Date: Tue, 4 Aug 2015 23:22:02 +0000 From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: "Jason A. Harmening" <jah@FreeBSD.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r286296 - in head/sys: amd64/amd64 arm/arm arm/include arm64/arm64 i386/i386 i386/include mips/mips powerpc/aim powerpc/booke powerpc/include powerpc/powerpc sparc64/include sparc64/spa... Message-ID: <C80D87EE-2429-4FD8-8738-F6EF722A7FC4@FreeBSD.org> In-Reply-To: <201508041946.t74JkExD070238@repo.freebsd.org> References: <201508041946.t74JkExD070238@repo.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> On 04 Aug 2015, at 19:46 , Jason A. Harmening <jah@FreeBSD.org> wrote: >=20 > Author: jah > Date: Tue Aug 4 19:46:13 2015 > New Revision: 286296 > URL: https://svnweb.freebsd.org/changeset/base/286296 >=20 > Log: > Add two new pmap functions: > vm_offset_t pmap_quick_enter_page(vm_page_t m) > void pmap_quick_remove_page(vm_offset_t kva) >=20 > These will create and destroy a temporary, CPU-local KVA mapping of a = specified page. >=20 > Guarantees: > --Will not sleep and will not fail. > --Safe to call under a non-sleepable lock or from an ithread >=20 > Restrictions: > --Not guaranteed to be safe to call from an interrupt filter or under = a spin mutex on all platforms > --Current implementation does not guarantee more than one page of = mapping space across all platforms. MI code should not make nested calls = to pmap_quick_enter_page. > --MI code should not perform locking while holding onto a mapping = created by pmap_quick_enter_page >=20 > The idea is to use this in busdma, for bounce buffer copies as well = as virtually-indexed cache maintenance on mips and arm. >=20 > NOTE: the non-i386, non-amd64 implementations of these functions = still need review and testing. Most of this description should go into a section 9 man page rather than = the commit message ;-) /bz
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?C80D87EE-2429-4FD8-8738-F6EF722A7FC4>