11:59 p.m.
This patch set implements support zram on x86_64 for recent fedora
kernel, tested on kernel-5.6.7-200.fc31.x86_64.
I actually have other patch set for RHEL7 and RHEL8 kernels as well,
but I want to do them later because the change for it is quite large
and I think it necessary to first refactor zram code, e.g. by moving
the zram code in diskdump.c into zram.c.
HATAYAMA Daisuke (5):
mm/zram: introduce MAX_POSSIBLE_PHYSMEM_BITS
zram/swap cache: treat xarray case
zram: fix wrongly recognizing lzo-rle as lzo
zram: try loading debuginfo for zram when needed
zram: fix failure invalid structure member offset: zram_table_flag
defs.h | 7 ++++++-
diskdump.c | 23 +++++++++++++++++++++--
memory.c | 4 ----
3 files changed, 27 insertions(+), 7 deletions(-)
--
2.25.4
11:59 p.m.
New subject: [PATCH 1/5] mm/zram: introduce MAX_POSSIBLE_PHYSMEM_BITS
_PFN_BITS is defined with MAX_POSSIBLE_PHYSMEM_BITS that is defined in
the arch specific way particular on x86/x86-64. See the following
commit in the krenel git repository for reference:
02390b87a9459937cdb299e6b34ff33992512ec7
mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS
---
defs.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/defs.h b/defs.h
index aba58ff..e84c346 100644
--- a/defs.h
+++ b/defs.h
@@ -3531,6 +3531,8 @@ struct arm64_stackframe {
machdep->machspec->last_p4d_read = (ulong)(P4D); \
}
+#define MAX_POSSIBLE_PHYSMEM_BITS 52
+
/*
* PHYSICAL_PAGE_MASK changed (enlarged) between 2.4 and 2.6, so
* for safety, use the 2.6 values to generate it.
@@ -6487,7 +6489,10 @@ void diskdump_device_dump_extract(int, char *, FILE *);
ulong try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong len, ulonglong
vaddr);
#ifdef LZO
#define OBJ_TAG_BITS 1
-#define _PFN_BITS (MAX_PHYSMEM_BITS() - PAGESHIFT())
+#ifndef MAX_POSSIBLE_PHYSMEM_BITS
+#define MAX_POSSIBLE_PHYSMEM_BITS (MAX_PHYSMEM_BITS())
+#endif
+#define _PFN_BITS (MAX_POSSIBLE_PHYSMEM_BITS - PAGESHIFT())
#define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS)
#define OBJ_INDEX_MASK ((1 << OBJ_INDEX_BITS) - 1)
#define ZS_HANDLE_SIZE (sizeof(unsigned long))
--
1.8.3.1
11:59 p.m.
New subject: [PATCH 2/5] zram/swap cache: treat xarray case
In recent kernels, radix_tree_root has been replaced by
xarray. lookup_swap_cache() needs to switch depending on what type
i_pages in address_space structure has.
See the following commit of linux kernel git repository for reference:
eb797a8ee0ab4cd03df556980ce7bf167cadaa50
page cache: Rearrange address_space
---
diskdump.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/diskdump.c b/diskdump.c
index 572ef70..88d0dee 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2657,6 +2657,11 @@ lookup_swap_cache(ulonglong pte_val, unsigned char *zram_buf)
ulong swp_type, swp_space, page;
struct list_pair lp;
physaddr_t paddr;
+ static int is_xarray = -1;
+
+ if (is_xarray < 0) {
+ is_xarray = STREQ(MEMBER_TYPE_NAME("address_space", "i_pages"),
"xarray");
+ }
swp_type = __swp_type(pte_val);
if (THIS_KERNEL_VERSION >= LINUX(2,6,0)) {
@@ -2675,7 +2680,7 @@ lookup_swap_cache(ulonglong pte_val, unsigned char *zram_buf)
swp_space += (swp_offset >> SWAP_ADDRESS_SPACE_SHIFT) * SIZE(address_space);
lp.index = swp_offset;
- if (do_radix_tree(swp_space, RADIX_TREE_SEARCH, &lp)){
+ if ((is_xarray ? do_xarray : do_radix_tree)(swp_space, RADIX_TREE_SEARCH, &lp)) {
readmem((ulong)lp.value, KVADDR, &page, sizeof(void *),
"swap_cache page", FAULT_ON_ERROR);
if (!is_page_ptr(page, &paddr)) {
--
1.8.3.1
11:59 p.m.
