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* Added a TODO about a problematic use of vm_page_allocate_page() in combination 

with vm_cache_acquire_locked_page_cache().
* Added new function vm_page_num_unused_pages() which returns the pages that are
  actually completely free and unused.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30514 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2009-04-30 15:46:55 +00:00
parent 1ce7a6b540
commit 2d8073a9dc
3 changed files with 15 additions and 2 deletions
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3
headers/private/kernel/vm_page.h
View File

@ -1,5 +1,5 @@
/*
* Copyright 2002-2008, Axel Dörfler, axeld@pinc-software.de.
* Copyright 2002-2009, Axel Dörfler, axeld@pinc-software.de.
* Distributed under the terms of the MIT License.
*
* Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
@ -35,6 +35,7 @@ void vm_page_requeue(struct vm_page *page, bool tail);
size_t vm_page_num_pages(void);
size_t vm_page_num_free_pages(void);
size_t vm_page_num_available_pages(void);
size_t vm_page_num_unused_pages(void);
void vm_page_get_stats(system_info *info);
status_t vm_page_write_modified_page_range(struct VMCache *cache,

3
src/system/kernel/vm/vm_cache.cpp
View File

@ -345,6 +345,9 @@ vm_cache_acquire_locked_page_cache(vm_page* page, bool dontWait)
return NULL;
}
// TODO: this is problematic, as it requires the caller not to have
// a lock on this cache (it might be called via
// vm_page_allocate_page(..., false)).
if (!cache->SwitchLock(&sCacheListLock)) {
// cache has been deleted
mutex_lock(&sCacheListLock);

11
src/system/kernel/vm/vm_page.cpp
View File

@ -1893,6 +1893,8 @@ vm_page_try_reserve_pages(uint32 count)
}
// TODO: you must not have locked a cache when calling this function with
// reserved == false. See vm_cache_acquire_locked_page_cache().
vm_page *
vm_page_allocate_page(int pageState, bool reserved)
{
@ -2167,13 +2169,20 @@ vm_page_num_free_pages(void)
{
size_t reservedPages = sReservedPages;
size_t count = free_page_queue_count() + sInactivePageQueue.count;
if (reservedPages > count)
if (reservedPages >= count)
return 0;
return count - reservedPages;
}
size_t
vm_page_num_unused_pages(void)
{
return free_page_queue_count() - sReservedPages;
}
void
vm_page_get_stats(system_info *info)
{