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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 09/18] mini-os: remove per-fd evtchn limit
On Thu, 2012-01-12 at 23:35 +0000, Daniel De Graaf wrote:
> From: Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>
>
> Changes the minios evtchn implementation to use a list instead of an array.
> This allows it to grow as necessary to support any number of ports.
> Unfortunately, it's still limited by NR_EVS in events.c.
NR_EVS is 1024 which, IIRC, is the actual ABI limit for a 32 bit domain.
In principal we could make this 4096 for a 64 bit stub domain but I
guess we only need 1 evtchn per domain plus perhaps a couple of
incidental global ones (e.g. console, VIRQ_mumble) and ~1000+ domains is
more than enough for any current system.
> Signed-off-by: Diego Ongaro <diego.ongaro@xxxxxxxxxx>
> Signed-off-by: Alex Zeffertt <alex.zeffertt@xxxxxxxxxxxxx>
> Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
> extras/mini-os/include/lib.h | 16 +++---
> tools/libxc/xc_minios.c | 139
> ++++++++++++++++++++++--------------------
> 2 files changed, 81 insertions(+), 74 deletions(-)
>
> diff --git a/extras/mini-os/include/lib.h b/extras/mini-os/include/lib.h
> index bd3eeaf..12070c3 100644
> --- a/extras/mini-os/include/lib.h
> +++ b/extras/mini-os/include/lib.h
> @@ -53,6 +53,7 @@
> #include <xen/xen.h>
> #include <xen/event_channel.h>
> #include "gntmap.h"
> +#include "list.h"
>
> #ifdef HAVE_LIBC
> #include <stdio.h>
> @@ -143,7 +144,12 @@ enum fd_type {
> FTYPE_SAVEFILE,
> };
>
> -#define MAX_EVTCHN_PORTS 16
> +struct evtchn_port_info {
> + struct minios_list_head list;
> + evtchn_port_t port;
> + unsigned long pending;
> + int bound;
> +};
>
> extern struct file {
> enum fd_type type;
> @@ -158,13 +164,7 @@ extern struct file {
> off_t offset;
> } file;
> struct {
> - /* To each event channel FD is associated a series of ports which
> - * wakes select for this FD. */
> - struct {
> - evtchn_port_t port;
> - unsigned long pending;
> - int bound;
> - } ports[MAX_EVTCHN_PORTS];
> + struct minios_list_head ports;
> } evtchn;
> struct gntmap gntmap;
> struct {
> diff --git a/tools/libxc/xc_minios.c b/tools/libxc/xc_minios.c
> index 8bbfd18..29cce63 100644
> --- a/tools/libxc/xc_minios.c
> +++ b/tools/libxc/xc_minios.c
> @@ -210,15 +210,34 @@ static struct xc_osdep_ops minios_privcmd_ops = {
> },
> };
>
> +
> +/* XXX Note: This is not threadsafe */
> +static struct evtchn_port_info* port_alloc(int fd) {
> + struct evtchn_port_info *port_info;
> + port_info = malloc(sizeof(struct evtchn_port_info));
> + if (port_info == NULL)
> + return NULL;
> + port_info->pending = 0;
> + port_info->port = -1;
> + port_info->bound = 0;
> +
> + minios_list_add(&port_info->list, &files[fd].evtchn.ports);
> + return port_info;
> +}
> +
> +static void port_dealloc(struct evtchn_port_info *port_info) {
> + if (port_info->bound)
> + unbind_evtchn(port_info->port);
> + minios_list_del(&port_info->list);
> + free(port_info);
> +}
> +
> static xc_osdep_handle minios_evtchn_open(xc_evtchn *xce)
> {
> - int fd = alloc_fd(FTYPE_EVTCHN), i;
> + int fd = alloc_fd(FTYPE_EVTCHN);
> if ( fd == -1 )
> return XC_OSDEP_OPEN_ERROR;
