From 17cebf658e088935d4bdebfc7ad9800e9fc4a0b2 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 12 Aug 2010 16:55:22 +1000 Subject: sunrpc: extract some common sunrpc_cache code from nfsd Rather can duplicating this idiom twice, put it in an inline function. This reduces the usage of 'expiry_time' out side the sunrpc/cache.c code and thus the impact of a change that is about to be made to that field. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/sunrpc/cache.h') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index 7bf3e84b92f4..0e1febf4e5bc 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -228,4 +228,10 @@ static inline time_t get_expiry(char **bpp) return rv; } +static inline void sunrpc_invalidate(struct cache_head *h, + struct cache_detail *detail) +{ + h->expiry_time = get_seconds() - 1; + detail->nextcheck = get_seconds(); +} #endif /* _LINUX_SUNRPC_CACHE_H_ */ -- cgit v1.2.2 From c5b29f885afe890f953f7f23424045cdad31d3e4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 12 Aug 2010 16:55:22 +1000 Subject: sunrpc: use seconds since boot in expiry cache This protects us from confusion when the wallclock time changes. We convert to and from wallclock when setting or reading expiry times. Also use seconds since boot for last_clost time. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) (limited to 'include/linux/sunrpc/cache.h') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index 0e1febf4e5bc..ece432b7f87f 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -218,20 +218,42 @@ static inline int get_int(char **bpp, int *anint) return 0; } +/* + * timestamps kept in the cache are expressed in seconds + * since boot. This is the best for measuring differences in + * real time. + */ +static inline time_t seconds_since_boot(void) +{ + struct timespec boot; + getboottime(&boot); + return get_seconds() - boot.tv_sec; +} + +static inline time_t convert_to_wallclock(time_t sinceboot) +{ + struct timespec boot; + getboottime(&boot); + return boot.tv_sec + sinceboot; +} + static inline time_t get_expiry(char **bpp) { int rv; + struct timespec boot; + if (get_int(bpp, &rv)) return 0; if (rv < 0) return 0; - return rv; + getboottime(&boot); + return rv - boot.tv_sec; } static inline void sunrpc_invalidate(struct cache_head *h, struct cache_detail *detail) { - h->expiry_time = get_seconds() - 1; - detail->nextcheck = get_seconds(); + h->expiry_time = seconds_since_boot() - 1; + detail->nextcheck = seconds_since_boot(); } #endif /* _LINUX_SUNRPC_CACHE_H_ */ -- cgit v1.2.2 From f16b6e8d838b2e2bb4561201311c66ac02ad67df Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 12 Aug 2010 17:04:06 +1000 Subject: sunrpc/cache: allow threads to block while waiting for cache update. The current practice of waiting for cache updates by queueing the whole request to be retried has (at least) two problems. 1/ With NFSv4, requests can be quite complex and re-trying a whole request when a later part fails should only be a last-resort, not a normal practice. 2/ Large requests, and in particular any 'write' request, will not be queued by the current code and doing so would be undesirable. In many cases only a very sort wait is needed before the cache gets valid data. So, providing the underlying transport permits it by setting ->thread_wait, arrange to wait briefly for an upcall to be completed (as reflected in the clearing of CACHE_PENDING). If the short wait was not long enough and CACHE_PENDING is still set, fall back on the old approach. The 'thread_wait' value is set to 5 seconds when there are spare threads, and 1 second when there are no spare threads. These values are probably much higher than needed, but will ensure some forward progress. Note that as we only request an update for a non-valid item, and as non-valid items are updated in place it is extremely unlikely that cache_check will return -ETIMEDOUT. Normally cache_defer_req will sleep for a short while and then find that the item is_valid. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/sunrpc/cache.h') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index ece432b7f87f..52a7d7224e90 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -125,6 +125,9 @@ struct cache_detail { */ struct cache_req { struct cache_deferred_req *(*defer)(struct cache_req *req); + int thread_wait; /* How long (jiffies) we can block the + * current thread to wait for updates. + */ }; /* this must be embedded in a deferred_request that is being * delayed awaiting cache-fill -- cgit v1.2.2 From 1117449276bb909b029ed0b9ba13f53e4784db9d Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Thu, 12 Aug 2010 17:04:08 +1000 Subject: sunrpc/cache: change deferred-request hash table to use hlist. Being a hash table, hlist is the best option. There is currently some ugliness were we treat "->next == NULL" as a special case to avoid having to initialise the whole array. This change nicely gets rid of that case. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/sunrpc/cache.h') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index 52a7d7224e90..03496357f455 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -133,7 +133,7 @@ struct cache_req { * delayed awaiting cache-fill */ struct cache_deferred_req { - struct list_head hash; /* on hash chain */ + struct hlist_node hash; /* on hash chain */ struct list_head recent; /* on fifo */ struct cache_head *item; /* cache item we wait on */ void *owner; /* we might need to discard all defered requests -- cgit v1.2.2 From 593ce16b943ea37d4ec62c377b32d7f3f4085e84 Mon Sep 17 00:00:00 2001 From: Pavel Emelyanov Date: Mon, 27 Sep 2010 14:00:15 +0400 Subject: sunrpc: Add routines that allow registering per-net caches Existing calls do the same, but for the init_net. Signed-off-by: Pavel Emelyanov Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/cache.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/sunrpc/cache.h') diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h index 03496357f455..6950c981882d 100644 --- a/include/linux/sunrpc/cache.h +++ b/include/linux/sunrpc/cache.h @@ -197,7 +197,9 @@ 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 int cache_register_net(struct cache_detail *cd, struct net *net); extern void cache_unregister(struct cache_detail *cd); +extern void cache_unregister_net(struct cache_detail *cd, struct net *net); extern int sunrpc_cache_register_pipefs(struct dentry *parent, const char *, mode_t, struct cache_detail *); -- cgit v1.2.2