The branch main has been updated by mjg:
URL:
https://cgit.FreeBSD.org/src/commit/?id=02ec31bdf60fa3a8530544cb3c8c4ec1df6cde0d
commit 02ec31bdf60fa3a8530544cb3c8c4ec1df6cde0d
Author: Mateusz Guzik <m...@freebsd.org>
AuthorDate: 2021-01-23 17:21:42 +0000
Commit: Mateusz Guzik <m...@freebsd.org>
CommitDate: 2021-01-23 18:10:16 +0000
cache: add back target entry on rename
---
sys/kern/vfs_cache.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c
index 770c8ebf061b..03bafc75acaa 100644
--- a/sys/kern/vfs_cache.c
+++ b/sys/kern/vfs_cache.c
@@ -367,6 +367,10 @@ static bool __read_frequently cache_fast_revlookup = true;
SYSCTL_BOOL(_vfs, OID_AUTO, cache_fast_revlookup, CTLFLAG_RW,
&cache_fast_revlookup, 0, "");
+static bool __read_mostly cache_rename_add = true;
+SYSCTL_BOOL(_vfs, OID_AUTO, cache_rename_add, CTLFLAG_RW,
+ &cache_rename_add, 0, "");
+
static u_int __exclusive_cache_line neg_cycle;
#define ncneghash 3
@@ -2731,6 +2735,21 @@ cache_vop_rename(struct vnode *fdvp, struct vnode *fvp,
struct vnode *tdvp,
} else {
cache_remove_cnp(tdvp, tcnp);
}
+
+ /*
+ * TODO
+ *
+ * Historically renaming was always purging all revelang entries,
+ * but that's quite wasteful. In particular turns out that in many cases
+ * the target file is immediately accessed after rename, inducing a
cache
+ * miss.
+ *
+ * Recode this to reduce relocking and reuse the existing entry (if any)
+ * instead of just removing it above and allocating a new one here.
+ */
+ if (cache_rename_add) {
+ cache_enter(tdvp, fvp, tcnp);
+ }
}
void
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