From: "J. Bruce Fields" Subject: Re: [PATCH] sunrpc: make the cache cleaner workqueue deferrable Date: Tue, 6 Jul 2010 12:28:16 -0400 Message-ID: <20100706162815.GE7387@fieldses.org> References: <1277996756-8415-1-git-send-email-dedekind1@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Neil Brown , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org To: Artem Bityutskiy Return-path: In-Reply-To: <1277996756-8415-1-git-send-email-dedekind1@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Thu, Jul 01, 2010 at 06:05:56PM +0300, Artem Bityutskiy wrote: > From: Artem Bityutskiy > > This patch makes the cache_cleaner workqueue deferrable, to prevent > unnecessary system wake-ups, which is very important for embedded > battery-powered devices. > > do_cache_clean() is called every 30 seconds at the moment, and often > makes the system wake up from its power-save sleep state. With this > change, when the workqueue uses a deferrable timer, the > do_cache_clean() invocation will be delayed and combined with the > closest "real" wake-up. This improves the power consumption situation. > > Note, I tried to create a DECLARE_DELAYED_WORK_DEFERRABLE() helper > macro, similar to DECLARE_DELAYED_WORK(), but failed because of the > way the timer wheel core stores the deferrable flag (it is the > LSBit in the time->base pointer). My attempt to define a static > variable with this bit set ended up with the "initializer element is > not constant" error. > > Thus, I have to use run-time initialization, so I created a new > cache_initialize() function which is called once when sunrpc is > being initialized. Thanks, applying for 2.6.36. --b. > > Signed-off-by: Artem Bityutskiy > --- > include/linux/sunrpc/cache.h | 1 + > net/sunrpc/cache.c | 7 ++++++- > net/sunrpc/sunrpc_syms.c | 1 + > 3 files changed, 8 insertions(+), 1 deletions(-) > > diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h > index 6f52b4d..7bf3e84 100644 > --- a/include/linux/sunrpc/cache.h > +++ b/include/linux/sunrpc/cache.h > @@ -192,6 +192,7 @@ extern int cache_check(struct cache_detail *detail, > extern void cache_flush(void); > extern void cache_purge(struct cache_detail *detail); > #define NEVER (0x7FFFFFFF) > +extern void __init cache_initialize(void); > extern int cache_register(struct cache_detail *cd); > extern void cache_unregister(struct cache_detail *cd); > > diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c > index 58de76c..939d048 100644 > --- a/net/sunrpc/cache.c > +++ b/net/sunrpc/cache.c > @@ -320,7 +320,7 @@ static struct cache_detail *current_detail; > static int current_index; > > static void do_cache_clean(struct work_struct *work); > -static DECLARE_DELAYED_WORK(cache_cleaner, do_cache_clean); > +static struct delayed_work cache_cleaner; > > static void sunrpc_init_cache_detail(struct cache_detail *cd) > { > @@ -1504,6 +1504,11 @@ static int create_cache_proc_entries(struct cache_detail *cd) > } > #endif > > +void __init cache_initialize(void) > +{ > + INIT_DELAYED_WORK_DEFERRABLE(&cache_cleaner, do_cache_clean); > +} > + > int cache_register(struct cache_detail *cd) > { > int ret; > diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c > index f438347..c52b184 100644 > --- a/net/sunrpc/sunrpc_syms.c > +++ b/net/sunrpc/sunrpc_syms.c > @@ -43,6 +43,7 @@ init_sunrpc(void) > #ifdef CONFIG_PROC_FS > rpc_proc_init(); > #endif > + cache_initialize(); > cache_register(&ip_map_cache); > cache_register(&unix_gid_cache); > svc_init_xprt_sock(); /* svc sock transport */ > -- > 1.7.0.1 >