Return-Path: Received: from smtp.nokia.com ([192.100.122.230]:56369 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751847Ab0GAPJp (ORCPT ); Thu, 1 Jul 2010 11:09:45 -0400 From: Artem Bityutskiy To: "J. Bruce Fields" , Neil Brown Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] sunrpc: make the cache cleaner workqueue deferrable Date: Thu, 1 Jul 2010 18:05:56 +0300 Message-Id: <1277996756-8415-1-git-send-email-dedekind1@gmail.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Content-Type: text/plain MIME-Version: 1.0 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. 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