[haiku-commits] haiku: hrev48145 - src/system/kernel/vm headers/private/kernel/vm
- From: ingo_weinhold@xxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Wed, 29 Oct 2014 12:37:33 +0100 (CET)
hrev48145 adds 2 changesets to branch 'master'
old head: cf3c703b7ac57f097ae92a6173747f1dc2864941
new head: 7ca277b9caaec8e873309354e3c7fe8453c34b64
overview: http://cgit.haiku-os.org/haiku/log/?qt=range&q=7ca277b+%5Ecf3c703
----------------------------------------------------------------------------
078a965: vm_soft_fault(): Avoid deadlock waiting for wired ranges
* VMArea::AddWaiterIfWired(): Replace the ignoreRange argument by a
flags argument and introduce (currently only) flag
IGNORE_WRITE_WIRED_RANGES. If specified, ranges wired for writing
are ignored. Ignoring just a single specified range doesn't cut it
in vm_soft_fault(), and there aren't any other users of that feature.
* vm_soft_fault(): When having to unmap a page of a lower cache, this
page cannot be wired for writing. So we can safely ignore all
writed-wired ranges, instead of just our own. We even have to do that
in case there's another thread that concurrently tries to write-wire
the same page, since otherwise we'd deadlock waiting for each other.
7ca277b: vm_soft_fault(): remove unused wiredRange parameter
[ Ingo Weinhold <ingo_weinhold@xxxxxx> ]
----------------------------------------------------------------------------
3 files changed, 26 insertions(+), 18 deletions(-)
headers/private/kernel/vm/VMArea.h | 11 +++++++++--
src/system/kernel/vm/VMArea.cpp | 13 +++++++------
src/system/kernel/vm/vm.cpp | 20 ++++++++++----------
############################################################################
Commit: 078a965f65b5f56ecb3f0c72fc97a36238509ca8
URL: http://cgit.haiku-os.org/haiku/commit/?id=078a965
Author: Ingo Weinhold <ingo_weinhold@xxxxxx>
Date: Wed Oct 29 11:32:37 2014 UTC
vm_soft_fault(): Avoid deadlock waiting for wired ranges
* VMArea::AddWaiterIfWired(): Replace the ignoreRange argument by a
flags argument and introduce (currently only) flag
IGNORE_WRITE_WIRED_RANGES. If specified, ranges wired for writing
are ignored. Ignoring just a single specified range doesn't cut it
in vm_soft_fault(), and there aren't any other users of that feature.
* vm_soft_fault(): When having to unmap a page of a lower cache, this
page cannot be wired for writing. So we can safely ignore all
writed-wired ranges, instead of just our own. We even have to do that
in case there's another thread that concurrently tries to write-wire
the same page, since otherwise we'd deadlock waiting for each other.
----------------------------------------------------------------------------
diff --git a/headers/private/kernel/vm/VMArea.h
b/headers/private/kernel/vm/VMArea.h
index 669c98a..7c4621c 100644
--- a/headers/private/kernel/vm/VMArea.h
+++ b/headers/private/kernel/vm/VMArea.h
@@ -89,6 +89,14 @@ struct VMPageWiringInfo {
struct VMArea {
+public:
+ enum {
+ // AddWaiterIfWired() flags
+ IGNORE_WRITE_WIRED_RANGES = 0x01, // ignore existing
ranges that
+
// wire for writing
+ };
+
+public:
char* name;
area_id id;
uint32 protection;
@@ -130,8 +138,7 @@ public:
bool
AddWaiterIfWired(VMAreaUnwiredWaiter* waiter);
bool
AddWaiterIfWired(VMAreaUnwiredWaiter* waiter,
- addr_t
base, size_t size,
-
VMAreaWiredRange* ignoreRange = NULL);
+ addr_t
base, size_t size, uint32 flags = 0);
protected:
VMArea(VMAddressSpace* addressSpace,
diff --git a/src/system/kernel/vm/VMArea.cpp b/src/system/kernel/vm/VMArea.cpp
index b87b1d6..ffe111e 100644
--- a/src/system/kernel/vm/VMArea.cpp
+++ b/src/system/kernel/vm/VMArea.cpp
@@ -185,19 +185,20 @@ VMArea::AddWaiterIfWired(VMAreaUnwiredWaiter* waiter)
that intersects with the given address range.
\param base The base of the address range to check.
\param size The size of the address range to check.
- \param ignoreRange If given, this wired range of the area is not checked
- whether it intersects with the given address range. Useful when
the
- caller has added the range and only wants to check intersection
with
- other ranges.
+ \param flags
+ - \c IGNORE_WRITE_WIRED_RANGES: Ignore ranges wired for writing.
\return \c true, if the waiter has been added, \c false otherwise.
