --- a/Documentation/ABI/testing/sysfs-block-zram > > > > +++ b/Documentation/ABI/testing/sysfs-block-zram > > > > @@ -57,6 +57,16 @@ Description: > > > > The failed_writes file is read-only and specifies the number of > > > > failed writes happened on this device. > > > > > > > > + > > > > +What: /sys/block/zram/num_discards > > > > +Date: August 2014 > > > > +Contact: Chao Yu > > > > +Description: > > > > + The num_discards file is read-only and specifies the number of > > > > + physical blocks which are discarded by this device. These blocks > > > > + are included in discard request which is sended by filesystem as > > > > + the blocks are no longer used. > > > > + > > > > What: /sys/block/zram/max_comp_streams > > > > Date: February 2014 > > > > Contact: Sergey Senozhatsky > > > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > > > > index d00831c..904e7a5 100644 > > > > --- a/drivers/block/zram/zram_drv.c > > > > +++ b/drivers/block/zram/zram_drv.c > > > > @@ -606,6 +606,7 @@ static void zram_bio_discard(struct zram *zram, u32 index, > > > > bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value); > > > > zram_free_page(zram, index); > > > > bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value); > > > > + atomic64_inc(&zram->stats.num_discards); > > > > index++; > > > > n -= PAGE_SIZE; > > > > } > > > > @@ -866,6 +867,7 @@ ZRAM_ATTR_RO(num_reads); > > > > ZRAM_ATTR_RO(num_writes); > > > > ZRAM_ATTR_RO(failed_reads); > > > > ZRAM_ATTR_RO(failed_writes); > > > > +ZRAM_ATTR_RO(num_discards); > > > > ZRAM_ATTR_RO(invalid_io); > > > > ZRAM_ATTR_RO(notify_free); > > > > ZRAM_ATTR_RO(zero_pages); > > > > @@ -879,6 +881,7 @@ static struct attribute *zram_disk_attrs[] = { > > > > &dev_attr_num_writes.attr, > > > > &dev_attr_failed_reads.attr, > > > > &dev_attr_failed_writes.attr, > > > > + &dev_attr_num_discards.attr, > > > > &dev_attr_invalid_io.attr, > > > > &dev_attr_notify_free.attr, > > > > &dev_attr_zero_pages.attr, > > > > diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h > > > > index e0f725c..2994aaf 100644 > > > > --- a/drivers/block/zram/zram_drv.h > > > > +++ b/drivers/block/zram/zram_drv.h > > > > @@ -86,6 +86,7 @@ struct zram_stats { > > > > atomic64_t num_writes; /* --do-- */ > > > > atomic64_t failed_reads; /* can happen when memory is too low */ > > > > atomic64_t failed_writes; /* can happen when memory is too low */ > > > > + atomic64_t num_discards; /* no. of discarded pages */ > > > > atomic64_t invalid_io; /* non-page-aligned I/O requests */ > > > > atomic64_t notify_free; /* no. of swap slot free notifications */ > > > > atomic64_t zero_pages; /* no. of zero filled pages */ > > > > -- > > > > 2.0.1.474.g72c7794 > > > > > > > > > > > > > > -- > > > To unsubscribe, send a message with 'unsubscribe linux-mm' in > > > the body to majordomo@kvack.org. For more info on Linux MM, > > > see: http://www.linux-mm.org/ . > > > Don't email: email@kvack.org > > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Kind regards, Minchan Kim