The patch titled
printk: allocate kernel log buffer earlier
has been added to the -mm tree. Its filename is
printk-allocate-kernel-log-buffer-earlier-v2.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: printk: allocate kernel log buffer earlier
From: Mike Travis <travis@xxxxxxx>
On larger systems, because of the numerous ACPI, Bootmem and EFI messages,
the static log buffer overflows before the larger one specified by the
log_buf_len param is allocated. Minimize the overflow by allocating the
new log buffer as soon as possible.
On kernels without memblock, a later call to setup_log_buf from
kernel/init.c is the fallback.
Signed-off-by: Mike Travis <travis@xxxxxxx>
Cc: Yinghai Lu <yhlu.kernel@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Jack Steiner <steiner@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/setup.c | 2
include/linux/printk.h | 4 +
init/main.c | 1
kernel/printk.c | 87 +++++++++++++++++++++++++-------------
4 files changed, 65 insertions(+), 29 deletions(-)
diff -puN arch/x86/kernel/setup.c~printk-allocate-kernel-log-buffer-earlier-v2 arch/x86/kernel/setup.c
--- a/arch/x86/kernel/setup.c~printk-allocate-kernel-log-buffer-earlier-v2
+++ a/arch/x86/kernel/setup.c
@@ -946,6 +946,8 @@ void __init setup_arch(char **cmdline_p)
if (init_ohci1394_dma_early)
init_ohci1394_dma_on_all_controllers();
#endif
+ /* Allocate bigger log buffer */
+ setup_log_buf(1);
reserve_initrd();
diff -puN include/linux/printk.h~printk-allocate-kernel-log-buffer-earlier-v2 include/linux/printk.h
--- a/include/linux/printk.h~printk-allocate-kernel-log-buffer-earlier-v2
+++ a/include/linux/printk.h
@@ -1,6 +1,8 @@
#ifndef __KERNEL_PRINTK__
#define __KERNEL_PRINTK__
+#include <linux/init.h>
+
extern const char linux_banner[];
extern const char linux_proc_banner[];
@@ -89,6 +91,8 @@ int no_printk(const char *fmt, ...)
extern asmlinkage __attribute__ ((format (printf, 1, 2)))
void early_printk(const char *fmt, ...);
+void __init setup_log_buf(int early);
+
extern int printk_needs_cpu(int cpu);
extern void printk_tick(void);
diff -puN init/main.c~printk-allocate-kernel-log-buffer-earlier-v2 init/main.c
--- a/init/main.c~printk-allocate-kernel-log-buffer-earlier-v2
+++ a/init/main.c
@@ -504,6 +504,7 @@ asmlinkage void __init start_kernel(void
* These use large bootmem allocations and must precede
* kmem_cache_init()
*/
+ setup_log_buf(0);
pidhash_init();
vfs_caches_init_early();
sort_main_extable();
diff -puN kernel/printk.c~printk-allocate-kernel-log-buffer-earlier-v2 kernel/printk.c
--- a/kernel/printk.c~printk-allocate-kernel-log-buffer-earlier-v2
+++ a/kernel/printk.c
@@ -31,6 +31,7 @@
#include <linux/smp.h>
#include <linux/security.h>
#include <linux/bootmem.h>
+#include <linux/memblock.h>
#include <linux/syscalls.h>
#include <linux/kexec.h>
#include <linux/kdb.h>
@@ -167,46 +168,74 @@ void log_buf_kexec_setup(void)
}
#endif
+/* requested log_buf_len from kernel cmdline */
+static unsigned long __initdata new_log_buf_len;
+
+/* save requested log_buf_len since it's too early to process it */
static int __init log_buf_len_setup(char *str)
{
unsigned size = memparse(str, &str);
- unsigned long flags;
if (size)
size = roundup_pow_of_two(size);
- if (size > log_buf_len) {
- unsigned start, dest_idx, offset;
- char *new_log_buf;
-
- new_log_buf = alloc_bootmem(size);
- if (!new_log_buf) {
- printk(KERN_WARNING "log_buf_len: allocation failed\n");
- goto out;
- }
+ if (size > log_buf_len)
+ new_log_buf_len = size;
- spin_lock_irqsave(&logbuf_lock, flags);
- log_buf_len = size;
- log_buf = new_log_buf;
+ return 0;
+}
+early_param("log_buf_len", log_buf_len_setup);
- offset = start = min(con_start, log_start);
- dest_idx = 0;
- while (start != log_end) {
- log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
- start++;
- dest_idx++;
- }
- log_start -= offset;
- con_start -= offset;
- log_end -= offset;
- spin_unlock_irqrestore(&logbuf_lock, flags);
+void __init setup_log_buf(int early)
+{
+ unsigned long flags;
+ unsigned start, dest_idx, offset;
+ char *new_log_buf;
+ int free;
+
+ if (!new_log_buf_len)
+ return;
- printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
+ if (early) {
+ unsigned long mem;
+
+ mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
+ if (mem == MEMBLOCK_ERROR)
+ return;
+ new_log_buf = __va(mem);
}
-out:
- return 1;
-}
+ else
+ new_log_buf = alloc_bootmem_nopanic(new_log_buf_len);
+
+ if (unlikely(!new_log_buf)) {
+ pr_err("log_buf_len: %ld bytes not available\n",
+ new_log_buf_len);
+ return;
+ }
+
+ spin_lock_irqsave(&logbuf_lock, flags);
+ log_buf_len = new_log_buf_len;
+ log_buf = new_log_buf;
+ new_log_buf_len = 0;
+ free = __LOG_BUF_LEN - log_end;
+
+ offset = start = min(con_start, log_start);
+ dest_idx = 0;
+ while (start != log_end) {
+ unsigned log_idx_mask = start & (__LOG_BUF_LEN - 1);
+
+ log_buf[dest_idx] = __log_buf[log_idx_mask];
+ start++;
+ dest_idx++;
+ }
+ log_start -= offset;
+ con_start -= offset;
+ log_end -= offset;
+ spin_unlock_irqrestore(&logbuf_lock, flags);
-__setup("log_buf_len=", log_buf_len_setup);
+ pr_info("log_buf_len: %d\n", log_buf_len);
+ pr_info("early log buf free: %d(%d%%)\n",
+ free, (free * 100) / __LOG_BUF_LEN);
+}
#ifdef CONFIG_BOOT_PRINTK_DELAY
_
Patches currently in -mm which might be from travis@xxxxxxx are
bitmap-irq-add-smp_affinity_list-interface-to-proc-irq.patch
memblock-add-error-return-when-config_have_memblock-is-not-set.patch
printk-allocate-kernel-log-buffer-earlier-v2.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