New subject: [PATCH 3/5] zram: fix wrongly recognizing lzo-rle as lzo
As of the following commit merged at v5.1, zram uses lzo-rle by
default:
ce82f19fd5809f0cf87ea9f753c5cc65ca0673d6
zram: default to lzo-rle instead of lzo
The problem fixed by this commit is that the current implementation
wrongly recognizes lzo-rle as lzo because it pays attention to the
first 3 bytes of the name only.
Note that lzo-rle is implemented by kernel and not supported by
user-land library, say lzo-devel. To support lzo-rle, it's necessary
to import tthe kernel's lzo library into crash utility.
---
diskdump.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/diskdump.c b/diskdump.c
index 88d0dee..40d3eb7 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2738,7 +2738,7 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
readmem(zram + OFFSET(zram_compressor), KVADDR, name,
sizeof(name), "zram compressor", FAULT_ON_ERROR);
- if (!strncmp(name, "lzo", strlen("lzo"))) {
+ if (STREQ(name, "lzo")) {
if (!(dd->flags & LZO_SUPPORTED)) {
if (lzo_init() == LZO_E_OK)
dd->flags |= LZO_SUPPORTED;
--
1.8.3.1
11:59 p.m.
New subject: [PATCH 4/5] zram: try loading debuginfo for zram when needed
zram could be provided as a module. Then, debuginfo for zram-related
data structures are not contained in vmlinux, which needs to be loaded
after debuginfo for zram module is loaded. This patch makes
try_zram_decompress() tries to load debuginfo for zram.
---
diskdump.c | 12 ++++++++++++
memory.c | 4 ----
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/diskdump.c b/diskdump.c
index 40d3eb7..65f43ff 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2586,6 +2586,15 @@ diskdump_device_dump_info(FILE *ofp)
}
#ifdef LZO
+static void
+zram_init(void)
+{
+ MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
+ MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
+ MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags");
+ STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry");
+}
+
static unsigned char *
zram_object_addr(ulong pool, ulong handle, unsigned char *zram_buf)
{
@@ -2708,6 +2717,9 @@ try_zram_decompress(ulonglong pte_val, unsigned char *buf, ulong
len, ulonglong
unsigned char *zram_buf = NULL;
unsigned char *outbuf = NULL;
+ if (INVALID_MEMBER(zram_compressor))
+ zram_init();
+
off = PAGEOFFSET(vaddr);
if (!symbol_exists("swap_info"))
return 0;
diff --git a/memory.c b/memory.c
index 2d9b50a..2bea128 100644
--- a/memory.c
+++ b/memory.c
@@ -487,10 +487,6 @@ vm_init(void)
"swap_info_struct", "old_block_size");
MEMBER_OFFSET_INIT(swap_info_struct_bdev, "swap_info_struct",
"bdev");
- MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
- MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
- MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags");
- STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry");
MEMBER_OFFSET_INIT(zspoll_size_class, "zs_pool", "size_class");
MEMBER_OFFSET_INIT(size_class_size, "size_class", "size");
--
1.8.3.1
11:59 p.m.
