Re: git: ef6fcc5e2b07 - main - nfsd: Add VNET_SYSUNINIT() macros for vnet cleanup
- In reply to: Gleb Smirnoff : "Re: git: ef6fcc5e2b07 - main - nfsd: Add VNET_SYSUNINIT() macros for vnet cleanup"
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Date: Wed, 22 Feb 2023 01:43:07 UTC
On 2023-02-21 13:13, Gleb Smirnoff wrote: > On Mon, Feb 20, 2023 at 09:12:41PM +0000, Rick Macklem wrote: > R> nfsd: Add VNET_SYSUNINIT() macros for vnet cleanup > R> > R> Commit ed03776ca7f4 enabled the vnet front end macros. > R> As such, for kernels built with the VIMAGE option will malloc > R> data and initialize locks on a per-vnet basis, typically > R> via a VNET_SYSINIT(). > R> > R> This patch adds VNET_SYSUNINIT() macros to do the frees > R> of the per-vnet malloc'd data and destroys of per-vnet > R> locks. It also removes the mtx_lock/mtx_unlock calls > R> from nfsrvd_cleancache(), since they are not needed. > > In the netinet/netinet6/TCP/UDP we came to a style where we avoid > using IS_DEFAULT_VNET(). Instead doing global and per-vnet init > in the same function: > > static globalfoo; > VNET_DEFINE_STATIC(foobar); > > static void > foo_vnet_init() > { > initialize(V_foobar); > if (IS_DEFAULT_VNET(curvnet)) > initialize(globalfoo); > > } > VNET_SYSINIT(foo_vnet_init, ....) > > We can do a separate init of global state and separate of per-VNET: > > static globalfoo; > static void > foo_init() > { > initialize(globalfoo); > } > SYSINIT(foo_init, ....) > > VNET_DEFINE_STATIC(foobar); > static void > foo_vnet_init() > { > initialize(V_foobar); > } > > This allows to: > > * guarantee that global state is initialized earlier than per-vnet > * separate all global vars from all vnet vars, and keep them together, > easier to maintain > * makes it easier to write VNET_SYSUNINIT() that is complement to > VNET_SYSINIT() > * makes it easier to write SYSUNINIT(), if module is unloadable > * sometimes global SYSINIT cab be avoided, if a static initializer is > enough > > What do you guys think? I'm all for that, just on the first point alone. - Jamie