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Date: Mon, 16 Oct 2023 18:32:09 -0500
From: madvenka@...ux.microsoft.com
To: gregkh@...uxfoundation.org, pbonzini@...hat.com, rppt@...nel.org,
jgowans@...zon.com, graf@...zon.de, arnd@...db.de,
keescook@...omium.org, stanislav.kinsburskii@...il.com,
anthony.yznaga@...cle.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org, madvenka@...ux.microsoft.com,
jamorris@...ux.microsoft.com
Subject: [RFC PATCH v1 04/10] mm/prmem: Implement a page allocator for persistent memory
From: "Madhavan T. Venkataraman" <madvenka@...ux.microsoft.com>
Define the following convenience wrapper functions for allocating and
freeing pages:
- prmem_alloc_pages()
- prmem_free_pages()
The functions look similar to alloc_pages() and __free_pages(). However,
the only GFP flag that is processed is __GFP_ZERO to zero out the
allocated memory.
Signed-off-by: Madhavan T. Venkataraman <madvenka@...ux.microsoft.com>
---
include/linux/prmem.h | 7 ++++
kernel/prmem/Makefile | 1 +
kernel/prmem/prmem_allocator.c | 74 ++++++++++++++++++++++++++++++++++
kernel/prmem/prmem_init.c | 2 +
4 files changed, 84 insertions(+)
create mode 100644 kernel/prmem/prmem_allocator.c
diff --git a/include/linux/prmem.h b/include/linux/prmem.h
index f43f5b0d2b9c..108683933c82 100644
--- a/include/linux/prmem.h
+++ b/include/linux/prmem.h
@@ -75,6 +75,7 @@ extern unsigned long prmem_metadata;
extern unsigned long prmem_pa;
extern size_t prmem_size;
extern bool prmem_inited;
+extern spinlock_t prmem_lock;
/* Kernel API. */
void prmem_reserve_early(void);
@@ -83,11 +84,17 @@ void prmem_init(void);
void prmem_fini(void);
int prmem_cmdline_size(void);
+/* Allocator API. */
+struct page *prmem_alloc_pages(unsigned int order, gfp_t gfp);
+void prmem_free_pages(struct page *pages, unsigned int order);
+
/* Internal functions. */
struct prmem_region *prmem_add_region(unsigned long pa, size_t size);
bool prmem_create_pool(struct prmem_region *region, bool new_region);
void *prmem_alloc_pool(struct prmem_region *region, size_t size, int align);
void prmem_free_pool(struct prmem_region *region, void *va, size_t size);
+void *prmem_alloc_pages_locked(unsigned int order);
+void prmem_free_pages_locked(void *va, unsigned int order);
unsigned long prmem_checksum(void *start, size_t size);
bool __init prmem_validate(void);
void prmem_cmdline(char *cmdline);
diff --git a/kernel/prmem/Makefile b/kernel/prmem/Makefile
index 9b0a693bfee1..99bb19f0afd3 100644
--- a/kernel/prmem/Makefile
+++ b/kernel/prmem/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-y += prmem_parse.o prmem_reserve.o prmem_init.o prmem_region.o prmem_misc.o
+obj-y += prmem_allocator.o
diff --git a/kernel/prmem/prmem_allocator.c b/kernel/prmem/prmem_allocator.c
new file mode 100644
index 000000000000..07a5a430630c
--- /dev/null
+++ b/kernel/prmem/prmem_allocator.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Persistent-Across-Kexec memory feature (prmem) - Allocator.
+ *
+ * Copyright (C) 2023 Microsoft Corporation
+ * Author: Madhavan T. Venkataraman (madvenka@...ux.microsoft.com)
+ */
+#include <linux/prmem.h>
+
+/* Page Allocation functions. */
+
+void *prmem_alloc_pages_locked(unsigned int order)
+{
+ struct prmem_region *region;
+ void *va;
+ size_t size = (1UL << order) << PAGE_SHIFT;
+
+ list_for_each_entry(region, &prmem->regions, node) {
+ va = prmem_alloc_pool(region, size, size);
+ if (va)
+ return va;
+ }
+ return NULL;
+}
+
+struct page *prmem_alloc_pages(unsigned int order, gfp_t gfp)
+{
+ void *va;
+ size_t size = (1UL << order) << PAGE_SHIFT;
+ bool zero = !!(gfp & __GFP_ZERO);
+
+ if (!prmem_inited || order > MAX_ORDER)
+ return NULL;
+
+ spin_lock(&prmem_lock);
+ va = prmem_alloc_pages_locked(order);
+ spin_unlock(&prmem_lock);
+
+ if (va) {
+ if (zero)
+ memset(va, 0, size);
+ return virt_to_page(va);
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(prmem_alloc_pages);
+
+void prmem_free_pages_locked(void *va, unsigned int order)
+{
+ struct prmem_region *region;
+ size_t size = (1UL << order) << PAGE_SHIFT;
+ void *eva = va + size;
+ void *region_va;
+
+ list_for_each_entry(region, &prmem->regions, node) {
+ /* The region structure is at the base of the region memory. */
+ region_va = region;
+ if (va >= region_va && eva <= (region_va + region->size)) {
+ prmem_free_pool(region, va, size);
+ return;
+ }
+ }
+}
+
+void prmem_free_pages(struct page *pages, unsigned int order)
+{
+ if (!prmem_inited || order > MAX_ORDER)
+ return;
+
+ spin_lock(&prmem_lock);
+ prmem_free_pages_locked(page_to_virt(pages), order);
+ spin_unlock(&prmem_lock);
+}
+EXPORT_SYMBOL_GPL(prmem_free_pages);
diff --git a/kernel/prmem/prmem_init.c b/kernel/prmem/prmem_init.c
index 56df1e6d3ebc..d23833d296fe 100644
--- a/kernel/prmem/prmem_init.c
+++ b/kernel/prmem/prmem_init.c
@@ -9,6 +9,8 @@
bool prmem_inited;
+DEFINE_SPINLOCK(prmem_lock);
+
void __init prmem_init(void)
{
if (!prmem)
--
2.25.1
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