| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20100428180503.GJ18168@amt.cnet> Date: Wed, 28 Apr 2010 15:05:03 -0300 From: Marcelo Tosatti <mtosatti@...hat.com> To: Lai Jiangshan <laijs@...fujitsu.com> Cc: Avi Kivity <avi@...hat.com>, LKML <linux-kernel@...r.kernel.org>, kvm@...r.kernel.org Subject: Re: [PATCH] kvm mmu: reduce 50% memory usage On Wed, Apr 28, 2010 at 07:57:01PM +0800, Lai Jiangshan wrote: > > I think users will enable tdp when their hardwares support ept or npt. > This patch can reduce about 50% kvm mmu memory usage for they. > > This simple patch use the fact that: > > When sp->role.direct is set, sp->gfns does not contain any essential > information, leaf sptes reachable from this sp are for a continuate > guest physical memory range(a linear range). > So sp->gfns[i](if it was set) equals to sp->gfn + i. (PT_PAGE_TABLE_LEVEL) > Obviously, it is not essential information, we can calculate it when need. > > It means we don't need sp->gfns when sp->role.direct=1, > Thus we can save one page usage for every kvm_mmu_page. > > Note: > Access to sp->gfns must be wrapped by kvm_mmu_page_get_gfn() > or kvm_mmu_page_set_gfn(). > It is only exposed in FNAME(sync_page). > > Signed-off-by: Lai Jiangshan <laijs@...fujitsu.com> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists