/*
- * $Id$
- *
* DEBUG: section 20 Storage Manager Swapout Functions
* AUTHOR: Duane Wessels
*
#include "squid.h"
#include "cbdata.h"
-#include "StoreClient.h"
+#include "globals.h"
#include "Store.h"
+#include "StoreClient.h"
/* FIXME: Abstract the use of this more */
#include "mem_node.h"
#include "MemObject.h"
-#include "SwapDir.h"
+#include "SquidConfig.h"
+#include "StatCounters.h"
+#include "store_log.h"
#include "swap_log_op.h"
+#include "SwapDir.h"
static void storeSwapOutStart(StoreEntry * e);
static StoreIOState::STIOCB storeSwapOutFileClosed;
} while (true);
}
-
/* This routine is called every time data is sent to the client side.
* It's overhead is therefor, significant.
*/
if (!mem_obj)
return;
- if (!swapoutPossible())
+ // this flag may change so we must check even if we are swappingOut
+ if (EBIT_TEST(flags, ENTRY_ABORTED)) {
+ assert(EBIT_TEST(flags, RELEASE_REQUEST));
+ // StoreEntry::abort() already closed the swap out file, if any
+ // no trimming: data producer must stop production if ENTRY_ABORTED
return;
+ }
+
+ const bool weAreOrMayBeSwappingOut = swappingOut() || mayStartSwapOut();
+
+ Store::Root().maybeTrimMemory(*this, weAreOrMayBeSwappingOut);
+
+ if (mem_obj->swapout.decision != MemObject::SwapOut::swPossible)
+ return; // nothing else to do
// Aborted entries have STORE_OK, but swapoutPossible rejects them. Thus,
// store_status == STORE_OK below means we got everything we wanted.
if (mem_obj->swapout.sio != NULL)
debugs(20, 7, "storeSwapOut: storeOffset() = " << mem_obj->swapout.sio->offset() );
- // buffered bytes we have not swapped out yet
- int64_t swapout_maxsize = mem_obj->endOffset() - mem_obj->swapout.queue_offset;
-
- assert(swapout_maxsize >= 0);
-
int64_t const lowest_offset = mem_obj->lowestMemReaderOffset();
debugs(20, 7, HERE << "storeSwapOut: lowest_offset = " << lowest_offset);
- // Check to see whether we're going to defer the swapout based upon size
- if (store_status != STORE_OK) {
- const int64_t expectedSize = mem_obj->expectedReplySize();
- const int64_t maxKnownSize = expectedSize < 0 ?
- swapout_maxsize : expectedSize;
- debugs(20, 7, HERE << "storeSwapOut: maxKnownSize= " << maxKnownSize);
-
- if (maxKnownSize < store_maxobjsize) {
- /*
- * NOTE: the store_maxobjsize here is the max of optional
- * max-size values from 'cache_dir' lines. It is not the
- * same as 'maximum_object_size'. By default, store_maxobjsize
- * will be set to -1. However, I am worried that this
- * deferance may consume a lot of memory in some cases.
- * Should we add an option to limit this memory consumption?
- */
- debugs(20, 5, "storeSwapOut: Deferring swapout start for " <<
- (store_maxobjsize - maxKnownSize) << " bytes");
- return;
- }
- }
-
-// TODO: it is better to trim as soon as we swap something out, not before
- trimMemory();
#if SIZEOF_OFF_T <= 4
if (mem_obj->endOffset() > 0x7FFF0000) {
- debugs(20, 0, "WARNING: preventing off_t overflow for " << url());
+ debugs(20, DBG_CRITICAL, "WARNING: preventing off_t overflow for " << url());
abort();
return;
}
if (swap_status == SWAPOUT_WRITING)
assert(mem_obj->inmem_lo <= mem_obj->objectBytesOnDisk() );
- if (!swapOutAble())
- return;
-
+ // buffered bytes we have not swapped out yet
+ const int64_t swapout_maxsize = mem_obj->availableForSwapOut();
+ assert(swapout_maxsize >= 0);
debugs(20, 7, "storeSwapOut: swapout_size = " << swapout_maxsize);
if (swapout_maxsize == 0) { // swapped everything we got
std::uppercase << e->swap_filen);
debugs(20, 5, HERE << "swap_file_sz = " <<
e->objectLen() << " + " << mem->swap_hdr_sz);
- assert(e->objectLen() >= 0); // we checked that above
+
e->swap_file_sz = e->objectLen() + mem->swap_hdr_sz;
e->swap_status = SWAPOUT_DONE;
- e->store()->updateSize(e->swap_file_sz, 1);
+ e->store()->swappedOut(*e);
// XXX: For some Stores, it is pointless to re-check cachability here
// and it leads to double counts in store_check_cachable_hist. We need
storeDirSwapLog(e, SWAP_LOG_ADD);
}
- statCounter.swap.outs++;
+ ++statCounter.swap.outs;
}
debugs(20, 3, "storeSwapOutFileClosed: " << __FILE__ << ":" << __LINE__);
e->unlock();
}
-/*
- * Is this entry a candidate for writing to disk?