> - for (i = 0; i < MAX_EVTCHN_PORTS; i++) {
> - files[fd].evtchn.ports[i].port = -1;
> - files[fd].evtchn.ports[i].bound = 0;
> - }
> + MINIOS_INIT_LIST_HEAD(&files[fd].evtchn.ports);
> printf("evtchn_open() -> %d\n", fd);
> return (xc_osdep_handle)fd;
> }
> @@ -231,10 +250,10 @@ static int minios_evtchn_close(xc_evtchn *xce,
> xc_osdep_handle h)
>
> void minios_evtchn_close_fd(int fd)
> {
> - int i;
> - for (i = 0; i < MAX_EVTCHN_PORTS; i++)
> - if (files[fd].evtchn.ports[i].bound)
> - unbind_evtchn(files[fd].evtchn.ports[i].port);
> + struct evtchn_port_info *port_info, *tmp;
> + minios_list_for_each_entry_safe(port_info, tmp, &files[fd].evtchn.ports,
> list)
> + port_dealloc(port_info);
> +
> files[fd].type = FTYPE_NONE;
> }
>
> @@ -256,35 +275,21 @@ static int minios_evtchn_notify(xc_evtchn *xce,
> xc_osdep_handle h, evtchn_port_t
> return ret;
> }
>
> -/* XXX Note: This is not threadsafe */
> -static int port_alloc(int fd) {
> - int i;
> - for (i= 0; i < MAX_EVTCHN_PORTS; i++)
> - if (files[fd].evtchn.ports[i].port == -1)
> - break;
> - if (i == MAX_EVTCHN_PORTS) {
> - printf("Too many ports in xc handle\n");
> - errno = EMFILE;
> - return -1;
> - }
> - files[fd].evtchn.ports[i].pending = 0;
> - return i;
> -}
> -
> static void evtchn_handler(evtchn_port_t port, struct pt_regs *regs, void
> *data)
> {
> int fd = (int)(intptr_t)data;
> - int i;
> + struct evtchn_port_info *port_info;
> assert(files[fd].type == FTYPE_EVTCHN);
> mask_evtchn(port);
> - for (i= 0; i < MAX_EVTCHN_PORTS; i++)
> - if (files[fd].evtchn.ports[i].port == port)
> - break;
> - if (i == MAX_EVTCHN_PORTS) {
> - printk("Unknown port for handle %d\n", fd);
> - return;
> + minios_list_for_each_entry(port_info, &files[fd].evtchn.ports, list) {
> + if (port_info->port == port)
> + goto found;
> }
> - files[fd].evtchn.ports[i].pending = 1;
> + printk("Unknown port for handle %d\n", fd);
> + return;
> +
> + found:
> + port_info->pending = 1;
> files[fd].read = 1;
> wake_up(&event_queue);
> }
> @@ -292,12 +297,13 @@ static void evtchn_handler(evtchn_port_t port, struct
> pt_regs *regs, void *data)
> static evtchn_port_or_error_t minios_evtchn_bind_unbound_port(xc_evtchn
> *xce, xc_osdep_handle h, int domid)
> {
> int fd = (int)h;
> - int ret, i;
> + struct evtchn_port_info *port_info;
> + int ret;
> evtchn_port_t port;
>
> assert(get_current() == main_thread);
> - i = port_alloc(fd);
> - if (i == -1)
> + port_info = port_alloc(fd);
> + if (port_info == NULL)
> return -1;
>
> printf("xc_evtchn_bind_unbound_port(%d)", domid);
> @@ -305,11 +311,12 @@ static evtchn_port_or_error_t
> minios_evtchn_bind_unbound_port(xc_evtchn *xce, xc
> printf(" = %d\n", ret);
>
> if (ret < 0) {
> + port_dealloc(port_info);
> errno = -ret;
> return -1;
> }
> - files[fd].evtchn.ports[i].bound = 1;
> - files[fd].evtchn.ports[i].port = port;
> + port_info->bound = 1;
> + port_info->port = port;
> unmask_evtchn(port);
> return port;
> }
> @@ -318,12 +325,13 @@ static evtchn_port_or_error_t
> minios_evtchn_bind_interdomain(xc_evtchn *xce, xc_
> evtchn_port_t remote_port)
> {
> int fd = (int)h;
> + struct evtchn_port_info *port_info;
> evtchn_port_t local_port;
> - int ret, i;
> + int ret;
>
> assert(get_current() == main_thread);
