On 24/01/2021 7:22 am, Mateusz Guzik wrote:
The sysctl at hand is temporary in case someone reports trouble --
then they can flip it. I don't expect it to survive more than a month.
On 1/23/21, Oliver Pinter <oliver.p...@gmail.com> wrote:
On Saturday, January 23, 2021, Mateusz Guzik <m...@freebsd.org> wrote:
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, "");
It would be really if the description were filled with proper info.
+
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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Could we:
description: "QA/Testing (temporary) tunable: <description>" ?
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