- */
bool
-StoreEntry::swapOutAble() const
+StoreEntry::mayStartSwapOut()
{
- dlink_node *node;
+ // must be checked in the caller
+ assert(!EBIT_TEST(flags, ENTRY_ABORTED));
+ assert(!swappingOut());
- if (mem_obj->swapout.sio != NULL)
+ if (!Config.cacheSwap.n_configured)
+ return false;
+
+ assert(mem_obj);
+ MemObject::SwapOut::Decision &decision = mem_obj->swapout.decision;
+
+ // if we decided that swapout is not possible, do not repeat same checks
+ if (decision == MemObject::SwapOut::swImpossible) {
+ debugs(20, 3, HERE << " already rejected");
+ return false;
+ }
+
+ // if we decided that swapout is possible, do not repeat same checks
+ if (decision == MemObject::SwapOut::swPossible) {
+ debugs(20, 3, HERE << "already allowed");
return true;
+ }
- if (mem_obj->inmem_lo > 0)
+ // if we swapped out already, do not start over
+ if (swap_status == SWAPOUT_DONE) {
+ debugs(20, 3, HERE << "already did");
+ decision = MemObject::SwapOut::swImpossible;
return false;
+ }
- /*
- * If there are DISK clients, we must write to disk
- * even if its not cachable
- * RBC: Surely we should not create disk client on non cacheable objects?
- * therefore this should be an assert?
- * RBC 20030708: We can use disk to avoid mem races, so this shouldn't be
- * an assert.
- */
- for (node = mem_obj->clients.head; node; node = node->next) {
- if (((store_client *) node->data)->getType() == STORE_DISK_CLIENT)
- return true;
+ if (!checkCachable()) {
+ debugs(20, 3, HERE << "not cachable");
+ decision = MemObject::SwapOut::swImpossible;
+ return false;
}
- /* Don't pollute the disk with icons and other special entries */
- if (EBIT_TEST(flags, ENTRY_SPECIAL))
+ if (EBIT_TEST(flags, ENTRY_SPECIAL)) {
+ debugs(20, 3, HERE << url() << " SPECIAL");
+ decision = MemObject::SwapOut::swImpossible;
return false;
+ }
- if (!EBIT_TEST(flags, ENTRY_CACHABLE))
+ if (mem_obj->inmem_lo > 0) {
+ debugs(20, 3, "storeSwapOut: (inmem_lo > 0) imem_lo:" << mem_obj->inmem_lo);
+ decision = MemObject::SwapOut::swImpossible;
return false;
+ }
- if (!mem_obj->isContiguous())
+ if (!mem_obj->isContiguous()) {
+ debugs(20, 3, "storeSwapOut: not Contiguous");
+ decision = MemObject::SwapOut::swImpossible;
return false;
+ }
+
+ // check cache_dir max-size limit if all cache_dirs have it
+ if (store_maxobjsize >= 0) {
+ // TODO: add estimated store metadata size to be conservative
+
+ // use guaranteed maximum if it is known
+ const int64_t expectedEnd = mem_obj->expectedReplySize();
+ debugs(20, 7, HERE << "expectedEnd = " << expectedEnd);
+ if (expectedEnd > store_maxobjsize) {
+ debugs(20, 3, HERE << "will not fit: " << expectedEnd <<
+ " > " << store_maxobjsize);
+ decision = MemObject::SwapOut::swImpossible;
+ return false; // known to outgrow the limit eventually
+ }
+
+ // use current minimum (always known)
+ const int64_t currentEnd = mem_obj->endOffset();
+ if (currentEnd > store_maxobjsize) {
+ debugs(20, 3, HERE << "does not fit: " << currentEnd <<
+ " > " << store_maxobjsize);
+ decision = MemObject::SwapOut::swImpossible;
+ return false; // already does not fit and may only get bigger
+ }
+
+ // prevent final default swPossible answer for yet unknown length
+ if (expectedEnd < 0 && store_status != STORE_OK) {
+ const int64_t maxKnownSize = mem_obj->availableForSwapOut();
+ debugs(20, 7, HERE << "maxKnownSize= " << maxKnownSize);
+ /*
+ * NOTE: the store_maxobjsize here is the global maximum
+ * size of object cacheable in any of Squid cache stores
+ * both disk and memory stores.
+ *
+ * However, I am worried that this
+ * deferance may consume a lot of memory in some cases.
+ * Should we add an option to limit this memory consumption?
+ */
+ debugs(20, 5, HERE << "Deferring swapout start for " <<
+ (store_maxobjsize - maxKnownSize) << " bytes");
+ return true; // may still fit, but no final decision yet
+ }
+ }
+ decision = MemObject::SwapOut::swPossible;
return true;
}
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