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* PageWriterRun::Go(), vm_page_write_modified_page_range(): When writing the

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page failed since the cache has been shrunk, we need not only remove the
  page from the cache, we also need to remove all of its area mappings and
  free it. Not removing the area mappings might have been the cause of #3110,
  not freeing it would cause it to be leaked for good.
* vm_page_write_modified_page_range(): When writing failed for another reason
  and the page wasn't in the modified queue before, we would lose the info
  in which queue it was before and setting the page state to modified would
  assume the active queue. This could potentially screw up our page queue
  structures.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@29992 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Ingo Weinhold
2009-04-07 14:06:07 +00:00
parent b3660edb89
commit 8c91d29b34
1 changed files with 33 additions and 13 deletions
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src/system/kernel/vm/vm_page.cpp
+33 -13
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@@ -1116,17 +1116,20 @@ PageWriterRun::Go()
move_page_to_active_or_inactive_queue(page, true);
page->busy_writing = false;
} else {
// We don't have to put the PAGE_MODIFIED bit back, as it's
// still in the modified pages list.
// Writing failed, so move the page back to the modified queue.
{
InterruptsSpinLocker locker(sPageLock);
page->state = PAGE_STATE_MODIFIED;
enqueue_page(&sModifiedPageQueue, page);
}
if (!page->busy_writing) {
// someone has cleared the busy_writing flag which tells
// us our page has gone invalid
// Someone has cleared the busy_writing flag which tells
// us our page has gone invalid. We need to remove it from the
// cache and free it completely.
vm_remove_all_page_mappings(page, NULL);
cache->RemovePage(page);
vm_page_free(cache, page);
} else
page->busy_writing = false;
}
@@ -1519,6 +1522,7 @@ vm_page_write_modified_page_range(struct VMCache *cache, uint32 firstPage,
continue;
}
int oldPageState = page->state;
page->state = PAGE_STATE_BUSY;
page->busy_writing = true;
@@ -1542,6 +1546,14 @@ vm_page_write_modified_page_range(struct VMCache *cache, uint32 firstPage,
status_t status = write_page(page, 0, NULL);
cache->Lock();
// Before disabling interrupts handle part of the special case that
// writing the page failed due the cache having been shrunk. We need to
// remove the page from the cache and free it.
if (status != B_OK && !page->busy_writing) {
vm_remove_all_page_mappings(page, NULL);
cache->RemovePage(page);
}
InterruptsSpinLocker locker(&sPageLock);
if (status == B_OK) {
@@ -1549,23 +1561,31 @@ vm_page_write_modified_page_range(struct VMCache *cache, uint32 firstPage,
move_page_to_active_or_inactive_queue(page, dequeuedPage);
page->busy_writing = false;
} else {
// We don't have to put the PAGE_MODIFIED bit back, as it's still
// in the modified pages list.
// Writing the page failed -- move to the modified queue. If we
// dequeued it from there, just enqueue it again, otherwise set the
// page set explicitly, which will take care of moving between the
// queues.
if (dequeuedPage) {
page->state = PAGE_STATE_MODIFIED;
enqueue_page(&sModifiedPageQueue, page);
} else {
page->state = oldPageState;
set_page_state_nolock(page, PAGE_STATE_MODIFIED);
}
if (!page->busy_writing) {
// someone has cleared the busy_writing flag which tells
// us our page has gone invalid
cache->RemovePage(page);
} else {
if (!dequeuedPage)
set_page_state_nolock(page, PAGE_STATE_MODIFIED);
// The busy_writing flag was cleared. That means the cache has
// been shrunk while we were trying to write the page and we
// have to free it now.
// Adjust temporary modified pages count, if necessary.
if (dequeuedPage && cache->temporary)
sModifiedTemporaryPages--;
// free the page
set_page_state_nolock(page, PAGE_STATE_FREE);
} else
page->busy_writing = false;
}
}
busyCondition.Unpublish();