*/
bool
VMArea::AddWaiterIfWired(VMAreaUnwiredWaiter* waiter, addr_t base, size_t size,
- VMAreaWiredRange* ignoreRange)
+ uint32 flags)
{
for (VMAreaWiredRangeList::Iterator it = fWiredRanges.GetIterator();
VMAreaWiredRange* range = it.Next();) {
- if (range != ignoreRange && range->IntersectsWith(base, size)) {
+ if ((flags & IGNORE_WRITE_WIRED_RANGES) != 0 && range->writable)
+ continue;
+
+ if (range->IntersectsWith(base, size)) {
waiter->area = this;
waiter->base = base;
waiter->size = size;
diff --git a/src/system/kernel/vm/vm.cpp b/src/system/kernel/vm/vm.cpp
index 4c65cae..5253a58 100644
--- a/src/system/kernel/vm/vm.cpp
+++ b/src/system/kernel/vm/vm.cpp
@@ -4681,10 +4681,14 @@ vm_soft_fault(VMAddressSpace* addressSpace, addr_t
originalAddress,
if (unmapPage) {
// If the page is wired, we can't unmap it. Wait until
it is unwired
- // again and restart.
+ // again and restart. Note that the page cannot be
wired for
+ // writing, since it it isn't in the topmost cache. So
we can safely
+ // ignore ranges wired for writing (our own and other
concurrent
+ // wiring attempts in progress) and in fact have to do
that to avoid
+ // a deadlock.
VMAreaUnwiredWaiter waiter;
if (area->AddWaiterIfWired(&waiter, address,
B_PAGE_SIZE,
- wiredRange)) {
+ VMArea::IGNORE_WRITE_WIRED_RANGES)) {
// unlock everything and wait
if (context.pageAllocated) {
// ... but since we allocated a page
and inserted it into
############################################################################
Revision: hrev48145
Commit: 7ca277b9caaec8e873309354e3c7fe8453c34b64
URL: http://cgit.haiku-os.org/haiku/commit/?id=7ca277b
Author: Ingo Weinhold <ingo_weinhold@xxxxxx>
Date: Wed Oct 29 11:36:46 2014 UTC
vm_soft_fault(): remove unused wiredRange parameter
----------------------------------------------------------------------------
diff --git a/src/system/kernel/vm/vm.cpp b/src/system/kernel/vm/vm.cpp
index 5253a58..53875e4 100644
--- a/src/system/kernel/vm/vm.cpp
+++ b/src/system/kernel/vm/vm.cpp
@@ -268,8 +268,7 @@ static cache_info* sCacheInfoTable;
static void delete_area(VMAddressSpace* addressSpace, VMArea* area,
bool addressSpaceCleanup);
static status_t vm_soft_fault(VMAddressSpace* addressSpace, addr_t address,
- bool isWrite, bool isExecute, bool isUser, vm_page** wirePage,
- VMAreaWiredRange* wiredRange = NULL);
+ bool isWrite, bool isExecute, bool isUser, vm_page** wirePage);
static status_t map_backing_store(VMAddressSpace* addressSpace,
VMCache* cache, off_t offset, const char* areaName, addr_t size, int
wiring,
int protection, int mapping, uint32 flags,
@@ -4529,14 +4528,11 @@ fault_get_page(PageFaultContext& context)
\param wirePage On success, if non \c NULL, the wired count of the page
mapped at the given address is incremented and the page is
returned
via this parameter.
- \param wiredRange If given, this wiredRange is ignored when checking
whether
- an already mapped page at the virtual address can be unmapped.
\return \c B_OK on success, another error code otherwise.
*/
static status_t
vm_soft_fault(VMAddressSpace* addressSpace, addr_t originalAddress,
- bool isWrite, bool isExecute, bool isUser, vm_page** wirePage,
- VMAreaWiredRange* wiredRange)
+ bool isWrite, bool isExecute, bool isUser, vm_page** wirePage)
{
FTRACE(("vm_soft_fault: thid 0x%" B_PRIx32 " address 0x%" B_PRIxADDR ",
"
"isWrite %d, isUser %d\n", thread_get_current_thread_id(),
@@ -5415,7 +5411,7 @@ vm_wire_page(team_id team, addr_t address, bool writable,
addressSpaceLocker.Unlock();
error = vm_soft_fault(addressSpace, pageAddress, writable,
false,
- isUser, &page, &info->range);
+ isUser, &page);
if (error != B_OK) {
// The page could not be mapped -- clean up.
@@ -5595,7 +5591,7 @@ lock_memory_etc(team_id team, void* address, size_t
numBytes, uint32 flags)
addressSpaceLocker.Unlock();
error = vm_soft_fault(addressSpace,
nextAddress, writable,
- false, isUser, &page, range);
+ false, isUser, &page);
addressSpaceLocker.Lock();
cacheChainLocker.SetTo(vm_area_get_locked_cache(area));
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