6:34 a.m.
The linux kernel supports the large folio for page cache by default.
But the current CRASH does not support the large folio.
So we may meet the errors when we detected the large folio sometimes,
such as in the email:
https://www.spinics.net/linux/fedora/redhat-crash-utility/msg11238.html
------------------------------
files: page_to_nid: invalid page: 0
files: page_to_nid: invalid page: 0
files: page_to_nid: invalid page: 0
files: page_to_nid: invalid page: 10
files: page_to_nid: invalid page: 10
files: page_to_nid: invalid page: 10
files: page_to_nid: invalid page: 20
files: page_to_nid: invalid page: 20
files: page_to_nid: invalid page: 20
files: page_to_nid: invalid page: 30
files: page_to_nid: invalid page: 30
files: page_to_nid: invalid page: 30
files: page_to_nid: invalid page: 40
files: page_to_nid: invalid page: 40
files: page_to_nid: invalid page: 40
files: page_to_nid: invalid page: 50
files: page_to_nid: invalid page: 50
files: page_to_nid: invalid page: 50
files: page_to_nid: invalid page: 60
files: page_to_nid: invalid page: 60
------------------------------
The first 3 patches are used to add large folio support for CRASH.
The last patch is newly version of an old patch:
it add "files -n" command.
Huang Shijie (4):
xarray: add a new parameter for do_xarray
add folio_order function
xarray: add large folio support
add "files -n" command for an inode
bpf.c | 8 +++---
defs.h | 10 ++++++-
dev.c | 4 +--
diskdump.c | 10 +++++--
filesys.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++--------
help.c | 24 ++++++++++++++++-
ipcs.c | 4 +--
kernel.c | 4 +--
memory.c | 26 ++++++++++++++++--
symbols.c | 2 ++
task.c | 4 +--
tools.c | 10 ++++---
12 files changed, 151 insertions(+), 32 deletions(-)
--
2.43.0
6:34 a.m.
New subject: [PATCH 1/4] xarray: add a new parameter for do_xarray
The xarray can be used in many kernel subsystems.
For the page cache, it can support the large folio
which needs special operations.
So this patch adds a new parameter for do_xarray, and
adds a new type field in xarray_ops to distinguish them.
Also adds macro XARRAY_TYPE_PAGE_CACHE for page cache case.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
bpf.c | 8 ++++----
defs.h | 5 ++++-
dev.c | 4 ++--
diskdump.c | 10 ++++++++--
filesys.c | 7 +++++--
ipcs.c | 4 ++--
kernel.c | 4 ++--
task.c | 4 ++--
8 files changed, 29 insertions(+), 17 deletions(-)
diff --git a/bpf.c b/bpf.c
index 2840c7d..8702596 100644
--- a/bpf.c
+++ b/bpf.c
@@ -344,7 +344,7 @@ bpf_init(struct bpf_info *bpf)
break;
case IDR_XARRAY:
bpf->progs = do_xarray(symbol_value("prog_idr") + OFFSET(idr_idr_rt),
- XARRAY_COUNT, NULL);
+ XARRAY_COUNT, NULL, 0);
break;
}
@@ -364,7 +364,7 @@ bpf_init(struct bpf_info *bpf)
break;
case IDR_XARRAY:
bpf->progs = do_xarray(symbol_value("prog_idr") + OFFSET(idr_idr_rt),
- XARRAY_GATHER, bpf->proglist);
+ XARRAY_GATHER, bpf->proglist, 0);
break;
}
}
@@ -380,7 +380,7 @@ bpf_init(struct bpf_info *bpf)
break;
case IDR_XARRAY:
bpf->maps = do_xarray(symbol_value("map_idr") + OFFSET(idr_idr_rt),
- XARRAY_COUNT, NULL);
+ XARRAY_COUNT, NULL, 0);
break;
}
@@ -400,7 +400,7 @@ bpf_init(struct bpf_info *bpf)
break;
case IDR_XARRAY:
