[haiku-commits] r35299 - haiku/trunk/src/system/kernel/cache
- From: ingo_weinhold@xxxxxx
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Tue, 26 Jan 2010 18:22:46 +0100 (CET)
Author: bonefish
Date: 2010-01-26 18:22:46 +0100 (Tue, 26 Jan 2010)
New Revision: 35299
Changeset: http://dev.haiku-os.org/changeset/35299/haiku
Ticket: http://dev.haiku-os.org/ticket/3768
Modified:
haiku/trunk/src/system/kernel/cache/file_cache.cpp
Log:
cache_io(): Reevaluate the memory situation periodically. Deciding at the
beginning whether to pass the cache by really doesn't help when
reading/writing a huge amount of data, since a low memory situation is likely
to occur at some point during the operation. This should fix the main issue
of #3768.
Modified: haiku/trunk/src/system/kernel/cache/file_cache.cpp
===================================================================
--- haiku/trunk/src/system/kernel/cache/file_cache.cpp 2010-01-26 17:09:15 UTC
(rev 35298)
+++ haiku/trunk/src/system/kernel/cache/file_cache.cpp 2010-01-26 17:22:46 UTC
(rev 35299)
@@ -736,25 +736,6 @@
if (size == 0)
return B_OK;
- cache_func function;
- if (doWrite) {
- // in low memory situations, we bypass the cache beyond a
- // certain I/O size
- if (size >= BYPASS_IO_SIZE
- && low_resource_state(B_KERNEL_RESOURCE_PAGES)
- != B_NO_LOW_RESOURCE) {
- function = write_to_file;
- } else
- function = write_to_cache;
- } else {
- if (size >= BYPASS_IO_SIZE
- && low_resource_state(B_KERNEL_RESOURCE_PAGES)
- != B_NO_LOW_RESOURCE) {
- function = read_from_file;
- } else
- function = read_into_cache;
- }
-
// "offset" and "lastOffset" are always aligned to B_PAGE_SIZE,
// the "last*" variables always point to the end of the last
// satisfied request part
@@ -767,18 +748,33 @@
size_t lastReservedPages = min_c(MAX_IO_VECS, (pageOffset + bytesLeft
+ B_PAGE_SIZE - 1) >> PAGE_SHIFT);
size_t reservePages = 0;
+ size_t pagesProcessed = 0;
+ cache_func function = NULL;
reserve_pages(ref, lastReservedPages, doWrite);
AutoLocker<VMCache> locker(cache);
while (bytesLeft > 0) {
+ // Periodically reevaluate the low memory situation and select
the
+ // read/write hook accordingly
+ if (pagesProcessed % 32 == 0) {
+ if (size >= BYPASS_IO_SIZE
+ && low_resource_state(B_KERNEL_RESOURCE_PAGES)
+ != B_NO_LOW_RESOURCE) {
+ // In low memory situations we bypass the cache
beyond a
+ // certain I/O size.
+ function = doWrite ? write_to_file :
read_from_file;
+ } else
+ function = doWrite ? write_to_cache :
read_into_cache;
+ }
+
// check if this page is already in memory
vm_page* page = cache->LookupPage(offset);
if (page != NULL) {
// The page may be busy - since we need to unlock the
cache sometime
// in the near future, we need to satisfy the request
of the pages
// we didn't get yet (to make sure no one else
interferes in the
- // mean time).
+ // meantime).
status_t status = satisfy_cache_io(ref, cookie,
function, offset,
buffer, useBuffer, pageOffset, bytesLeft,
reservePages,
lastOffset, lastBuffer, lastPageOffset,
lastLeft,
@@ -863,6 +859,7 @@
bytesLeft -= bytesInPage;
pageOffset = 0;
offset += B_PAGE_SIZE;
+ pagesProcessed++;
if (buffer - lastBuffer + lastPageOffset >= kMaxChunkSize) {
status_t status = satisfy_cache_io(ref, cookie,
function, offset,
Other related posts:
- » [haiku-commits] r35299 - haiku/trunk/src/system/kernel/cache - ingo_weinhold
