From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by py-out-1112.google.com with SMTP id f47so2706630pye.20 for ; Mon, 24 Mar 2008 09:05:13 -0700 (PDT) Message-ID: <87a5b0800803240905g705a8ea3p11c415ad37fc3cbb@mail.gmail.com> Date: Mon, 24 Mar 2008 16:05:12 +0000 From: "Will Newton" Subject: Re: [PATCH 2/6] compcache: block device - internal defs In-Reply-To: <200803242033.30782.nitingupta910@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200803242033.30782.nitingupta910@gmail.com> Sender: owner-linux-mm@kvack.org Return-Path: To: nitingupta910@gmail.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Mon, Mar 24, 2008 at 3:03 PM, Nitin Gupta wrote: Hi Nitin, > This contains header to be used internally by block device code. > It contains flags to enable/disable debugging, stats collection and also > defines default disk size (25% of total RAM). > > Signed-off-by: Nitin Gupta > --- > drivers/block/compcache.h | 147 +++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 147 insertions(+), 0 deletions(-) > > diff --git a/drivers/block/compcache.h b/drivers/block/compcache.h > new file mode 100644 > index 0000000..b84b5d3 > --- /dev/null > +++ b/drivers/block/compcache.h > @@ -0,0 +1,147 @@ > +/* > + * Compressed RAM based swap device > + * > + * (C) Nitin Gupta > + * > + * This RAM based block device acts as swap disk. > + * Pages swapped to this device are compressed and > + * stored in memory. > + * > + * Project home: http://code.google.com/p/compcache > + */ > + > +#ifndef _COMPCACHE_H_ > +#define _COMPCACHE_H_ > + > +#define K(x) ((x) >> 10) > +#define KB(x) ((x) << 10) > + > +#define SECTOR_SHIFT 9 > +#define SECTOR_SIZE (1 << SECTOR_SHIFT) > +#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT) > +#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT) > + > +/*-- Configurable parameters */ > +/* Default compcache size: 25% of total RAM */ > +#define DEFAULT_COMPCACHE_PERCENT 25 > +#define INIT_SIZE KB(16) > +#define GROW_SIZE INIT_SIZE Maybe these could be renamed to INIT_SIZE_BYTES/GROW_SIZE_BYTES to make the units clearer? > +/*-- */ > + > +/* Message prefix */ > +#define C "compcache: " > + > +/* Debugging and Stats */ > +#define NOP do { } while(0) > + > +#if (1 || defined(CONFIG_DEBUG_COMPCACHE)) > +#define DEBUG 1 > +#define STATS 1 > +#else > +#define DEBUG 0 > +#define STATS 0 > +#endif If DEBUG is defined unconditionally what is the point of CONFIG_DEBUG_COMPCACHE? > + > +/* Create /proc/compcache? */ > +/* If STATS is disabled, this will give minimal compcache info */ > +#define CONFIG_COMPCACHE_PROC > + > +#if DEBUG > +#define CC_DEBUG(fmt,arg...) \ > + printk(KERN_DEBUG C fmt,##arg) > +#else > +#define CC_DEBUG(fmt,arg...) NOP > +#endif Have you thought about using pr_debug() for this? It looks like it would simplify this file at the cost of a little flexibility. > + > +/* > + * Verbose debugging: > + * Enable basic debugging + verbose messages spread all over code > + */ > +#define DEBUG2 0 > + > +#if DEBUG2 > +#define DEBUG 1 > +#define STATS 1 > +#define CONFIG_COMPCACHE_PROC 1 > +#define CC_DEBUG2((fmt,arg...) \ > + printk(KERN_DEBUG C fmt,##arg) > +#else /* DEBUG2 */ > +#define CC_DEBUG2(fmt,arg...) NOP > +#endif > + > +/* Its useless to collect stats if there is no way to export it */ > +#if (STATS && !defined(CONFIG_COMPCACHE_PROC)) > +#error "compcache stats is enabled but not /proc/compcache." > +#endif So it appears that if we want DEBUG we also get STATS, which requires /proc support enabled, so it is impossible to have just DEBUG and no STATS or /proc support? -- 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