Author: mjg
Date: Thu May 4 03:11:59 2017
New Revision: 317784
URL: https://svnweb.freebsd.org/changeset/base/317784
Log:
cache: stop holding the ncneg_hot lock across purging
Only non-hot entries are purged so the lock is not needed in the first place.
This saves one lock/unlock pair.
MFC after: 1 week
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Thu May 4 01:46:04 2017 (r317783)
+++ head/sys/kern/vfs_cache.c Thu May 4 03:11:59 2017 (r317784)
@@ -735,13 +735,12 @@ cache_negative_remove(struct namecache *
list_locked = true;
mtx_lock(&neglist->nl_lock);
}
- } else {
- mtx_assert(&neglist->nl_lock, MA_OWNED);
- mtx_assert(&ncneg_hot.nl_lock, MA_OWNED);
}
if (ncp->nc_flag & NCF_HOTNEGATIVE) {
+ mtx_assert(&ncneg_hot.nl_lock, MA_OWNED);
TAILQ_REMOVE(&ncneg_hot.nl_list, ncp, nc_dst);
} else {
+ mtx_assert(&neglist->nl_lock, MA_OWNED);
TAILQ_REMOVE(&neglist->nl_list, ncp, nc_dst);
}
if (list_locked)
@@ -816,7 +815,6 @@ cache_negative_zap_one(void)
mtx_unlock(&ncneg_hot.nl_lock);
mtx_lock(dvlp);
rw_wlock(blp);
- mtx_lock(&ncneg_hot.nl_lock);
mtx_lock(&neglist->nl_lock);
ncp2 = TAILQ_FIRST(&neglist->nl_list);
if (ncp != ncp2 || dvlp != VP2VNODELOCK(ncp2->nc_dvp) ||
@@ -830,7 +828,6 @@ cache_negative_zap_one(void)
cache_zap_locked(ncp, true);
out_unlock_all:
mtx_unlock(&neglist->nl_lock);
- mtx_unlock(&ncneg_hot.nl_lock);
rw_wunlock(blp);
mtx_unlock(dvlp);
out:
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