sunrpc: make the cache cleaner workqueue deferrable (8eab945c) · Commits · 戴 / test

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@nokia.com> Signed-off-by:

J. Bruce Fields <bfields@citi.umich.edu>

include/linux/sunrpc/cache.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

net/sunrpc/cache.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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;

net/sunrpc/sunrpc_syms.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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