similar to: lazy mmu and interrupts

Is pte_offset_map allowed to happen within lazy mmu? I presume not, because you definitely don't want the mapping pte update to be deferred. Or, more specifically, is kunmap_atomic ever allowed within lazy mmu? I'm looking at kpte_clear_flush; I've already got a patch which turns this into a pv_op, along with a Xen implementation. But I think its probably an excess pv_op for a

Is pte_offset_map allowed to happen within lazy mmu? I presume not, because you definitely don't want the mapping pte update to be deferred. Or, more specifically, is kunmap_atomic ever allowed within lazy mmu? I'm looking at kpte_clear_flush; I've already got a patch which turns this into a pv_op, along with a Xen implementation. But I think its probably an excess pv_op for a

I recently sent off a fix for lazy vmalloc faults which can happen under = paravirt when lazy mode is enabled. Unfortunately, I jumped the gun a = bit on fixing this. I neglected to notice that since the new call to = flush the MMU update queue is called from the page fault handler, it can = be pre-empted. Both VMI and Xen use per-cpu variables to track lazy = mode state, as all previous

I recently sent off a fix for lazy vmalloc faults which can happen under = paravirt when lazy mode is enabled. Unfortunately, I jumped the gun a = bit on fixing this. I neglected to notice that since the new call to = flush the MMU update queue is called from the page fault handler, it can = be pre-empted. Both VMI and Xen use per-cpu variables to track lazy = mode state, as all previous

Hi Andi, This is a set of updates for the firstfloor patch queue. Quick rundown: revert-mm-x86_64-mm-account-for-module-percpu-space-separately-from-kernel-percpu.patch separate-module-percpu-space.patch Update the module percpu accounting patch fix-ff-allow-percpu-variables-to-be-page-aligned.patch Make sure the percpu memory allocation is page-aligned

Hi Andi, This is a set of updates for the firstfloor patch queue. Quick rundown: revert-mm-x86_64-mm-account-for-module-percpu-space-separately-from-kernel-percpu.patch separate-module-percpu-space.patch Update the module percpu accounting patch fix-ff-allow-percpu-variables-to-be-page-aligned.patch Make sure the percpu memory allocation is page-aligned

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

Hi all, [ Change since last post: change name to ptep_modify_prot_, on the grounds that it isn't really a general pte-modification interface. ] This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native),

Hi Zach, I'm wondering what the interface requirements of set_pte_at()'s "addr" and "ptep" args are. I presume that in general the ptep points to the pte entry which corresponds to the vaddr, but is this necessarily the case? For example, it is valid to pass a non-highmem page kmap_atomic(), which will simply return a direct pointer to the page. kunmap_atomic()

Hi Zach, I'm wondering what the interface requirements of set_pte_at()'s "addr" and "ptep" args are. I presume that in general the ptep points to the pte entry which corresponds to the vaddr, but is this necessarily the case? For example, it is valid to pass a non-highmem page kmap_atomic(), which will simply return a direct pointer to the page. kunmap_atomic()

Hi Andi, This series of patches updates paravirt_ops in various ways. Some of the changes are plain cleanups and improvements, and some add some interfaces necessary for Xen. The brief overview: add-MAINTAINERS.patch - obvious remove-CONFIG_DEBUG_PARAVIRT.patch - no longer needed paravirt-nop.patch - mark nop operations consistently paravirt-pte-accessors.patch - operations to pack/unpack

Hi Andi, This series of patches updates paravirt_ops in various ways. Some of the changes are plain cleanups and improvements, and some add some interfaces necessary for Xen. The brief overview: add-MAINTAINERS.patch - obvious remove-CONFIG_DEBUG_PARAVIRT.patch - no longer needed paravirt-nop.patch - mark nop operations consistently paravirt-pte-accessors.patch - operations to pack/unpack

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

Hi all, This little series adds a new transaction-like abstraction for doing RMW updates to a pte, hooks it into paravirt_ops, and then makes use of it in Xen. The basic problem is that mprotect is very slow under Xen (up to 50x slower than native), primarily because of the ptent = ptep_get_and_clear(mm, addr, pte); ptent = pte_modify(ptent, newprot); /* ... */ set_pte_at(mm, addr, pte,

Hi Andi, Here's a repost of the paravirt_ops update series I posted the other day. Since then, I found a few potential bugs with patching clobbering, cleaned up and documented paravirt.h and the patching machinery. Overview: add-MAINTAINERS.patch obvious remove-CONFIG_DEBUG_PARAVIRT.patch No longer meaningful or needed. paravirt-nop.patch Clean up nop paravirt_ops functions, mainly to

Hi Andi, Here's a repost of the paravirt_ops update series I posted the other day. Since then, I found a few potential bugs with patching clobbering, cleaned up and documented paravirt.h and the patching machinery. Overview: add-MAINTAINERS.patch obvious remove-CONFIG_DEBUG_PARAVIRT.patch No longer meaningful or needed. paravirt-nop.patch Clean up nop paravirt_ops functions, mainly to

Hello Jeson, On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote: > Just to make sure I understand here. For boosting through huge TLB, do > you mean we can do that in the future (e.g by mapping more userspace > pages to kenrel) or it can be done by this series (only about three 4K > pages were vmapped per virtqueue)? When I answered about the advantages of mmu notifier and

Hello Jeson, On Fri, Mar 08, 2019 at 04:50:36PM +0800, Jason Wang wrote: > Just to make sure I understand here. For boosting through huge TLB, do > you mean we can do that in the future (e.g by mapping more userspace > pages to kenrel) or it can be done by this series (only about three 4K > pages were vmapped per virtqueue)? When I answered about the advantages of mmu notifier and