Re: Page Eviction Algorithm
On Thu, Oct 28, 2010 at 1:45 AM, Avi Kivity wrote: >> Does this MMU invalidation has to do something with the EPT (Extended >> Page Table) > > No > >> and instruction INVEPT? > > No, (though INVEPT has to be run as part of this operation, via > kvm_flush_remote_tlbs). Thanks a lot Avi for your help. I would look at the code and do my study. I would ask clarification whenever I need help. > > -- -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
On 10/26/2010 05:08 PM, Prasad Joshi wrote: >>> >>> Can you please suggest me something that would add value to KVM? >>> >> >> O(1) write protection (on the TODO page) is interesting and important. It's >> difficult, so you may want to start with O(1) invalidation. > > I am not sure if I can understand what exactly is a MMU invalidation. > Is it cache invalidation or TLB invalidation? Can you please > elaborate. I am really sorry if I am asking a silly question. Does this MMU invalidation has to do something with the EPT (Extended Page Table) No and instruction INVEPT? No, (though INVEPT has to be run as part of this operation, via kvm_flush_remote_tlbs). -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
On 10/26/2010 03:31 PM, Prasad Joshi wrote: On Tue, Oct 26, 2010 at 2:07 PM, Avi Kivity wrote: >On 10/26/2010 12:42 PM, Prasad Joshi wrote: >> >> Thanks a lot for your reply. >> >> On Tue, Oct 26, 2010 at 11:31 AM, Avi Kivitywrote: >> > On 10/26/2010 11:19 AM, Prasad Joshi wrote: >> >> >> >>Hi All, >> >> >> >>I was just going over TODO list on KVM page. In MMU related TODO I saw >> >>only page eviction algorithm currently implemented is FIFO. >> >> >> >>Is it really the case? >> > >> >Yes. >> > >> >>If yes I would like to work on it. Can someone >> >>let me know the place where the FIFO code is implemented? >> > >> >Look at the code that touches mmu_active_list. >> > >> >FWIW improving the algorithm is not critically important. It's rare >> > that >> >mmu shadow pages need to be evicted. >> >> I would be doing a University project on Virtualization. I would like >> to work on Linux kernel and KVM. I was looking over the TODO list on >> KVM wiki. >> >> Can you please suggest me something that would add value to KVM? >> > > O(1) write protection (on the TODO page) is interesting and important. It's > difficult, so you may want to start with O(1) invalidation. I am not sure if I can understand what exactly is a MMU invalidation. Is it cache invalidation or TLB invalidation? Can you please elaborate. I am really sorry if I am asking a silly question. Invalidation of all shadow page tables. The current code which does this is in kvm_mmu_zap_all(). -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
>>> >>> Can you please suggest me something that would add value to KVM? >>> >> >> O(1) write protection (on the TODO page) is interesting and important. It's >> difficult, so you may want to start with O(1) invalidation. > > I am not sure if I can understand what exactly is a MMU invalidation. > Is it cache invalidation or TLB invalidation? Can you please > elaborate. I am really sorry if I am asking a silly question. Does this MMU invalidation has to do something with the EPT (Extended Page Table) and instruction INVEPT? Please clarify. > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
On Tue, Oct 26, 2010 at 2:07 PM, Avi Kivity wrote: > On 10/26/2010 12:42 PM, Prasad Joshi wrote: >> >> Thanks a lot for your reply. >> >> On Tue, Oct 26, 2010 at 11:31 AM, Avi Kivity wrote: >> > On 10/26/2010 11:19 AM, Prasad Joshi wrote: >> >> >> >> Hi All, >> >> >> >> I was just going over TODO list on KVM page. In MMU related TODO I saw >> >> only page eviction algorithm currently implemented is FIFO. >> >> >> >> Is it really the case? >> > >> > Yes. >> > >> >> If yes I would like to work on it. Can someone >> >> let me know the place where the FIFO code is implemented? >> > >> > Look at the code that touches mmu_active_list. >> > >> > FWIW improving the algorithm is not critically important. It's rare >> > that >> > mmu shadow pages need to be evicted. >> >> I would be doing a University project on Virtualization. I would like >> to work on Linux kernel and KVM. I was looking over the TODO list on >> KVM wiki. >> >> Can you please suggest me something that would add value to KVM? >> > > O(1) write protection (on the TODO page) is interesting and important. It's > difficult, so you may want to start with O(1) invalidation. I am not sure if I can understand what exactly is a MMU invalidation. Is it cache invalidation or TLB invalidation? Can you please elaborate. I am really sorry if I am asking a silly question. > > -- > error compiling committee.c: too many arguments to function > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
On 10/26/2010 12:42 PM, Prasad Joshi wrote: Thanks a lot for your reply. On Tue, Oct 26, 2010 at 11:31 AM, Avi Kivity wrote: >On 10/26/2010 11:19 AM, Prasad Joshi wrote: >> >> Hi All, >> >> I was just going over TODO list on KVM page. In MMU related TODO I saw >> only page eviction algorithm currently implemented is FIFO. >> >> Is it really the case? > > Yes. > >> If yes I would like to work on it. Can someone >> let me know the place where the FIFO code is implemented? > > Look at the code that touches mmu_active_list. > > FWIW improving the algorithm is not critically important. It's rare that > mmu shadow pages need to be evicted. I would be doing a University project on Virtualization. I would like to work on Linux kernel and KVM. I was looking over the TODO list on KVM wiki. Can you please suggest me something that would add value to KVM? O(1) write protection (on the TODO page) is interesting and important. It's difficult, so you may want to start with O(1) invalidation. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
Thanks a lot for your reply. On Tue, Oct 26, 2010 at 11:31 AM, Avi Kivity wrote: > On 10/26/2010 11:19 AM, Prasad Joshi wrote: >> >> Hi All, >> >> I was just going over TODO list on KVM page. In MMU related TODO I saw >> only page eviction algorithm currently implemented is FIFO. >> >> Is it really the case? > > Yes. > >> If yes I would like to work on it. Can someone >> let me know the place where the FIFO code is implemented? > > Look at the code that touches mmu_active_list. > > FWIW improving the algorithm is not critically important. It's rare that > mmu shadow pages need to be evicted. I would be doing a University project on Virtualization. I would like to work on Linux kernel and KVM. I was looking over the TODO list on KVM wiki. Can you please suggest me something that would add value to KVM? > > -- > error compiling committee.c: too many arguments to function > > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Page Eviction Algorithm
On 10/26/2010 11:19 AM, Prasad Joshi wrote: Hi All, I was just going over TODO list on KVM page. In MMU related TODO I saw only page eviction algorithm currently implemented is FIFO. Is it really the case? Yes. If yes I would like to work on it. Can someone let me know the place where the FIFO code is implemented? Look at the code that touches mmu_active_list. FWIW improving the algorithm is not critically important. It's rare that mmu shadow pages need to be evicted. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Page Eviction Algorithm
Hi All, I was just going over TODO list on KVM page. In MMU related TODO I saw only page eviction algorithm currently implemented is FIFO. Is it really the case? If yes I would like to work on it. Can someone let me know the place where the FIFO code is implemented? Thanks and Regards, Prasad -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
