Date: Mon, 1 Feb 2021 12:40:35 GMT From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: ba0689009b71 - stable/13 - cache: add back target entry on rename Message-ID: <202102011240.111CeZjh094699@gitrepo.freebsd.org>
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The branch stable/13 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=ba0689009b712c558f4ec2b28202a4e45c5bab91 commit ba0689009b712c558f4ec2b28202a4e45c5bab91 Author: Mateusz Guzik <mjg@FreeBSD.org> AuthorDate: 2021-01-23 17:21:42 +0000 Commit: Mateusz Guzik <mjg@FreeBSD.org> CommitDate: 2021-02-01 12:39:15 +0000 cache: add back target entry on rename (cherry picked from commit 02ec31bdf60fa3a8530544cb3c8c4ec1df6cde0d) --- 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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