New subject: [PATCH 5/5] zram: fix failure invalid structure member offset: zram_table_flag
On vmcore of the kernel version 4.18.0-147.5.1.el8_1.x86_64, there is
the following error when trying to read the user-space memory that is
swapped out into some zram device:
crash> rd -u 0x00007f9b88bea000
rd: invalid structure member offset: zram_table_flag
FILE: diskdump.c LINE: 2784 FUNCTION: try_zram_decompress()
[./crash] error trace: 47aaa2 => 571900 => 53a3f1 => 53a373
53a373: OFFSET_verify.part.27+51
53a3f1: OFFSET_verify+49
571900: try_zram_decompress+1808
47aaa2: readmem+2562
rd: invalid structure member offset: zram_table_flag
FILE: diskdump.c LINE: 2784 FUNCTION: try_zram_decompress()
This message means that there is no flags member in zram_table_entry
structure. The flags member is renamed from the former value by the
following commit for refactoring:
7e5292831b346bacb05558ca385cae366187314c
zram: refactor flags and writeback stuff
Let's initialize offset_table.zram_table_flags by value member as
well.
---
diskdump.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/diskdump.c b/diskdump.c
index 65f43ff..63a08a1 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2592,6 +2592,8 @@ zram_init(void)
MEMBER_OFFSET_INIT(zram_mempoll, "zram", "mem_pool");
MEMBER_OFFSET_INIT(zram_compressor, "zram", "compressor");
MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "flags");
+ if (INVALID_MEMBER(zram_table_flag))
+ MEMBER_OFFSET_INIT(zram_table_flag, "zram_table_entry", "value");
STRUCT_SIZE_INIT(zram_table_entry, "zram_table_entry");
}
--
1.8.3.1
2:23 a.m.
Hi,
I put some stuff I used in developing the patch set.
Please use them if you think them helpful for reviewing.
https://github.com/d-hatayama/some_stuff_for_crash_zram_devel
________________________________________
差出人: HATAYAMA Daisuke <d.hatayama(a)fujitsu.com>
送信日時: 2020年5月27日 13:59
宛先: crash-utility(a)redhat.com
CC: Hatayama, Daisuke/畑山 大輔
件名: [PATCH 0/5] crash: Support zram on x86_64 for recent fedora kernel
This patch set implements support zram on x86_64 for recent fedora
kernel, tested on kernel-5.6.7-200.fc31.x86_64.
I actually have other patch set for RHEL7 and RHEL8 kernels as well,
but I want to do them later because the change for it is quite large
and I think it necessary to first refactor zram code, e.g. by moving
the zram code in diskdump.c into zram.c.
HATAYAMA Daisuke (5):
mm/zram: introduce MAX_POSSIBLE_PHYSMEM_BITS
zram/swap cache: treat xarray case
zram: fix wrongly recognizing lzo-rle as lzo
zram: try loading debuginfo for zram when needed
zram: fix failure invalid structure member offset: zram_table_flag
defs.h | 7 ++++++-
diskdump.c | 23 +++++++++++++++++++++--
memory.c | 4 ----
3 files changed, 27 insertions(+), 7 deletions(-)
--
2.25.4
8:52 a.m.
New subject: [PATCH 0/5] crash: Support zram on x86_64 for recent fedora kernel
----- Original Message -----
This patch set implements support zram on x86_64 for recent fedora
kernel, tested on kernel-5.6.7-200.fc31.x86_64.
I actually have other patch set for RHEL7 and RHEL8 kernels as well,
but I want to do them later because the change for it is quite large
and I think it necessary to first refactor zram code, e.g. by moving
the zram code in diskdump.c into zram.c.
HATAYAMA Daisuke (5):
mm/zram: introduce MAX_POSSIBLE_PHYSMEM_BITS
zram/swap cache: treat xarray case
zram: fix wrongly recognizing lzo-rle as lzo
zram: try loading debuginfo for zram when needed
zram: fix failure invalid structure member offset: zram_table_flag
defs.h | 7 ++++++-
diskdump.c | 23 +++++++++++++++++++++--
memory.c | 4 ----
3 files changed, 27 insertions(+), 7 deletions(-)
Hi Daisuke,
This all looks good -- queued for crash-7.2.9:
https://github.com/crash-utility/crash/commit/3b0ab4634de89ff23ace1d4172a...
Thanks,
Dave
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HATAYAMA Daisuke