clockintr(9): clock interrupt scheduler
Hi, This patch adds a machine-indepent clock interrupt scheduler to the kernel. It is called clockintr(9). The code is featureful enough to emulate most of what the machine-dependent clock interrupt code is doing across all all platforms. This is a first step toward what some systems call "tickless" kernel operation. I am looking for OKs to commit this piece and continue working on it in the tree. The next step will entail switching every platform over to using clockintr(9) while refining it to address problems found in the process. The attached patch is only the MI portion. The code is conditionally compiled when __HAVE_CLOCKINTR is set, so this patch will not affect behavior on any platform yet. The rest of this mail enumerates why we want this and a brief description of how it works. First, "why do we want this?": 1. An MI clock interrupt scheduler will make it possible to provide clock interrupt control to other MI parts of the kernel. For example, if the timeout(9) layer can steer the clock interrupt it can dramatically reduce timeout expiration latency, which will allow userspace to block for less than 1 tick. This will fix some well-known vmm(4)/vmd(8) time problems. We could also provide a very fast profiling tick for dt(4) on demand, and disable it when btrace(8) exits. There wouldn't be a need to run the profiling trace at the fixed hardclock(9) rate, hz(9). In general, parts of the kernel could benefit from having direct control of the clock interrupt. 2. An MI clock interrupt scheduler will allow us to reduce the clock interrupt rate or disable the clock interrupt entirely, saving power. For example, acpicpu(4) could temporarily stop the clock interrupt on very idle CPUs, allowing them to remain in low-power states for longer periods of time. In general, if there is no work to do, most CPUs in the system don't need to tick. 3. Parts of the MD clock interrupt code are very repetitive. We have 11 different hardclock/statclock dispatch loops. armv7 has 4 such loops. It would be pragmatic to consolidate these into a single dispatch loop and use it on every platform. Second, "how does it work?". The high level clockintr(9) life-cycle proceeds like this: 1. The primary CPU calls clockintr_init(9) to initialize global clockintr(9) state. Usually this is done from cpu_initclocks(). 2. The primary CPU calls clockintr_cpu_init(9) to initialize its local clockintr(9) state. Every CPU has a 'clockintr_queue' struct kept in its cpu_info struct. The struct contains a work schedule. During clockintr_cpu_init(9), an 'intrclock' struct may also be installed on the calling CPU. An intrclock provides a uniform interface to a CPU for manipulating its interrupt clock. If no intrclock is installed, the platform code is responsible for rearming the clock interrupt. Most platforms have a suitable hardware clock, though. 3. During cpu_hatch(), the secondary CPUs all initialize their local state with clockintr_cpu_init(9). 4. When a clock interrupt arrives, the CPU calls clockintr_dispatch(9) from the MD clock interrupt handler, e.g. lapic_clockintr(). clockintr_dispatch() runs hardclock(), statclock(), and schedclock(). It might run them more than once if the interrupt is late. It then rearms the installed intrclock to fire when the next event is scheduled to expire. 5. Repeat step 4 indefinitely until the system shuts down, suspends, or hibernates. 6. During resume, the primary CPU calls inittodr(9) to advance the system uptime clock across the duration the system was down. 7. Go to step 2. This time, clockintr_cpu_init(9) skips past any downtime on the caller's work schedule. This prevents a "thundering herd" of useless work during the first clock interrupt after the system resumes. There is a manpage in the patch with additional detail on what these interfaces do. -Scott Index: distrib/sets/lists/comp/mi === RCS file: /cvs/src/distrib/sets/lists/comp/mi,v retrieving revision 1.1610 diff -u -p -r1.1610 mi --- distrib/sets/lists/comp/mi 7 Oct 2022 15:43:41 - 1.1610 +++ distrib/sets/lists/comp/mi 28 Oct 2022 16:39:43 - @@ -1286,6 +1286,7 @@ ./usr/include/sys/cdefs.h ./usr/include/sys/cdio.h ./usr/include/sys/chio.h +./usr/include/sys/clockintr.h ./usr/include/sys/conf.h ./usr/include/sys/core.h ./usr/include/sys/ctf.h @@ -3071,6 +3072,7 @@ ./usr/share/man/man9/bufq_init.9 ./usr/share/man/man9/bus_dma.9 ./usr/share/man/man9/bus_space.9 +./usr/share/man/man9/clockintr.9 ./usr/share/man/man9/cond_init.9 ./usr/share/man/man9/config_attach.9 ./usr/share/man/man9/config_defer.9 Index: share/man/man9/Makefile === RCS file: /cvs/src/share/man/man9/Makefile,v retrieving revision 1.307 diff -u -p -r1.307 Mak
Fwd: Gmux Driver for MacBook Retina Display
Hi,
I'm resending this email in case adding this driver is useful for the
project.
