[PATCH] fix return value for mb_cache_shrink_fn when nr_to_scan > 0
in [Kernel]
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From: Wang Sheng-Hui on 21 Jul 2010 07:00 Sorry. regerated the patch, please check it. I wrapped most code in single pair of spinlock ops for 2 reasons: 1) get spinlock 2 times seems time consuming 2) use single pair of spinlock ops can keep "count" consistent for the shrink operation. 2 pairs may get some new ces created by other processes. Signed-off-by: Wang Sheng-Hui <crosslonelyover(a)gmail.com> --- fs/mbcache.c | 24 ++++++++++++------------ 1 files changed, 12 insertions(+), 12 deletions(-) diff --git a/fs/mbcache.c b/fs/mbcache.c index ec88ff3..ee57aa3 100644 --- a/fs/mbcache.c +++ b/fs/mbcache.c @@ -201,21 +201,15 @@ mb_cache_shrink_fn(int nr_to_scan, gfp_t gfp_mask) { LIST_HEAD(free_list); struct list_head *l, *ltmp; + struct mb_cache *cache; int count = 0; - spin_lock(&mb_cache_spinlock); - list_for_each(l, &mb_cache_list) { - struct mb_cache *cache = - list_entry(l, struct mb_cache, c_cache_list); - mb_debug("cache %s (%d)", cache->c_name, - atomic_read(&cache->c_entry_count)); - count += atomic_read(&cache->c_entry_count); - } mb_debug("trying to free %d entries", nr_to_scan); - if (nr_to_scan == 0) { - spin_unlock(&mb_cache_spinlock); + + spin_lock(&mb_cache_spinlock); + if (nr_to_scan == 0) goto out; - } + while (nr_to_scan-- && !list_empty(&mb_cache_lru_list)) { struct mb_cache_entry *ce = list_entry(mb_cache_lru_list.next, @@ -223,12 +217,18 @@ mb_cache_shrink_fn(int nr_to_scan, gfp_t gfp_mask) list_move_tail(&ce->e_lru_list, &free_list); __mb_cache_entry_unhash(ce); } - spin_unlock(&mb_cache_spinlock); list_for_each_safe(l, ltmp, &free_list) { __mb_cache_entry_forget(list_entry(l, struct mb_cache_entry, e_lru_list), gfp_mask); } out: + list_for_each_entry(cache, &mb_cache_list, c_cache_list) { + mb_debug("cache %s (%d)", cache->c_name, + atomic_read(&cache->c_entry_count)); + count += atomic_read(&cache->c_entry_count); + } + spin_unlock(&mb_cache_spinlock); + return (count / 100) * sysctl_vfs_cache_pressure; } -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |