* [08/45] mm, x86: Saving vmcore with non-lazy freeing of vmas
[not found] <20101119214439.GA26350@kroah.com>
@ 2010-11-19 21:42 ` Greg KH
2010-11-20 2:16 ` [Stable-review] " Ben Hutchings
2010-11-19 21:42 ` [14/45] x86, kdump: Change copy_oldmem_page() to use cached addressing Greg KH
1 sibling, 1 reply; 4+ messages in thread
From: Greg KH @ 2010-11-19 21:42 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Ingo Molnar, kexec, Cliff Wickman, akpm, torvalds, stable-review,
alan
2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------
From: Cliff Wickman <cpw@sgi.com>
commit 3ee48b6af49cf534ca2f481ecc484b156a41451d upstream.
During the reading of /proc/vmcore the kernel is doing
ioremap()/iounmap() repeatedly. And the buildup of un-flushed
vm_area_struct's is causing a great deal of overhead. (rb_next()
is chewing up most of that time).
This solution is to provide function set_iounmap_nonlazy(). It
causes a subsequent call to iounmap() to immediately purge the
vma area (with try_purge_vmap_area_lazy()).
With this patch we have seen the time for writing a 250MB
compressed dump drop from 71 seconds to 44 seconds.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: kexec@lists.infradead.org
LKML-Reference: <E1OwHZ4-0005WK-Tw@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/include/asm/io.h | 1 +
arch/x86/kernel/crash_dump_64.c | 1 +
mm/vmalloc.c | 9 +++++++++
3 files changed, 11 insertions(+)
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -172,6 +172,7 @@ static inline void __iomem *ioremap(reso
extern void iounmap(volatile void __iomem *addr);
+extern void set_iounmap_nonlazy(void);
#ifdef CONFIG_X86_32
# include "io_32.h"
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -46,6 +46,7 @@ ssize_t copy_oldmem_page(unsigned long p
} else
memcpy(buf, vaddr + offset, csize);
+ set_iounmap_nonlazy();
iounmap(vaddr);
return csize;
}
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -513,6 +513,15 @@ static atomic_t vmap_lazy_nr = ATOMIC_IN
static void purge_fragmented_blocks_allcpus(void);
/*
+ * called before a call to iounmap() if the caller wants vm_area_struct's
+ * immediately freed.
+ */
+void set_iounmap_nonlazy(void)
+{
+ atomic_set(&vmap_lazy_nr, lazy_max_pages()+1);
+}
+
+/*
* Purges all lazily-freed vmap areas.
*
* If sync is 0 then don't purge if there is already a purge in progress.
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^ permalink raw reply [flat|nested] 4+ messages in thread* [14/45] x86, kdump: Change copy_oldmem_page() to use cached addressing
[not found] <20101119214439.GA26350@kroah.com>
2010-11-19 21:42 ` [08/45] mm, x86: Saving vmcore with non-lazy freeing of vmas Greg KH
@ 2010-11-19 21:42 ` Greg KH
1 sibling, 0 replies; 4+ messages in thread
From: Greg KH @ 2010-11-19 21:42 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Ingo Molnar, kexec, Cliff Wickman, Eric W. Biederman, akpm,
torvalds, stable-review, alan
2.6.32-stable review patch. If anyone has any objections, please let us know.
------------------
From: Cliff Wickman <cpw@sgi.com>
commit 37a2f9f30a360fb03522d15c85c78265ccd80287 upstream.
The copy of /proc/vmcore to a user buffer proceeds much faster
if the kernel addresses memory as cached.
With this patch we have seen an increase in transfer rate from
less than 15MB/s to 80-460MB/s, depending on size of the
transfer. This makes a big difference in time needed to save a
system dump.
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: kexec@lists.infradead.org
LKML-Reference: <E1OtMLz-0001yp-Ia@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
arch/x86/kernel/crash_dump_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -34,7 +34,7 @@ ssize_t copy_oldmem_page(unsigned long p
if (!csize)
return 0;
- vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+ vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
if (!vaddr)
return -ENOMEM;
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