If not useful, no problem. Will work on other issues that may arise in this
hardware.
Thanks,
Leonardo
-- Forwarded message -
De: leomoreno
Date: vie, 9 sept 2022 a las 11:43
Subject: Gmux Driver for MacBook Retina Display
To:
Hello,
I wrote this driver to control the backlight in my
MacBook Pro 2015 with Retina Display.
I had to refer to some of the code in the linux
apple-gmux.c driver to learn how to communicate
with the chip. This could cause some issue with the
license? That's why I haven't included any license
text in the file.
Also based this driver heavily on parts of asmc.c and abl.c
Built it today with current and it works correctly using
wsconsctl.
Does it stand any chance to get commited? After
any necessary corrections.
Thanks,
Leonardo
Index: sys/arch/amd64/conf/GENERIC
===
RCS file: /cvs/src/sys/arch/amd64/conf/GENERIC,v
retrieving revision 1.512
diff -u -p -u -p -r1.512 GENERIC
--- sys/arch/amd64/conf/GENERIC 8 Mar 2022 15:08:01 - 1.512
+++ sys/arch/amd64/conf/GENERIC 9 Sep 2022 16:30:21 -
@@ -82,6 +82,7 @@ tpm* at acpi?
acpihve* at acpi?
acpisurface* at acpi?
acpihid* at acpi?
+gmux* at acpi?# Apple MacBookPro Retina Backlight
ipmi0 at acpi? disable
ccpmic*at iic?
tipmic*at iic?
Index: sys/dev/acpi/files.acpi
===
RCS file: /cvs/src/sys/dev/acpi/files.acpi,v
retrieving revision 1.65
diff -u -p -u -p -r1.65 files.acpi
--- sys/dev/acpi/files.acpi 31 Aug 2022 16:10:59 - 1.65
+++ sys/dev/acpi/files.acpi 9 Sep 2022 16:30:22 -
@@ -90,6 +90,11 @@ device abl
attach abl at acpi
file dev/acpi/abl.c abl
+# Apple MacBookPro Retina Display Backlight
+device gmux
+attach gmux at acpi
+file dev/acpi/gmux.c gmux
+
# Apple System Management Controller (SMC)
device asmc
attach asmc at acpi
Index: sys/dev/acpi/gmux.c
===
RCS file: sys/dev/acpi/gmux.c
diff -N sys/dev/acpi/gmux.c
--- /dev/null 1 Jan 1970 00:00:00 -
+++ sys/dev/acpi/gmux.c 9 Sep 2022 16:30:22 -
@@ -0,0 +1,244 @@
+/*
+ * Driver to control backlight in MacBook Retina Display.
+ * Address numbers and inner workings heavily derived from
+ * apple-gmux Linux driver.
