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-rw-r--r--mysys/my_lockmem.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/mysys/my_lockmem.c b/mysys/my_lockmem.c
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+++ b/mysys/my_lockmem.c
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+/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
+ Copyright (c) 2022, MariaDB Corporation.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; version 2 of the License.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
+
+/* Alloc a block of locked memory (memory protected against swap) */
+
+#include "mysys_priv.h"
+#include "mysys_err.h"
+#include "aligned.h"
+#include <my_list.h>
+
+#ifdef HAVE_MLOCK
+
+struct st_mem_list
+{
+ LIST list;
+ uchar *page;
+ uint size;
+};
+
+LIST *mem_list;
+
+uchar *my_malloc_lock(size_t size, myf MyFlags)
+{
+ int success;
+ uint pagesize= my_system_page_size;
+ uchar *ptr;
+ struct st_mem_list *element;
+ DBUG_ENTER("my_malloc_lock");
+
+ size=((size-1) & ~(pagesize-1))+pagesize;
+ if (!(ptr=aligned_malloc(size,pagesize)))
+ {
+ if (MyFlags & (MY_FAE+MY_WME))
+ my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_FATAL), size);
+ DBUG_RETURN(0);
+ }
+ success = mlock((uchar*) ptr,size);
+ if (success != 0 && geteuid() == 0)
+ {
+ DBUG_PRINT("warning",("Failed to lock memory. errno %d\n",
+ errno));
+ fprintf(stderr, "Warning: Failed to lock memory. errno %d\n",
+ errno);
+ }
+ else
+ {
+ /* Add block in a list for munlock */
+ if (!(element=(struct st_mem_list*) my_malloc(sizeof(*element),MyFlags)))
+ {
+ (void) munlock((uchar*) ptr,size);
+ free(ptr);
+ DBUG_RETURN(0);
+ }
+ element->list.data=(uchar*) element;
+ element->page=ptr;
+ element->size=size;
+ mysql_mutex_lock(&THR_LOCK_malloc);
+ mem_list=list_add(mem_list,&element->list);
+ mysql_mutex_unlock(&THR_LOCK_malloc);
+ update_malloc_size((longlong) size, 0);
+ }
+ DBUG_RETURN(ptr);
+}
+
+
+void my_free_lock(uchar *ptr)
+{
+ LIST *list;
+ struct st_mem_list *element=0;
+
+ mysql_mutex_lock(&THR_LOCK_malloc);
+ for (list=mem_list ; list ; list=list->next)
+ {
+ element=(struct st_mem_list*) list->data;
+ if (ptr == element->page)
+ { /* Found locked mem */
+ (void) munlock((uchar*) ptr,element->size);
+ mem_list=list_delete(mem_list,list);
+ update_malloc_size(- (longlong) element->size, 0);
+ break;
+ }
+ }
+ mysql_mutex_unlock(&THR_LOCK_malloc);
+ my_free(element);
+ aligned_free(ptr); /* Free even if not locked */
+}
+
+#endif /* HAVE_MLOCK */