search for: virt_mb

...= (_r)->req_prod_pvt; \ - wmb(); /* back sees requests /before/ updated producer index */ \ + virt_wmb(); /* back sees requests /before/ updated producer index */ \ (_r)->sring->req_prod = __new; \ - mb(); /* back sees new requests /before/ we check req_event */ \ + virt_mb(); /* back sees new requests /before/ we check req_event */ \ (_notify) = ((RING_IDX)(__new - (_r)->sring->req_event) < \ (RING_IDX)(__new - __old)); \ } while (0) @@ -260,9 +260,9 @@ struct __name##_back_ring { \ #define RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(_r, _notify...

Changes since v1: - replaced my asm-generic patch with an equivalent patch already in tip - add wrappers with virt_ prefix for better code annotation, as suggested by David Miller - dropped XXX in patch names as this makes vger choke, Cc all relevant mailing lists on all patches (not personal email, as the list becomes too long then) I parked this in vhost tree for now, but the

Changes since v1: - replaced my asm-generic patch with an equivalent patch already in tip - add wrappers with virt_ prefix for better code annotation, as suggested by David Miller - dropped XXX in patch names as this makes vger choke, Cc all relevant mailing lists on all patches (not personal email, as the list becomes too long then) I parked this in vhost tree for now, but the

.../include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -12,7 +12,7 @@ * anyone care? * * For virtio_pci on SMP, we don't need to order with respect to MMIO - * accesses through relaxed memory I/O windows, so smp_mb() et al are + * accesses through relaxed memory I/O windows, so virt_mb() et al are * sufficient. * * For using virtio to talk to real devices (eg. other heterogeneous @@ -21,11 +21,10 @@ * actually quite cheap. */ -#ifdef CONFIG_SMP static inline void virtio_mb(bool weak_barriers) { if (weak_barriers) - smp_mb(); + virt_mb(); else mb(); } @@ -3...

...vers/xen/xenbus/xenbus_comms.c index fdb0f33..ecdecce 100644 --- a/drivers/xen/xenbus/xenbus_comms.c +++ b/drivers/xen/xenbus/xenbus_comms.c @@ -123,14 +123,14 @@ int xb_write(const void *data, unsigned len) avail = len; /* Must write data /after/ reading the consumer index. */ - mb(); + virt_mb(); memcpy(dst, data, avail); data += avail; len -= avail; /* Other side must not see new producer until data is there. */ - wmb(); + virt_wmb(); intf->req_prod += avail; /* Implies mb(): other side will see the updated producer. */ @@ -180,14 +180,14 @@ int xb_read(void...

Changes since v2: - extended checkpatch tests for barriers, and added patches teaching it to warn about incorrect usage of barriers (__smp_xxx barriers are for use by asm-generic code only), should help prevent misuse by arch code to address comments by Russell King - patched more instances of xen to use virt_ barriers as suggested by Stefano Stabellini - implemented a 2 byte xchg on sh

Changes since v2: - extended checkpatch tests for barriers, and added patches teaching it to warn about incorrect usage of barriers (__smp_xxx barriers are for use by asm-generic code only), should help prevent misuse by arch code to address comments by Russell King - patched more instances of xen to use virt_ barriers as suggested by Stefano Stabellini - implemented a 2 byte xchg on sh

On Wed, Dec 30, 2015 at 03:46:46PM -0500, David Miller wrote: > From: "Michael S. Tsirkin" <mst at redhat.com> > Date: Wed, 30 Dec 2015 14:58:19 +0200 > > > -. Patch 1 documents the __smp APIs, and explains why they are > > useful for virt > > If virt is doing things like interacting with descriptors that are > shared with a (potentially SMP)

...defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") -#define mb() __sync_synchronize() - -#define smp_mb() mb() -# define dma_rmb() barrier() -# define dma_wmb() barrier() -# define smp_rmb() barrier() -# define smp_wmb() barrier() +#define virt_mb() __sync_synchronize() +#define virt_rmb() barrier() +#define virt_wmb() barrier() +/* Atomic store should be enough, but gcc generates worse code in that case. */ +#define virt_store_mb(var, value) do { \ + typeof(var) virt_store_mb_value = (value); \ + __atomic_exchange(&(var), &virt_sto...

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

On Wed, Dec 30, 2015 at 03:46:46PM -0500, David Miller wrote: > From: "Michael S. Tsirkin" <mst at redhat.com> > Date: Wed, 30 Dec 2015 14:58:19 +0200 > > > -. Patch 1 documents the __smp APIs, and explains why they are > > useful for virt > > If virt is doing things like interacting with descriptors that are > shared with a (potentially SMP)

...defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") -#define mb() __sync_synchronize() - -#define smp_mb() mb() -# define dma_rmb() barrier() -# define dma_wmb() barrier() -# define smp_rmb() barrier() -# define smp_wmb() barrier() +#define virt_mb() __sync_synchronize() +#define virt_rmb() barrier() +#define virt_wmb() barrier() +/* Atomic store should be enough, but gcc generates worse code in that case. */ +#define virt_store_mb(var, value) do { \ + typeof(var) virt_store_mb_value = (value); \ + __atomic_exchange(&(var), &virt_sto...

...3aebe..04d563fc9b95 100644 --- a/tools/virtio/asm/barrier.h +++ b/tools/virtio/asm/barrier.h @@ -1,4 +1,5 @@ /* SPDX-License-Identifier: GPL-2.0 */ +#include <stdlib.h> #if defined(__i386__) || defined(__x86_64__) #define barrier() asm volatile("" ::: "memory") #define virt_mb() __sync_synchronize() -- MST

This is a rebase/resend of earlier patches. I skipped the pure cosmetic patches for now. Mostly this is consolidation earlier changes, removing dead code etc. The important part is the change for allowing a vmbus channel to get callback directly in interrupt mode; this is necessary for NAPI support. Stephen Hemminger (14): vmbus: use kernel bitops for traversing interrupt mask vmbus: drop

This is a rebase/resend of earlier patches. I skipped the pure cosmetic patches for now. Mostly this is consolidation earlier changes, removing dead code etc. The important part is the change for allowing a vmbus channel to get callback directly in interrupt mode; this is necessary for NAPI support. Stephen Hemminger (14): vmbus: use kernel bitops for traversing interrupt mask vmbus: drop

Hi all, Although [smp_]read_barrier_depends() became part of READ_ONCE() in commit 76ebbe78f739 ("locking/barriers: Add implicit smp_read_barrier_depends() to READ_ONCE()"), it still limps on in the Linux memory model with the sinister hope of attracting innocent new users so that it becomes impossible to remove altogether. Let's strike before it's too late: there's only