[haiku-commits] r36373 - in haiku/trunk: headers/private/kernel/vm src/system/kernel/vm
- From: ingo_weinhold@xxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Tue, 20 Apr 2010 16:04:18 +0200 (CEST)
Author: bonefish
Date: 2010-04-20 16:04:18 +0200 (Tue, 20 Apr 2010)
New Revision: 36373
Changeset: http://dev.haiku-os.org/changeset/36373/haiku
Modified:
haiku/trunk/headers/private/kernel/vm/VMCache.h
haiku/trunk/src/system/kernel/vm/VMAnonymousCache.cpp
haiku/trunk/src/system/kernel/vm/VMAnonymousCache.h
haiku/trunk/src/system/kernel/vm/VMCache.cpp
Log:
Made VMCache::Resize() virtual and let VMAnonymousCache override it to free
swap space when the cache shrinks. Currently the implementation stil leaks
swap space of busy pages.
Modified: haiku/trunk/headers/private/kernel/vm/VMCache.h
===================================================================
--- haiku/trunk/headers/private/kernel/vm/VMCache.h 2010-04-20 13:56:45 UTC
(rev 36372)
+++ haiku/trunk/headers/private/kernel/vm/VMCache.h 2010-04-20 14:04:18 UTC
(rev 36373)
@@ -110,7 +110,7 @@
status_t WriteModified();
status_t
SetMinimalCommitment(off_t commitment,
int
priority);
- status_t Resize(off_t newSize,
int priority);
+ virtual status_t Resize(off_t newSize, int
priority);
status_t
FlushAndRemoveAllPages();
Modified: haiku/trunk/src/system/kernel/vm/VMAnonymousCache.cpp
===================================================================
--- haiku/trunk/src/system/kernel/vm/VMAnonymousCache.cpp 2010-04-20
13:56:45 UTC (rev 36372)
+++ haiku/trunk/src/system/kernel/vm/VMAnonymousCache.cpp 2010-04-20
14:04:18 UTC (rev 36373)
@@ -464,6 +464,65 @@
status_t
+VMAnonymousCache::Resize(off_t newSize, int priority)
+{
+ // If the cache size shrinks, drop all swap pages beyond the new size.
+ if (fAllocatedSwapSize > 0) {
+ page_num_t oldPageCount = (virtual_end + B_PAGE_SIZE - 1) >>
PAGE_SHIFT;
+ swap_block* swapBlock = NULL;
+
+ for (page_num_t pageIndex = (newSize + B_PAGE_SIZE - 1) >>
PAGE_SHIFT;
+ pageIndex < oldPageCount && fAllocatedSwapSize
> 0;
+ pageIndex++) {
+ WriteLocker locker(sSwapHashLock);
+
+ // Get the swap slot index for the page.
+ swap_addr_t blockIndex = pageIndex & SWAP_BLOCK_MASK;
+ if (swapBlock == NULL || blockIndex == 0) {
+ swap_hash_key key = { this, pageIndex };
+ swapBlock = sSwapHashTable.Lookup(key);
+
+ if (swapBlock == NULL) {
+ pageIndex = ROUNDUP(pageIndex + 1,
SWAP_BLOCK_PAGES);
+ continue;
+ }
+ }
+
+ swap_addr_t slotIndex =
swapBlock->swap_slots[blockIndex];
+ vm_page* page;
+ if (slotIndex != SWAP_SLOT_NONE
+ && ((page = LookupPage((off_t)pageIndex *
B_PAGE_SIZE)) == NULL
+ || !page->busy)) {
+ // TODO: We skip (i.e. leak) swap space
of busy pages, since
+ // there could be I/O going on (paging
in/out). Waiting is
+ // not an option as 1. unlocking the
cache means that new
+ // swap pages could be added in a range
we've already
+ // cleared (since the cache still has
the old size) and 2.
+ // we'd risk a deadlock in case we come
from the file cache
+ // and the FS holds the node's
write-lock. We should mark
+ // the page invalid and let the one
responsible clean up.
+ // There's just no such mechanism yet.
+ swap_slot_dealloc(slotIndex, 1);
+ fAllocatedSwapSize -= B_PAGE_SIZE;
+
+ swapBlock->swap_slots[blockIndex] =
SWAP_SLOT_NONE;
+ if (--swapBlock->used == 0) {
+ // All swap pages have been freed -- we
can discard the swap
+ // block.
+
sSwapHashTable.RemoveUnchecked(swapBlock);
+ object_cache_free(sSwapBlockCache,
swapBlock,
+ CACHE_DONT_WAIT_FOR_MEMORY
+ |
CACHE_DONT_LOCK_KERNEL_SPACE);
+ }
+ }
+ }
+ }
+
+ return VMCache::Resize(newSize, priority);
+}
+
+
+status_t
VMAnonymousCache::Commit(off_t size, int priority)
{
TRACE("%p->VMAnonymousCache::Commit(%lld)\n", this, size);
Modified: haiku/trunk/src/system/kernel/vm/VMAnonymousCache.h
===================================================================
--- haiku/trunk/src/system/kernel/vm/VMAnonymousCache.h 2010-04-20 13:56:45 UTC
(rev 36372)
+++ haiku/trunk/src/system/kernel/vm/VMAnonymousCache.h 2010-04-20 14:04:18 UTC
(rev 36373)
@@ -38,6 +38,8 @@
int32
numGuardPages,
uint32
allocationFlags);
+ virtual status_t Resize(off_t newSize, int
priority);
+
virtual status_t Commit(off_t size, int
priority);
virtual bool HasPage(off_t offset);
virtual bool DebugHasPage(off_t offset);
Modified: haiku/trunk/src/system/kernel/vm/VMCache.cpp
===================================================================
--- haiku/trunk/src/system/kernel/vm/VMCache.cpp 2010-04-20 13:56:45 UTC
(rev 36372)
+++ haiku/trunk/src/system/kernel/vm/VMCache.cpp 2010-04-20 14:04:18 UTC
(rev 36373)
@@ -1038,8 +1038,6 @@
status_t
VMCache::Resize(off_t newSize, int priority)
{
-// TODO: This method must be virtual as VMAnonymousCache needs to free
allocated
-// swap pages!
TRACE(("VMCache::Resize(cache %p, newSize %Ld) old size %Ld\n",
this, newSize, this->virtual_end));
this->AssertLocked();
Other related posts:
- » [haiku-commits] r36373 - in haiku/trunk: headers/private/kernel/vm src/system/kernel/vm - ingo_weinhold
