kdump: implement reserve_crashkernel_cma

reserve_crashkernel_cma() reserves CMA ranges for the crash kernel.  If
allocating the requested size fails, try to reserve in smaller blocks.

Store the reserved ranges in the crashk_cma_ranges array and the number of
ranges in crashk_cma_cnt.

Link: https://lkml.kernel.org/r/aEqpBwOy_ekm0gw9@dwarf.suse.cz
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Donald Dutile <ddutile@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Philipp Rudo <prudo@redhat.com>
Cc: Pingfan Liu <piliu@redhat.com>
Cc: Tao Liu <ltao@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/crash_reserve.h b/include/linux/crash_reserve.h
index e784aaff2f5a163579ef872a14183b1993b590b0..7b44b41d0a20d46bcfc5f9e12abd842775927c6d 100644 (file)
--- a/include/linux/crash_reserve.h
+++ b/include/linux/crash_reserve.h
@@ -13,12 +13,24 @@
  */
 extern struct resource crashk_res;
 extern struct resource crashk_low_res;
+extern struct range crashk_cma_ranges[];
+#if defined(CONFIG_CMA) && defined(CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION)
+#define CRASHKERNEL_CMA
+#define CRASHKERNEL_CMA_RANGES_MAX 4
+extern int crashk_cma_cnt;
+#else
+#define crashk_cma_cnt 0
+#define CRASHKERNEL_CMA_RANGES_MAX 0
+#endif
+
 
 int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
                unsigned long long *crash_size, unsigned long long *crash_base,
                unsigned long long *low_size, unsigned long long *cma_size,
                bool *high);
 
+void __init reserve_crashkernel_cma(unsigned long long cma_size);
+
 #ifdef CONFIG_ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
 #ifndef DEFAULT_CRASH_KERNEL_LOW_SIZE
 #define DEFAULT_CRASH_KERNEL_LOW_SIZE  (128UL << 20)

diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c
index 86ae1365d04e45cefba6416a0ebb1b00a2a3ca55..87bf4d41eabba9125ec22285a7ce49f6b4025105 100644 (file)
--- a/kernel/crash_reserve.c
+++ b/kernel/crash_reserve.c
@@ -14,6 +14,8 @@
 #include <linux/cpuhotplug.h>
 #include <linux/memblock.h>
 #include <linux/kmemleak.h>
+#include <linux/cma.h>
+#include <linux/crash_reserve.h>
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -469,6 +471,56 @@ retry:
 #endif
 }
 
+struct range crashk_cma_ranges[CRASHKERNEL_CMA_RANGES_MAX];
+#ifdef CRASHKERNEL_CMA
+int crashk_cma_cnt;
+void __init reserve_crashkernel_cma(unsigned long long cma_size)
+{
+       unsigned long long request_size = roundup(cma_size, PAGE_SIZE);
+       unsigned long long reserved_size = 0;
+
+       if (!cma_size)
+               return;
+
+       while (cma_size > reserved_size &&
+              crashk_cma_cnt < CRASHKERNEL_CMA_RANGES_MAX) {
+
+               struct cma *res;
+
+               if (cma_declare_contiguous(0, request_size, 0, 0, 0, false,
+                                      "crashkernel", &res)) {
+                       /* reservation failed, try half-sized blocks */
+                       if (request_size <= PAGE_SIZE)
+                               break;
+
+                       request_size = roundup(request_size / 2, PAGE_SIZE);
+                       continue;
+               }
+
+               crashk_cma_ranges[crashk_cma_cnt].start = cma_get_base(res);
+               crashk_cma_ranges[crashk_cma_cnt].end =
+                       crashk_cma_ranges[crashk_cma_cnt].start +
+                       cma_get_size(res) - 1;
+               ++crashk_cma_cnt;
+               reserved_size += request_size;
+       }
+
+       if (cma_size > reserved_size)
+               pr_warn("crashkernel CMA reservation failed: %lld MB requested, %lld MB reserved in %d ranges\n",
+                       cma_size >> 20, reserved_size >> 20, crashk_cma_cnt);
+       else
+               pr_info("crashkernel CMA reserved: %lld MB in %d ranges\n",
+                       reserved_size >> 20, crashk_cma_cnt);
+}
+
+#else /* CRASHKERNEL_CMA */
+void __init reserve_crashkernel_cma(unsigned long long cma_size)
+{
+       if (cma_size)
+               pr_warn("crashkernel CMA reservation not supported\n");
+}
+#endif
+
 #ifndef HAVE_ARCH_ADD_CRASH_RES_TO_IOMEM_EARLY
 static __init int insert_crashkernel_resources(void)
 {