From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
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 <Artem.Bityutskiy@xxxxxxxxx>
---
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
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