mirror of https://gitee.com/openkylin/linux.git
[PATCH] kdump: dynamic per cpu allocation of memory for saving cpu registers
- In case of system crash, current state of cpu registers is saved in memory in elf note format. So far memory for storing elf notes was being allocated statically for NR_CPUS. - This patch introduces dynamic allocation of memory for storing elf notes. It uses alloc_percpu() interface. This should lead to better memory usage. - Introduced based on Andi Kleen's and Eric W. Biederman's suggestions. - This patch also moves memory allocation for elf notes from architecture dependent portion to architecture independent portion. Now crash_notes is architecture independent. The whole idea is that size of memory to be allocated per cpu (MAX_NOTE_BYTES) can be architecture dependent and allocation of this memory can be architecture independent. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Vivek Goyal
Linus Torvalds
parent
8240941157
commit
cc57165874
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@ -25,7 +25,6 @@
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#include <mach_ipi.h>
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note_buf_t crash_notes[NR_CPUS];
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/* This keeps a track of which one is crashing cpu. */
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static int crashing_cpu;
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@ -72,7 +71,9 @@ static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
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* squirrelled away. ELF notes happen to provide
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* all of that that no need to invent something new.
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*/
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buf = &crash_notes[cpu][0];
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buf = (u32*)per_cpu_ptr(crash_notes, cpu);
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if (!buf)
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return;
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memset(&prstatus, 0, sizeof(prstatus));
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prstatus.pr_pid = current->pid;
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elf_core_copy_regs(&prstatus.pr_reg, regs);
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@ -28,12 +28,6 @@ typedef NORET_TYPE void (*relocate_new_kernel_t)(
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const extern unsigned char relocate_new_kernel[];
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const extern unsigned int relocate_new_kernel_size;
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/*
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* Provide a dummy crash_notes definition while crash dump arrives to ppc.
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* This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
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*/
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note_buf_t crash_notes[NR_CPUS];
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void machine_shutdown(void)
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{
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if (ppc_md.machine_shutdown)
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@ -10,8 +10,6 @@
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#include <linux/threads.h>
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#include <linux/kexec.h>
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note_buf_t crash_notes[NR_CPUS];
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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}
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@ -19,8 +19,6 @@
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#include <asm/nmi.h>
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#include <asm/hw_irq.h>
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note_buf_t crash_notes[NR_CPUS];
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void machine_crash_shutdown(struct pt_regs *regs)
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{
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/* This function is only called after the system
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@ -26,8 +26,5 @@
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#define KEXEC_ARCH KEXEC_ARCH_386
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#define MAX_NOTE_BYTES 1024
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typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
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extern note_buf_t crash_notes[];
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#endif /* _I386_KEXEC_H */
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@ -38,9 +38,6 @@
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#ifdef CONFIG_KEXEC
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#define MAX_NOTE_BYTES 1024
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typedef u32 note_buf_t[MAX_NOTE_BYTES / sizeof(u32)];
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extern note_buf_t crash_notes[];
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#ifdef __powerpc64__
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extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
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@ -35,8 +35,5 @@
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#define KEXEC_ARCH KEXEC_ARCH_S390
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#define MAX_NOTE_BYTES 1024
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typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
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extern note_buf_t crash_notes[];
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#endif /*_S390_KEXEC_H */
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@ -26,8 +26,5 @@
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#define KEXEC_ARCH KEXEC_ARCH_X86_64
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#define MAX_NOTE_BYTES 1024
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typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
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extern note_buf_t crash_notes[];
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#endif /* _X86_64_KEXEC_H */
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@ -125,6 +125,8 @@ extern struct kimage *kexec_image;
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/* Location of a reserved region to hold the crash kernel.
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*/
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extern struct resource crashk_res;
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typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
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extern note_buf_t *crash_notes;
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#else /* !CONFIG_KEXEC */
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struct pt_regs;
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@ -26,6 +26,9 @@
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#include <asm/system.h>
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#include <asm/semaphore.h>
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/* Per cpu memory for storing cpu states in case of system crash. */
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note_buf_t* crash_notes;
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/* Location of the reserved area for the crash kernel */
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struct resource crashk_res = {
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.name = "Crash kernel",
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@ -1060,3 +1063,16 @@ void crash_kexec(struct pt_regs *regs)
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xchg(&kexec_lock, 0);
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}
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}
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static int __init crash_notes_memory_init(void)
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{
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/* Allocate memory for saving cpu registers. */
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crash_notes = alloc_percpu(note_buf_t);
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if (!crash_notes) {
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printk("Kexec: Memory allocation for saving cpu register"
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" states failed\n");
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return -ENOMEM;
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}
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return 0;
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}
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module_init(crash_notes_memory_init)
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