1 files changed, 0 insertions, 187 deletions
diff --git a/contrib/qemu/block/qed-l2-cache.c b/contrib/qemu/block/qed-l2-cache.c
deleted file mode 100644
index e9b2aae44d9..00000000000
--- a/contrib/qemu/block/qed-l2-cache.c
+++ /dev/null
@@ -1,187 +0,0 @@
-/*
- * QEMU Enhanced Disk Format L2 Cache
- *
- * Copyright IBM, Corp. 2010
- *
- * Authors:
- *  Anthony Liguori   <aliguori@us.ibm.com>
- *
- * This work is licensed under the terms of the GNU LGPL, version 2 or later.
- * See the COPYING.LIB file in the top-level directory.
- *
- */
-
-/*
- * L2 table cache usage is as follows:
- *
- * An open image has one L2 table cache that is used to avoid accessing the
- * image file for recently referenced L2 tables.
- *
- * Cluster offset lookup translates the logical offset within the block device
- * to a cluster offset within the image file.  This is done by indexing into
- * the L1 and L2 tables which store cluster offsets.  It is here where the L2
- * table cache serves up recently referenced L2 tables.
- *
- * If there is a cache miss, that L2 table is read from the image file and
- * committed to the cache.  Subsequent accesses to that L2 table will be served
- * from the cache until the table is evicted from the cache.
- *
- * L2 tables are also committed to the cache when new L2 tables are allocated
- * in the image file.  Since the L2 table cache is write-through, the new L2
- * table is first written out to the image file and then committed to the
- * cache.
- *
- * Multiple I/O requests may be using an L2 table cache entry at any given
- * time.  That means an entry may be in use across several requests and
- * reference counting is needed to free the entry at the correct time.  In
- * particular, an entry evicted from the cache will only be freed once all
- * references are dropped.
- *
- * An in-flight I/O request will hold a reference to a L2 table cache entry for
- * the period during which it needs to access the L2 table.  This includes
- * cluster offset lookup, L2 table allocation, and L2 table update when a new
- * data cluster has been allocated.
- *
- * An interesting case occurs when two requests need to access an L2 table that
- * is not in the cache.  Since the operation to read the table from the image
- * file takes some time to complete, both requests may see a cache miss and
- * start reading the L2 table from the image file.  The first to finish will
- * commit its L2 table into the cache.  When the second tries to commit its
- * table will be deleted in favor of the existing cache entry.
- */
-
-#include "trace.h"
-#include "qed.h"
-
-/* Each L2 holds 2GB so this let's us fully cache a 100GB disk */
-#define MAX_L2_CACHE_SIZE 50
-
-/**
- * Initialize the L2 cache
- */
-void qed_init_l2_cache(L2TableCache *l2_cache)
-{
-    QTAILQ_INIT(&l2_cache->entries);
-    l2_cache->n_entries = 0;
-}
-
-/**
- * Free the L2 cache
- */
-void qed_free_l2_cache(L2TableCache *l2_cache)
-{
-    CachedL2Table *entry, *next_entry;
-
-    QTAILQ_FOREACH_SAFE(entry, &l2_cache->entries, node, next_entry) {
-        qemu_vfree(entry->table);
-        g_free(entry);
-    }
-}
-
-/**
- * Allocate an uninitialized entry from the cache
- *
- * The returned entry has a reference count of 1 and is owned by the caller.
- * The caller must allocate the actual table field for this entry and it must
- * be freeable using qemu_vfree().
- */
-CachedL2Table *qed_alloc_l2_cache_entry(L2TableCache *l2_cache)
-{
-    CachedL2Table *entry;
-
-    entry = g_malloc0(sizeof(*entry));
-    entry->ref++;
-
-    trace_qed_alloc_l2_cache_entry(l2_cache, entry);
-
-    return entry;
-}
-
-/**
- * Decrease an entry's reference count and free if necessary when the reference
- * count drops to zero.
- */
-void qed_unref_l2_cache_entry(CachedL2Table *entry)
-{
-    if (!entry) {
-        return;
-    }
-
-    entry->ref--;
-    trace_qed_unref_l2_cache_entry(entry, entry->ref);
-    if (entry->ref == 0) {
-        qemu_vfree(entry->table);
-        g_free(entry);
-    }
-}
-
-/**
- * Find an entry in the L2 cache.  This may return NULL and it's up to the
- * caller to satisfy the cache miss.
- *
- * For a cached entry, this function increases the reference count and returns
- * the entry.
- */
-CachedL2Table *qed_find_l2_cache_entry(L2TableCache *l2_cache, uint64_t offset)
-{
-    CachedL2Table *entry;
-
-    QTAILQ_FOREACH(entry, &l2_cache->entries, node) {
-        if (entry->offset == offset) {
-            trace_qed_find_l2_cache_entry(l2_cache, entry, offset, entry->ref);
-            entry->ref++;
-            return entry;
-        }
-    }
-    return NULL;
-}
-
-/**
- * Commit an L2 cache entry into the cache.  This is meant to be used as part of
- * the process to satisfy a cache miss.  A caller would allocate an entry which
- * is not actually in the L2 cache and then once the entry was valid and
- * present on disk, the entry can be committed into the cache.
- *
- * Since the cache is write-through, it's important that this function is not
- * called until the entry is present on disk and the L1 has been updated to
- * point to the entry.
- *
- * N.B. This function steals a reference to the l2_table from the caller so the
- * caller must obtain a new reference by issuing a call to
- * qed_find_l2_cache_entry().
- */
-void qed_commit_l2_cache_entry(L2TableCache *l2_cache, CachedL2Table *l2_table)
-{
-    CachedL2Table *entry;
-
-    entry = qed_find_l2_cache_entry(l2_cache, l2_table->offset);
-    if (entry) {
-        qed_unref_l2_cache_entry(entry);
-        qed_unref_l2_cache_entry(l2_table);
-        return;
-    }
-
-    /* Evict an unused cache entry so we have space.  If all entries are in use
-     * we can grow the cache temporarily and we try to shrink back down later.
-     */
-    if (l2_cache->n_entries >= MAX_L2_CACHE_SIZE) {
-        CachedL2Table *next;
-        QTAILQ_FOREACH_SAFE(entry, &l2_cache->entries, node, next) {
-            if (entry->ref > 1) {
-                continue;
-            }
-
-            QTAILQ_REMOVE(&l2_cache->entries, entry, node);
-            l2_cache->n_entries--;
-            qed_unref_l2_cache_entry(entry);
-
-            /* Stop evicting when we've shrunk back to max size */
-            if (l2_cache->n_entries < MAX_L2_CACHE_SIZE) {
-                break;
-            }
-        }
-    }
-
-    l2_cache->n_entries++;
-    QTAILQ_INSERT_TAIL(&l2_cache->entries, l2_table, node);
-}