Date: Fri, 29 Jan 2021 14:11:05 +1100 From: Kubilay Kocak <koobs@FreeBSD.org> To: Mateusz Guzik <mjguzik@gmail.com>, 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: <6be9d1bd-5180-e4f0-5f52-c50fdefbc5ec@FreeBSD.org> In-Reply-To: <CAGudoHF1fVLfA=D%2BUiEJE6p0DRDQitqGXsEuyKW8_Mmk%2B7Ws_g@mail.gmail.com> References: <202101231810.10NIAKXd018767@gitrepo.freebsd.org> <CAPjTQNF9858cJY1S4_q4_fak6r3AGQU3_23u=gA5LeqV_eX64g@mail.gmail.com> <CAGudoHF1fVLfA=D%2BUiEJE6p0DRDQitqGXsEuyKW8_Mmk%2B7Ws_g@mail.gmail.com>
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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.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" >>> >> > > Could we: description: "QA/Testing (temporary) tunable: <description>" ?
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