> - i = port_alloc(fd);
> - if (i == -1)
> + port_info = port_alloc(fd);
> + if (port_info == NULL)
> return -1;
>
> printf("xc_evtchn_bind_interdomain(%d, %"PRId32")", domid, remote_port);
> @@ -331,11 +339,12 @@ static evtchn_port_or_error_t
> minios_evtchn_bind_interdomain(xc_evtchn *xce, xc_
> printf(" = %d\n", ret);
>
> if (ret < 0) {
> + port_dealloc(port_info);
> errno = -ret;
> return -1;
> }
> - files[fd].evtchn.ports[i].bound = 1;
> - files[fd].evtchn.ports[i].port = local_port;
> + port_info->bound = 1;
> + port_info->port = local_port;
> unmask_evtchn(local_port);
> return local_port;
> }
> @@ -343,42 +352,40 @@ static evtchn_port_or_error_t
> minios_evtchn_bind_interdomain(xc_evtchn *xce, xc_
> static int minios_evtchn_unbind(xc_evtchn *xce, xc_osdep_handle h,
> evtchn_port_t port)
> {
> int fd = (int)h;
> - int i;
> - for (i = 0; i < MAX_EVTCHN_PORTS; i++)
> - if (files[fd].evtchn.ports[i].port == port) {
> - files[fd].evtchn.ports[i].port = -1;
> - break;
> - }
> - if (i == MAX_EVTCHN_PORTS) {
> - printf("Warning: couldn't find port %"PRId32" for xc handle %x\n",
> port, fd);
> - errno = -EINVAL;
> - return -1;
> + struct evtchn_port_info *port_info;
> +
> + minios_list_for_each_entry(port_info, &files[fd].evtchn.ports, list) {
> + if (port_info->port == port) {
> + port_dealloc(port_info);
> + return 0;
> + }
> }
> - files[fd].evtchn.ports[i].bound = 0;
> - unbind_evtchn(port);
> - return 0;
> + printf("Warning: couldn't find port %"PRId32" for xc handle %x\n", port,
> fd);
> + errno = -EINVAL;
> + return -1;
> }
>
> static evtchn_port_or_error_t minios_evtchn_bind_virq(xc_evtchn *xce,
> xc_osdep_handle h, unsigned int virq)
> {
> int fd = (int)h;
> + struct evtchn_port_info *port_info;
> evtchn_port_t port;
> - int i;
>
> assert(get_current() == main_thread);
> - i = port_alloc(fd);
> - if (i == -1)
> + port_info = port_alloc(fd);
> + if (port_info == NULL)
> return -1;
>
> printf("xc_evtchn_bind_virq(%d)", virq);
> port = bind_virq(virq, evtchn_handler, (void*)(intptr_t)fd);
>
> if (port < 0) {
> + port_dealloc(port_info);
> errno = -port;
> return -1;
> }
> - files[fd].evtchn.ports[i].bound = 1;
> - files[fd].evtchn.ports[i].port = port;
> + port_info->bound = 1;
> + port_info->port = port;
> unmask_evtchn(port);
> return port;
> }
> @@ -386,18 +393,18 @@ static evtchn_port_or_error_t
> minios_evtchn_bind_virq(xc_evtchn *xce, xc_osdep_h
> static evtchn_port_or_error_t minios_evtchn_pending(xc_evtchn *xce,
> xc_osdep_handle h)
> {
> int fd = (int)h;
> - int i;
> + struct evtchn_port_info *port_info;
> unsigned long flags;
> evtchn_port_t ret = -1;
>
> local_irq_save(flags);
> files[fd].read = 0;
> - for (i = 0; i < MAX_EVTCHN_PORTS; i++) {
> - evtchn_port_t port = files[fd].evtchn.ports[i].port;
> - if (port != -1 && files[fd].evtchn.ports[i].pending) {
> +
> + minios_list_for_each_entry(port_info, &files[fd].evtchn.ports, list) {
> + if (port_info->port != -1 && port_info->pending) {
> if (ret == -1) {
> - ret = port;
> - files[fd].evtchn.ports[i].pending = 0;
> + ret = port_info->port;
> + port_info->pending = 0;
> } else {
> files[fd].read = 1;
> break;
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