bpf->maps = do_xarray(symbol_value("map_idr") + OFFSET(idr_idr_rt),
- XARRAY_GATHER, bpf->maplist);
+ XARRAY_GATHER, bpf->maplist, 0);
break;
}
}
diff --git a/defs.h b/defs.h
index ceed3a9..60cf56a 100644
--- a/defs.h
+++ b/defs.h
@@ -5690,6 +5690,7 @@ struct xarray_ops {
void (*entry)(ulong node, ulong slot, const char *path,
ulong index, void *private);
uint radix;
+ uint type;
void *private;
};
int do_xarray_traverse(ulong ptr, int is_root, struct xarray_ops *ops);
@@ -5995,7 +5996,9 @@ ulong do_radix_tree(ulong, int, struct list_pair *);
#define RADIX_TREE_ENTRY_MASK 3UL
#define RADIX_TREE_EXCEPTIONAL_ENTRY 2
-ulong do_xarray(ulong, int, struct list_pair *);
+ulong do_xarray(ulong, int, struct list_pair *, int);
+#define XARRAY_TYPE_PAGE_CACHE 1
+
#define XARRAY_COUNT (1)
#define XARRAY_SEARCH (2)
#define XARRAY_DUMP (3)
diff --git a/dev.c b/dev.c
index 1332b0e..23f3219 100644
--- a/dev.c
+++ b/dev.c
@@ -4487,12 +4487,12 @@ static void get_mq_diskio_from_hw_queues(ulong q, struct diskio
*dio)
if (VALID_MEMBER(request_queue_hctx_table)) {
addr = q + OFFSET(request_queue_hctx_table);
- cnt = do_xarray(addr, XARRAY_COUNT, NULL);
+ cnt = do_xarray(addr, XARRAY_COUNT, NULL, 0);
lp = (struct list_pair *)GETBUF(sizeof(struct list_pair) * (cnt + 1));
if (!lp)
error(FATAL, "fail to get memory for list_pair.\n");
lp[0].index = cnt;
- cnt = do_xarray(addr, XARRAY_GATHER, lp);
+ cnt = do_xarray(addr, XARRAY_GATHER, lp, 0);
} else {
addr = q + OFFSET(request_queue_nr_hw_queues);
readmem(addr, KVADDR, &cnt, sizeof(uint),
diff --git a/diskdump.c b/diskdump.c
index 0ff8782..f17ecec 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -2942,6 +2942,7 @@ lookup_swap_cache(ulonglong pte_val, unsigned char *zram_buf)
struct list_pair lp;
physaddr_t paddr;
static int is_xarray = -1;
+ ulong ret;
if (is_xarray < 0) {
is_xarray = STREQ(MEMBER_TYPE_NAME("address_space", "i_pages"),
"xarray");
@@ -2964,8 +2965,13 @@ 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 ((is_xarray ? do_xarray : do_radix_tree)
- (swp_space+OFFSET(address_space_page_tree), RADIX_TREE_SEARCH, &lp)) {
+
+ if (is_xarray)
+ ret = do_xarray(swp_space+OFFSET(address_space_page_tree), RADIX_TREE_SEARCH, &lp,
0);
+ else
+ ret = do_radix_tree(swp_space+OFFSET(address_space_page_tree), RADIX_TREE_SEARCH,
&lp);
+
+ if (ret) {
if ((is_xarray ? xa_is_value : radix_tree_exceptional_entry)((ulong)lp.value)) {
/* ignore shadow values */
return NULL;
diff --git a/filesys.c b/filesys.c
index 34944e2..1e070a3 100644
--- a/filesys.c
+++ b/filesys.c
@@ -2289,7 +2289,7 @@ dump_inode_page_cache_info(ulong inode)
if (root_rnode)
count = do_radix_tree(root_rnode, RADIX_TREE_DUMP_CB, &lp);
else if (xarray)
- count = do_xarray(xarray, XARRAY_DUMP_CB, &lp);
+ count = do_xarray(xarray, XARRAY_DUMP_CB, &lp, XARRAY_TYPE_PAGE_CACHE);
if (count != nrpages)
error(INFO, "%s page count: %ld nrpages: %ld\n",
@@ -4305,9 +4305,11 @@ static void do_xarray_dump_cb(ulong node, ulong slot, const char
*path,
* any chance of an overrun.
* For XARRAY_DUMP_CB, the rtp->value must be initialized as a
* callback function. The callback prototype must be: int (*)(ulong);
+ *
+ * type: different xarray use types.
