From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 17 Aug 2007 12:20:30 -0400 From: Josef Sipek Subject: Re: [PATCH 16/23] mm: scalable bdi statistics counters. Message-ID: <20070817162030.GA27836@filer.fsl.cs.sunysb.edu> References: <20070816074525.065850000@chello.nl> <20070816074628.520798000@chello.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070816074628.520798000@chello.nl> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, torvalds@linux-foundation.org List-ID: On Thu, Aug 16, 2007 at 09:45:41AM +0200, Peter Zijlstra wrote: ... > Index: linux-2.6/include/linux/backing-dev.h > =================================================================== > --- linux-2.6.orig/include/linux/backing-dev.h > +++ linux-2.6/include/linux/backing-dev.h ... > @@ -24,6 +26,12 @@ enum bdi_state { > > typedef int (congested_fn)(void *, int); > > +enum bdi_stat_item { > + NR_BDI_STAT_ITEMS > +}; enum numbering starts at 0, so NR_BDI_STAT_ITEMS == 0 > + > +#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids))) > + > struct backing_dev_info { > unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ > unsigned long state; /* Always use atomic bitops on this */ > @@ -32,15 +40,86 @@ struct backing_dev_info { > void *congested_data; /* Pointer to aux data for congested func */ > void (*unplug_io_fn)(struct backing_dev_info *, struct page *); > void *unplug_io_data; > + > + struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS]; So, this is a 0-element array. > }; > > -static inline int bdi_init(struct backing_dev_info *bdi) > +int bdi_init(struct backing_dev_info *bdi); > +void bdi_destroy(struct backing_dev_info *bdi); > + > +static inline void __add_bdi_stat(struct backing_dev_info *bdi, > + enum bdi_stat_item item, s64 amount) > { > - return 0; > + __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH); Boom! > } Josef 'Jeff' Sipek. -- You measure democracy by the freedom it gives its dissidents, not the freedom it gives its assimilated conformists. - Abbie Hoffman -- 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