similar to: [PATCH 0/6] Fixes for meta data acceleration

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V4: - switch to use spinlock synchronize MMU notifier with accessors Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V4: - switch to use spinlock synchronize MMU notifier with accessors Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the range is overlapped with metadata Jason Wang (9):

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V3: - remove the unnecessary patch Changes from V2: - use seqlck helper to synchronize MMU notifier with vhost worker Changes from V1: - try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the

Hi all: This series try to fix several issues introduced by meta data accelreation series. Please review. Changes from V1: - Try not use RCU to syncrhonize MMU notifier with vhost worker - set dirty pages after no readers - return -EAGAIN only when we find the range is overlapped with metadata Jason Wang (9): vhost: don't set uaddr for invalid address vhost: validate MMU notifier

Hi: Per request from Michael and Jason, the metadata accelreation is reverted in this version and rework in next version. Please review. Thanks Jason Wang (2): Revert "vhost: access vq metadata through kernel virtual address" vhost: re-introducing metadata acceleration through kernel virtual address drivers/vhost/vhost.c | 202 +++++++++++++++++++++++++-----------------

Hi: Per request from Michael and Jason, the metadata accelreation is reverted in this version and rework in next version. Please review. Thanks Jason Wang (2): Revert "vhost: access vq metadata through kernel virtual address" vhost: re-introducing metadata acceleration through kernel virtual address drivers/vhost/vhost.c | 202 +++++++++++++++++++++++++-----------------

On Thu, Sep 05, 2019 at 08:27:36PM +0800, Jason Wang wrote: > This is a rework on the commit 7f466032dc9e ("vhost: access vq > metadata through kernel virtual address"). > > It was noticed that the copy_to/from_user() friends that was used to > access virtqueue metdata tends to be very expensive for dataplane > implementation like vhost since it involves lots of

On Thu, Sep 05, 2019 at 08:27:36PM +0800, Jason Wang wrote: > This is a rework on the commit 7f466032dc9e ("vhost: access vq > metadata through kernel virtual address"). > > It was noticed that the copy_to/from_user() friends that was used to > access virtqueue metdata tends to be very expensive for dataplane > implementation like vhost since it involves lots of

On Tue, Jul 23, 2019 at 03:57:14AM -0400, Jason Wang wrote: > The return value of mmu_notifier_register() is not checked in > vhost_vring_set_num_addr(). This will cause an out of sync between mm > and MMU notifier thus a double free. To solve this, introduce a > boolean flag to track whether MMU notifier is registered and only do > unregistering when it was true. > >

On Thu, Sep 05, 2019 at 08:27:35PM +0800, Jason Wang wrote: > It was reported that metadata acceleration introduces several issues, > so this patch reverts commit ff466032dc9e5a61217f22ea34b2df932786bbfc, > 73f628ec9e6bcc45b77c53fe6d0c0ec55eaf82af and > 0b4a7092ffe568a55bf8f3cefdf79ff666586d91. > > We will rework it on the next version. > > Cc: Jason Gunthorpe <jgg at

On Tue, Jul 23, 2019 at 03:57:17AM -0400, Jason Wang wrote: > We don't mark dirty pages if the map was teared down outside MMU > notifier. This will lead untracked dirty pages. Fixing by marking > dirty pages during map uninit. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual

On Tue, Jul 23, 2019 at 03:57:17AM -0400, Jason Wang wrote: > We don't mark dirty pages if the map was teared down outside MMU > notifier. This will lead untracked dirty pages. Fixing by marking > dirty pages during map uninit. > > Reported-by: Michael S. Tsirkin <mst at redhat.com> > Fixes: 7f466032dc9e ("vhost: access vq metadata through kernel virtual

This series tries to access virtqueue metadata through kernel virtual address instead of copy_user() friends since they had too much overheads like checks, spec barriers or even hardware feature toggling. This is done through setup kernel address through direct mapping and co-opreate VM management with MMU notifiers. Test shows about 23% improvement on TX PPS. TCP_STREAM doesn't see obvious

Hi: This series tries to access virtqueue metadata through kernel virtual address instead of copy_user() friends since they had too much overheads like checks, spec barriers or even hardware feature toggling like SMAP. This is done through setup kernel address through direct mapping and co-opreate VM management with MMU notifiers. Test shows about 23% improvement on TX PPS. TCP_STREAM

Hi: This series tries to access virtqueue metadata through kernel virtual address instead of copy_user() friends since they had too much overheads like checks, spec barriers or even hardware feature toggling like SMAP. This is done through setup kernel address through direct mapping and co-opreate VM management with MMU notifiers. Test shows about 23% improvement on TX PPS. TCP_STREAM

Clang warns: drivers/vhost/vhost.c:2085:5: warning: macro expansion producing 'defined' has undefined behavior [-Wexpansion-to-defined] #if VHOST_ARCH_CAN_ACCEL_UACCESS ^ drivers/vhost/vhost.h:98:38: note: expanded from macro 'VHOST_ARCH_CAN_ACCEL_UACCESS' #define VHOST_ARCH_CAN_ACCEL_UACCESS defined(CONFIG_MMU_NOTIFIER) && \

Clang warns: drivers/vhost/vhost.c:2085:5: warning: macro expansion producing 'defined' has undefined behavior [-Wexpansion-to-defined] #if VHOST_ARCH_CAN_ACCEL_UACCESS ^ drivers/vhost/vhost.h:98:38: note: expanded from macro 'VHOST_ARCH_CAN_ACCEL_UACCESS' #define VHOST_ARCH_CAN_ACCEL_UACCESS defined(CONFIG_MMU_NOTIFIER) && \

On Wed, Jul 31, 2019 at 04:46:53AM -0400, Jason Wang wrote: > We used to use RCU to synchronize MMU notifier with worker. This leads > calling synchronize_rcu() in invalidate_range_start(). But on a busy > system, there would be many factors that may slow down the > synchronize_rcu() which makes it unsuitable to be called in MMU > notifier. > > A solution is SRCU but its