+ *
+ * */
+
+
+#include
+#include
+
+#include
+#include
+#include
+#include
+
+#include
+#include
+
+#ifdef GMUX_DEBUG
+#define DPRINTF(x) printf x
+#else
+#define DPRINTF(x)
+#endif
+
+#define GMUX_PORT_BRIGHTNESS 0x74
+#define GMUX_PORT_VALUE0xc2
+#define GMUX_PORT_READ 0xd0
+#define GMUX_PORT_WRITE0xd4
+
+#define GMUX_MIN_BRIGHTNESS0
+#define GMUX_MAX_BRIGHTNESS1023
+
+struct gmux_softc {
+ struct devicesc_dev;
+
+ struct acpi_softc *sc_acpi;
+ struct aml_node *sc_devnode;
+
+ bus_space_tag_t sc_iot;
+ bus_space_handle_t sc_ioh;
+
+ uint16_t sc_brightness;
+};
+
+intgmux_match(struct device *, void *, void *);
+void gmux_attach(struct device *, struct device *, void *);
+void gmux_complete(struct gmux_softc *);
+void gmux_ready(struct gmux_softc *);
+bool gmux_confirm_retina_display(struct gmux_softc *);
+intgmux_get_brightness(struct gmux_softc *);
+intgmux_set_brightness(struct gmux_softc *,uint16_t);
+
+/* Hooks for wsconsole brightness control. */
+intgmux_get_param(struct wsdisplay_param *);
+intgmux_set_param(struct wsdisplay_param *);
+
+const struct cfattach gmux_ca = {
+ sizeof(struct gmux_softc), gmux_match, gmux_attach, NULL, NULL
+};
+
+struct cfdriver gmux_cd = {
+ NULL, "gmux", DV_DULL
+};
+
+const char *gmux_hids[] = {
+ "APP000B", NULL
+};
+
+int
+gmux_match(struct device *parent, void *match, void *aux)
+{
+ struct acpi_attach_args *aa = aux;
+ struct cfdata *cf = match;
+
+ return acpi_matchhids(aa, gmux_hids, cf->cf_driver->cd_name);
+
+}
+
+void
+gmux_attach(struct device *parent, struct device *self, void *aux)
+{
+ struct gmux_softc *sc = (struct gmux_softc *)self;
+ struct acpi_attach_args *aaa = aux;
+ struct aml_value res;
+ int64_t sta;
+
+ sc->sc_acpi = (struct acpi_softc *)parent;
+ sc->sc_devnode = aaa->aaa_node;
+
+ printf(": %s", sc->sc_devnode->name);
+
+sta = acpi_getsta(sc->sc_acpi, sc->sc_devnode);
+ if ((sta & (STA_PRESENT | STA_ENABLED | STA_DEV_OK)) !=
+ (STA_PRESENT | STA_ENABLED | STA_DEV_OK)) {
+ printf(": not enabled\n");
+ return;
+ }
+
+ if (!(aml_evalname(sc->sc_acpi, sc->sc_devnode, "_CID", 0, NUL
Re: Towards unlocking mmap(2) & munmap(2)
On 20/10/22(Thu) 16:17, Martin Pieuchot wrote:
> On 11/09/22(Sun) 12:26, Martin Pieuchot wrote:
> > Diff below adds a minimalist set of assertions to ensure proper locks
> > are held in uvm_mapanon() and uvm_unmap_remove() which are the guts of
> > mmap(2) for anons and munmap(2).
> >
> > Please test it with WITNESS enabled and report back.
>
> New version of the diff that includes a lock/unlock dance in
> uvm_map_teardown(). While grabbing this lock should not be strictly
> necessary because no other reference to the map should exist when the
> reaper is holding it, it helps make progress with asserts. Grabbing
> the lock is easy and it can also save us a lot of time if there is any
> reference counting bugs (like we've discovered w/ vnode and swapping).
Here's an updated version that adds a lock/unlock dance in
uvm_map_deallocate() to satisfy the assert in uvm_unmap_remove().
Thanks to tb@ from pointing this out.
I received many positive feedback and test reports, I'm now asking for
oks.
