From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f45.google.com (mail-pa0-f45.google.com [209.85.220.45]) by kanga.kvack.org (Postfix) with ESMTP id 989556B0253 for ; Mon, 14 Sep 2015 20:59:58 -0400 (EDT) Received: by padhk3 with SMTP id hk3so158593503pad.3 for ; Mon, 14 Sep 2015 17:59:58 -0700 (PDT) Received: from mail-pa0-x22f.google.com (mail-pa0-x22f.google.com. [2607:f8b0:400e:c03::22f]) by mx.google.com with ESMTPS id f2si27263786pas.105.2015.09.14.17.59.57 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 14 Sep 2015 17:59:57 -0700 (PDT) Received: by pacex6 with SMTP id ex6so159087024pac.0 for ; Mon, 14 Sep 2015 17:59:57 -0700 (PDT) Date: Tue, 15 Sep 2015 10:00:43 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH 1/3] zram: make max_zpage_size configurable Message-ID: <20150915010043.GB1860@swordfish> References: <20150914154901.92c5b7b24e15f04d8204de18@gmail.com> <20150914155036.7c90a8e313cb0ed4d4857934@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150914155036.7c90a8e313cb0ed4d4857934@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Vitaly Wool Cc: minchan@kernel.org, sergey.senozhatsky@gmail.com, ddstreet@ieee.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On (09/14/15 15:50), Vitaly Wool wrote: > It makes sense to have control over what compression ratios are > ok to store pages uncompressed and what not. um... I don't want this to be exported. this is very 'zram-internal'. besides, you remove the exsiting default value - static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; so now people must provide this module param in order to make zram work the way it used to work for years? > Moreover, if we end up using zbud allocator for zram, any attempt to > allocate a whole page will fail, so we may want to avoid this as much > as possible. so how does it help? > So, let's have max_zpage_size configurable as a module parameter. > > Signed-off-by: Vitaly Wool > --- > drivers/block/zram/zram_drv.c | 13 +++++++++++++ > drivers/block/zram/zram_drv.h | 16 ---------------- > 2 files changed, 13 insertions(+), 16 deletions(-) > > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 9fa15bb..6d9f1d1 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -42,6 +42,7 @@ static const char *default_compressor = "lzo"; > > /* Module params (documentation at end) */ > static unsigned int num_devices = 1; > +static size_t max_zpage_size = PAGE_SIZE / 4 * 3; > > static inline void deprecated_attr_warn(const char *name) > { > @@ -1411,6 +1412,16 @@ static int __init zram_init(void) > return ret; > } > > + /* > + * max_zpage_size must be less than or equal to: > + * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would > + * always return failure. > + */ > + if (max_zpage_size > PAGE_SIZE) { > + pr_err("Invalid max_zpage_size %ld\n", max_zpage_size); and how do people find out ZS_MAX_ALLOC_SIZE? this error message does not help. > + return -EINVAL; > + } > + > zram_major = register_blkdev(0, "zram"); > if (zram_major <= 0) { > pr_err("Unable to get major number\n"); > @@ -1444,6 +1455,8 @@ module_exit(zram_exit); > > module_param(num_devices, uint, 0); > MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices"); > +module_param(max_zpage_size, ulong, 0); > +MODULE_PARM_DESC(max_zpage_size, "Threshold for storing compressed pages"); unclear description. > > MODULE_LICENSE("Dual BSD/GPL"); > MODULE_AUTHOR("Nitin Gupta "); > diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h > index 8e92339..3a29c33 100644 > --- a/drivers/block/zram/zram_drv.h > +++ b/drivers/block/zram/zram_drv.h > @@ -20,22 +20,6 @@ > > #include "zcomp.h" > > -/*-- Configurable parameters */ > - > -/* > - * Pages that compress to size greater than this are stored > - * uncompressed in memory. > - */ > -static const size_t max_zpage_size = PAGE_SIZE / 4 * 3; > - > -/* > - * NOTE: max_zpage_size must be less than or equal to: > - * ZS_MAX_ALLOC_SIZE. Otherwise, zs_malloc() would > - * always return failure. > - */ > - > -/*-- End of configurable params */ > - > #define SECTOR_SHIFT 9 > #define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) > #define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) > -- > 1.9.1 > > -- > 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