aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMateusz Guzik <mjg@FreeBSD.org>2020-08-26 12:54:18 +0000
committerMateusz Guzik <mjg@FreeBSD.org>2020-08-26 12:54:18 +0000
commit1e9a0b391d88e0f9a9cb5b1d49aba61f80ae97f5 (patch)
treef919bd00bcab30604880cb3e9a5dc87f8623c621
parent075f58f2319688420d8c4a70e333dd5d8e3c6816 (diff)
downloadsrc-1e9a0b391d88e0f9a9cb5b1d49aba61f80ae97f5.tar.gz
src-1e9a0b391d88e0f9a9cb5b1d49aba61f80ae97f5.zip
cache: relock on failure in cache_zap_locked_vnode
This gets rid of bogus scheme of yielding in hopes the blocking thread will make progress.
Notes
Notes: svn path=/head/; revision=364816
-rw-r--r--sys/kern/vfs_cache.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 5ac88c0b2774..2c20065c8ba0 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -1134,8 +1134,15 @@ cache_zap_locked_vnode(struct namecache *ncp, struct vnode *vp)
to_unlock = vlp2;
} else {
if (!mtx_trylock(vlp1)) {
- error = EAGAIN;
- goto out;
+ /*
+ * TODO: Very wasteful but rare.
+ */
+ mtx_unlock(pvlp);
+ mtx_lock(vlp1);
+ mtx_lock(vlp2);
+ mtx_unlock(vlp2);
+ mtx_unlock(vlp1);
+ return (EAGAIN);
}
to_unlock = vlp1;
}
@@ -1377,7 +1384,6 @@ negative_success:
error = cache_zap_locked_vnode(ncp, dvp);
if (__predict_false(error != 0)) {
zap_and_exit_bucket_fail2++;
- cache_maybe_yield();
goto retry;
}
cache_free(ncp);
@@ -1465,7 +1471,6 @@ retry:
error = cache_zap_locked_bucket(ncp, cnp, hash, blp);
if (__predict_false(error != 0)) {
zap_and_exit_bucket_fail++;
- cache_maybe_yield();
goto retry;
}
counter_u64_add(numposzaps, 1);
@@ -1584,7 +1589,6 @@ negative_success:
error = cache_zap_locked_vnode(ncp, dvp);
if (__predict_false(error != 0)) {
zap_and_exit_bucket_fail2++;
- cache_maybe_yield();
goto retry;
}
cache_free(ncp);