From 8e1f936b73150f5095448a0fee6d4f30a1f9001d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 17 Jul 2007 04:03:17 -0700 Subject: mm: clean up and kernelify shrinker registration I can never remember what the function to register to receive VM pressure is called. I have to trace down from __alloc_pages() to find it. It's called "set_shrinker()", and it needs Your Help. 1) Don't hide struct shrinker. It contains no magic. 2) Don't allocate "struct shrinker". It's not helpful. 3) Call them "register_shrinker" and "unregister_shrinker". 4) Call the function "shrink" not "shrinker". 5) Reduce the 17 lines of waffly comments to 13, but document it properly. Signed-off-by: Rusty Russell Cc: David Chinner Cc: Trond Myklebust Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmscan.c | 42 +++++++++++------------------------------- 1 file changed, 11 insertions(+), 31 deletions(-) (limited to 'mm/vmscan.c') diff --git a/mm/vmscan.c b/mm/vmscan.c index 1d9971d8924b..2225b7c9df85 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -70,17 +70,6 @@ struct scan_control { int order; }; -/* - * The list of shrinker callbacks used by to apply pressure to - * ageable caches. - */ -struct shrinker { - shrinker_t shrinker; - struct list_head list; - int seeks; /* seeks to recreate an obj */ - long nr; /* objs pending delete */ -}; - #define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru)) #ifdef ARCH_HAS_PREFETCH @@ -123,34 +112,25 @@ static DECLARE_RWSEM(shrinker_rwsem); /* * Add a shrinker callback to be called from the vm */ -struct shrinker *set_shrinker(int seeks, shrinker_t theshrinker) +void register_shrinker(struct shrinker *shrinker) { - struct shrinker *shrinker; - - shrinker = kmalloc(sizeof(*shrinker), GFP_KERNEL); - if (shrinker) { - shrinker->shrinker = theshrinker; - shrinker->seeks = seeks; - shrinker->nr = 0; - down_write(&shrinker_rwsem); - list_add_tail(&shrinker->list, &shrinker_list); - up_write(&shrinker_rwsem); - } - return shrinker; + shrinker->nr = 0; + down_write(&shrinker_rwsem); + list_add_tail(&shrinker->list, &shrinker_list); + up_write(&shrinker_rwsem); } -EXPORT_SYMBOL(set_shrinker); +EXPORT_SYMBOL(register_shrinker); /* * Remove one */ -void remove_shrinker(struct shrinker *shrinker) +void unregister_shrinker(struct shrinker *shrinker) { down_write(&shrinker_rwsem); list_del(&shrinker->list); up_write(&shrinker_rwsem); - kfree(shrinker); } -EXPORT_SYMBOL(remove_shrinker); +EXPORT_SYMBOL(unregister_shrinker); #define SHRINK_BATCH 128 /* @@ -187,7 +167,7 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; unsigned long total_scan; - unsigned long max_pass = (*shrinker->shrinker)(0, gfp_mask); + unsigned long max_pass = (*shrinker->shrink)(0, gfp_mask); delta = (4 * scanned) / shrinker->seeks; delta *= max_pass; @@ -215,8 +195,8 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask, int shrink_ret; int nr_before; - nr_before = (*shrinker->shrinker)(0, gfp_mask); - shrink_ret = (*shrinker->shrinker)(this_scan, gfp_mask); + nr_before = (*shrinker->shrink)(0, gfp_mask); + shrink_ret = (*shrinker->shrink)(this_scan, gfp_mask); if (shrink_ret == -1) break; if (shrink_ret < nr_before) -- cgit v1.2.3-59-g8ed1b