Date: Sat, 23 Jan 2021 21:22:12 +0100 From: Mateusz Guzik <mjguzik@gmail.com> To: Oliver Pinter <oliver.pntr@gmail.com> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@freebsd.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@freebsd.org> Subject: Re: git: 02ec31bdf60f - main - cache: add back target entry on rename Message-ID: <CAGudoHF1fVLfA=D%2BUiEJE6p0DRDQitqGXsEuyKW8_Mmk%2B7Ws_g@mail.gmail.com> In-Reply-To: <CAPjTQNF9858cJY1S4_q4_fak6r3AGQU3_23u=gA5LeqV_eX64g@mail.gmail.com> References: <202101231810.10NIAKXd018767@gitrepo.freebsd.org> <CAPjTQNF9858cJY1S4_q4_fak6r3AGQU3_23u=gA5LeqV_eX64g@mail.gmail.com>
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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.pntr@gmail.com> wrote: > On Saturday, January 23, 2021, Mateusz Guzik <mjg@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 <mjg@FreeBSD.org> >> AuthorDate: 2021-01-23 17:21:42 +0000 >> Commit: Mateusz Guzik <mjg@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 >> _______________________________________________ >> dev-commits-src-all@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/dev-commits-src-all >> To unsubscribe, send any mail to "dev-commits-src-all- >> unsubscribe@freebsd.org" >> > -- Mateusz Guzik <mjguzik gmail.com>
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