*/
ulong
-do_xarray(ulong root, int flag, struct list_pair *xp)
+do_xarray(ulong root, int flag, struct list_pair *xp, int type)
{
struct do_xarray_info info = {
.count = 0,
@@ -4315,6 +4317,7 @@ do_xarray(ulong root, int flag, struct list_pair *xp)
};
struct xarray_ops ops = {
.radix = 16,
+ .type = type,
.private = &info,
};
diff --git a/ipcs.c b/ipcs.c
index 59dc9b6..9cf2418 100644
--- a/ipcs.c
+++ b/ipcs.c
@@ -1150,13 +1150,13 @@ gather_xarray_entries(ulong ipcs_idr_p)
{
long len;
- ipcs_table.cnt = do_xarray(ipcs_idr_p, XARRAY_COUNT, NULL);
+ ipcs_table.cnt = do_xarray(ipcs_idr_p, XARRAY_COUNT, NULL, 0);
if (ipcs_table.cnt) {
len = sizeof(struct list_pair) * (ipcs_table.cnt+1);
ipcs_table.lp = (struct list_pair *)GETBUF(len);
ipcs_table.lp[0].index = ipcs_table.cnt;
- ipcs_table.cnt = do_xarray(ipcs_idr_p, XARRAY_GATHER, ipcs_table.lp);
+ ipcs_table.cnt = do_xarray(ipcs_idr_p, XARRAY_GATHER, ipcs_table.lp, 0);
} else
ipcs_table.lp = NULL;
}
diff --git a/kernel.c b/kernel.c
index bb148d0..48a5f29 100644
--- a/kernel.c
+++ b/kernel.c
@@ -6813,7 +6813,7 @@ get_irq_desc_addr(int irq)
break;
case IRQ_DESC_TREE_XARRAY:
cnt = do_xarray(symbol_value("irq_desc_tree"),
- XARRAY_COUNT, NULL);
+ XARRAY_COUNT, NULL, 0);
break;
}
len = sizeof(struct list_pair) * (cnt+1);
@@ -6828,7 +6828,7 @@ get_irq_desc_addr(int irq)
break;
case IRQ_DESC_TREE_XARRAY:
cnt = do_xarray(symbol_value("irq_desc_tree"),
- XARRAY_GATHER, lp);
+ XARRAY_GATHER, lp, 0);
break;
}
diff --git a/task.c b/task.c
index ec04b55..2d9c4e4 100644
--- a/task.c
+++ b/task.c
@@ -2610,7 +2610,7 @@ refresh_xarray_task_table(void)
curpid = CURRENT_PID();
}
- count = do_xarray(tt->pid_xarray, XARRAY_COUNT, NULL);
+ count = do_xarray(tt->pid_xarray, XARRAY_COUNT, NULL, 0);
if (CRASHDEBUG(1))
console("xarray: count: %ld\n", count);
@@ -2641,7 +2641,7 @@ retry_xarray:
tt->callbacks = 0;
xp.index = 0;
xp.value = (void *)&xarray_task_callback;
- count = do_xarray(tt->pid_xarray, XARRAY_DUMP_CB, &xp);
+ count = do_xarray(tt->pid_xarray, XARRAY_DUMP_CB, &xp, 0);
if (CRASHDEBUG(1))
console("do_xarray: count: %ld tt->callbacks: %d\n", count,
tt->callbacks);
--
2.43.0
6:34 a.m.
New subject: [PATCH 2/4] add folio_order function
Add the folio_order() which keeps the same logic as kernel code,
and it will be used in the later patches.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
defs.h | 4 ++++
memory.c | 22 ++++++++++++++++++++++
symbols.c | 2 ++
3 files changed, 28 insertions(+)
diff --git a/defs.h b/defs.h
index 60cf56a..fdea94f 100644
--- a/defs.h
+++ b/defs.h
@@ -1425,6 +1425,7 @@ struct offset_table { /* stash of commonly-used
offsets */
long page_buffers;
long page_lru;
long page_pte;
+ long folio__flags_1;
long swap_info_struct_swap_file;
long swap_info_struct_swap_vfsmnt;
long swap_info_struct_flags;
@@ -2398,6 +2399,7 @@ struct size_table { /* stash of commonly-used sizes */
long probe;
long kobj_map;
long page_flags;
+ long folio__flags_1;
long module_sect_attr;
long task_struct_utime;
long task_struct_stime;
@@ -6007,6 +6009,8 @@ ulong do_xarray(ulong, int, struct list_pair *, int);
#define XARRAY_TAG_MASK (3UL)
#define XARRAY_TAG_INTERNAL (2UL)
+int folio_order(ulong folio);
+
int file_dump(ulong, ulong, ulong, int, int);
#define DUMP_FULL_NAME 0x1
#define DUMP_INODE_ONLY 0x2
diff --git a/memory.c b/memory.c