Index: uvm/uvm_addr.c
===
RCS file: /cvs/src/sys/uvm/uvm_addr.c,v
retrieving revision 1.31
diff -u -p -r1.31 uvm_addr.c
--- uvm/uvm_addr.c 21 Feb 2022 10:26:20 - 1.31
+++ uvm/uvm_addr.c 28 Oct 2022 08:41:30 -
@@ -416,6 +416,8 @@ uvm_addr_invoke(struct vm_map *map, stru
!(hint >= uaddr->uaddr_minaddr && hint < uaddr->uaddr_maxaddr))
return ENOMEM;
+ vm_map_assert_anylock(map);
+
error = (*uaddr->uaddr_functions->uaddr_select)(map, uaddr,
entry_out, addr_out, sz, align, offset, prot, hint);
Index: uvm/uvm_fault.c
===
RCS file: /cvs/src/sys/uvm/uvm_fault.c,v
retrieving revision 1.132
diff -u -p -r1.132 uvm_fault.c
--- uvm/uvm_fault.c 31 Aug 2022 01:27:04 - 1.132
+++ uvm/uvm_fault.c 28 Oct 2022 08:41:30 -
@@ -1626,6 +1626,7 @@ uvm_fault_unwire_locked(vm_map_t map, va
struct vm_page *pg;
KASSERT((map->flags & VM_MAP_INTRSAFE) == 0);
+ vm_map_assert_anylock(map);
/*
* we assume that the area we are unwiring has actually been wired
Index: uvm/uvm_map.c
===
RCS file: /cvs/src/sys/uvm/uvm_map.c,v
retrieving revision 1.301
diff -u -p -r1.301 uvm_map.c
--- uvm/uvm_map.c 24 Oct 2022 15:11:56 - 1.301
+++ uvm/uvm_map.c 28 Oct 2022 08:46:28 -
@@ -491,6 +491,8 @@ uvmspace_dused(struct vm_map *map, vaddr
vaddr_t stack_begin, stack_end; /* Position of stack. */
KASSERT(map->flags & VM_MAP_ISVMSPACE);
+ vm_map_assert_anylock(map);
+
vm = (struct vmspace *)map;
stack_begin = MIN((vaddr_t)vm->vm_maxsaddr, (vaddr_t)vm->vm_minsaddr);
stack_end = MAX((vaddr_t)vm->vm_maxsaddr, (vaddr_t)vm->vm_minsaddr);
@@ -570,6 +572,8 @@ uvm_map_isavail(struct vm_map *map, stru
if (addr + sz < addr)
return 0;
+ vm_map_assert_anylock(map);
+
/*
* Kernel memory above uvm_maxkaddr is considered unavailable.
*/
@@ -1457,6 +1461,8 @@ uvm_map_mkentry(struct vm_map *map, stru
entry->guard = 0;
entry->fspace = 0;
+ vm_map_assert_wrlock(map);
+
/* Reset free space in first. */
free = uvm_map_uaddr_e(map, first);
uvm_mapent_free_remove(map, free, first);
@@ -1584,6 +1590,8 @@ boolean_t
uvm_map_lookup_entry(struct vm_map *map, vaddr_t address,
struct vm_map_entry **entry)
{
+ vm_map_assert_anylock(map);
+
*entry = uvm_map_entrybyaddr(&map->addr, address);
return *entry != NULL && !UVM_ET_ISHOLE(*entry) &&
(*entry)->start <= address && (*entry)->end > address;
@@ -1704,6 +1712,8 @@ uvm_map_is_stack_remappable(struct vm_ma
vaddr_t end = addr + sz;
struct vm_map_entry *first, *iter, *prev = NULL;
+ vm_map_assert_anylock(map);
+
if (!uvm_map_lookup_entry(map, addr, &first)) {
printf("map stack 0x%lx-0x%lx of map %p failed: no mapping\n",
addr, end, map);
@@ -1868,6 +1878,8 @@ uvm_mapent_mkfree(struct vm_map *map, st
vaddr_t addr; /* Start of freed range. */
vaddr_t end; /* End of freed range. */
+ UVM_MAP_REQ_WRITE(map);
+
prev = *prev_ptr;
if (prev == entry)
*prev_ptr = prev = NULL;
@@ -1996,10 +2008,7 @@ uvm_unmap_remove(struct vm_map *map, vad
if (start >= end)
return 0;
- if ((map->flags & VM_MAP_INTRSAFE) == 0)
- splassert(IPL_NONE);
- else
- splassert(IPL_VM);
+ vm_map_assert_wrlock(map);
/* Find first affected entry. */
entry = uvm_map_entrybyaddr(&map->addr, start);
@@ -2531,6 +2540,8 @@ uvm_map_teardown(struct vm_map *map)
KASSERT((map->flags & VM_MAP_IN
