OpenZFS restructuring - move platform specific sources

Move platform specific Linux source under module/os/linux/
and update the build system accordingly.  Additional code
restructuring will follow to make the common code fully
portable.
    
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matthew Macy <mmacy@FreeBSD.org>
Closes #9206

module/os/linux/spl/spl-vmem.c

@@ -0,0 +1,135 @@
+/*
+ *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
+ *  Copyright (C) 2007 The Regents of the University of California.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://zfsonlinux.org/>.
+ *
+ *  The SPL 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; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL 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 the SPL.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sys/debug.h>
+#include <sys/vmem.h>
+#include <sys/kmem_cache.h>
+#include <sys/shrinker.h>
+#include <linux/module.h>
+
+vmem_t *heap_arena = NULL;
+EXPORT_SYMBOL(heap_arena);
+
+vmem_t *zio_alloc_arena = NULL;
+EXPORT_SYMBOL(zio_alloc_arena);
+
+vmem_t *zio_arena = NULL;
+EXPORT_SYMBOL(zio_arena);
+
+#define	VMEM_FLOOR_SIZE		(4 * 1024 * 1024)	/* 4MB floor */
+
+/*
+ * Return approximate virtual memory usage based on these assumptions:
+ *
+ * 1) The major SPL consumer of virtual memory is the kmem cache.
+ * 2) Memory allocated with vmem_alloc() is short lived and can be ignored.
+ * 3) Allow a 4MB floor as a generous pad given normal consumption.
+ * 4) The spl_kmem_cache_sem only contends with cache create/destroy.
+ */
+size_t
+vmem_size(vmem_t *vmp, int typemask)
+{
+	spl_kmem_cache_t *skc;
+	size_t alloc = VMEM_FLOOR_SIZE;
+
+	if ((typemask & VMEM_ALLOC) && (typemask & VMEM_FREE))
+		return (VMALLOC_TOTAL);
+
+
+	down_read(&spl_kmem_cache_sem);
+	list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
+		if (skc->skc_flags & KMC_VMEM)
+			alloc += skc->skc_slab_size * skc->skc_slab_total;
+	}
+	up_read(&spl_kmem_cache_sem);
+
+	if (typemask & VMEM_ALLOC)
+		return (MIN(alloc, VMALLOC_TOTAL));
+	else if (typemask & VMEM_FREE)
+		return (MAX(VMALLOC_TOTAL - alloc, 0));
+	else
+		return (0);
+}
+EXPORT_SYMBOL(vmem_size);
+
+/*
+ * Public vmem_alloc(), vmem_zalloc() and vmem_free() interfaces.
+ */
+void *
+spl_vmem_alloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+	flags |= KM_VMEM;
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_alloc);
+
+void *
+spl_vmem_zalloc(size_t size, int flags, const char *func, int line)
+{
+	ASSERT0(flags & ~KM_PUBLIC_MASK);
+
+	flags |= (KM_VMEM | KM_ZERO);
+
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
+#else
+	return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_zalloc);
+
+void
+spl_vmem_free(const void *buf, size_t size)
+{
+#if !defined(DEBUG_KMEM)
+	return (spl_kmem_free_impl(buf, size));
+#elif !defined(DEBUG_KMEM_TRACKING)
+	return (spl_kmem_free_debug(buf, size));
+#else
+	return (spl_kmem_free_track(buf, size));
+#endif
+}
+EXPORT_SYMBOL(spl_vmem_free);
+
+int
+spl_vmem_init(void)
+{
+	return (0);
+}
+
+void
+spl_vmem_fini(void)
+{
+}