index cbc8d2f..9080332 100644
--- a/memory.c
+++ b/memory.c
@@ -547,6 +547,9 @@ vm_init(void)
MEMBER_OFFSET_INIT(page_freelist, "page", "freelist");
MEMBER_OFFSET_INIT(page_page_type, "page", "page_type");
+ MEMBER_OFFSET_INIT(folio__flags_1, "folio", "_flags_1");
+ MEMBER_SIZE_INIT(folio__flags_1, "folio", "_flags_1");
+
MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
MEMBER_OFFSET_INIT(swap_info_struct_swap_file,
@@ -5690,6 +5693,7 @@ PG_slab_flag_init(void)
#define v26_PG_private 12
+#define PG_head 6
#define PGMM_CACHED (512)
static void
@@ -20423,6 +20427,24 @@ static unsigned int oo_objects(ulong oo)
return (oo & ((1 << 16) - 1));
}
+int
+folio_order(ulong folio)
+{
+ ulong v = 0;
+
+ /* 1.) Check PG_head bit in the first page's flags. */
+ readmem(folio + OFFSET(page_flags), KVADDR, &v, sizeof(ulong),
+ "folio.page.flags", FAULT_ON_ERROR);
+ if (!(v & (1 << PG_head)))
+ return 0;
+
+ /* 2.) Get folio->_flags_1 in the second page */
+ readmem(folio + OFFSET(folio__flags_1), KVADDR, &v, sizeof(ulong),
+ "folio->_flags_1", FAULT_ON_ERROR);
+
+ return v & 0xff;
+}
+
#ifdef NOT_USED
ulong
slab_to_kmem_cache_node(struct meminfo *si, ulong slab_page)
diff --git a/symbols.c b/symbols.c
index e6865ca..19fcc03 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10451,6 +10451,7 @@ dump_offset_table(char *spec, ulong makestruct)
fprintf(fp, " page_private: %ld\n",
OFFSET(page_private));
fprintf(fp, " page_page_type: %ld\n",
OFFSET(page_page_type));
+ fprintf(fp, " folio__flags_1: %ld\n", OFFSET(folio__flags_1));
fprintf(fp, " trace_print_flags_mask: %ld\n",
OFFSET(trace_print_flags_mask));
@@ -11961,6 +11962,7 @@ dump_offset_table(char *spec, ulong makestruct)
fprintf(fp, "\n size_table:\n");
fprintf(fp, " page: %ld\n", SIZE(page));
fprintf(fp, " page_flags: %ld\n", SIZE(page_flags));
+ fprintf(fp, " folio__flags_1: %ld\n", SIZE(folio__flags_1));
fprintf(fp, " trace_print_flags: %ld\n",
SIZE(trace_print_flags));
fprintf(fp, " free_area_struct: %ld\n",
SIZE(free_area_struct));
--
2.43.0
12:46 a.m.
New subject: [PATCH 2/4] add folio_order function
Hi Huang,
Some issues were found for this patch:
On Thu, Feb 12, 2026 at 1:39 AM Huang Shijie <huangsj(a)hygon.cn> wrote:
Add the folio_order() which keeps the same logic as kernel code,
and it will be used in the later patches.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
defs.h | 4 ++++
memory.c | 22 ++++++++++++++++++++++
symbols.c | 2 ++
3 files changed, 28 insertions(+)
diff --git a/defs.h b/defs.h
index 60cf56a..fdea94f 100644
--- a/defs.h
+++ b/defs.h
@@ -1425,6 +1425,7 @@ struct offset_table { /* stash of commonly-used
offsets */
long page_buffers;
long page_lru;
long page_pte;
+ long folio__flags_1;
New members of offset_table and size_table should always be appended
to the end of the struct, not inserted in the middle. See
https://github.com/crash-utility/crash/wiki "If you add struct members
to tables" section.
long swap_info_struct_swap_file;
long swap_info_struct_swap_vfsmnt;
long swap_info_struct_flags;
@@ -2398,6 +2399,7 @@ struct size_table { /* stash of commonly-used sizes */
long probe;
long kobj_map;
long page_flags;
+ long folio__flags_1;
long module_sect_attr;
long task_struct_utime;
long task_struct_stime;
@@ -6007,6 +6009,8 @@ ulong do_xarray(ulong, int, struct list_pair *, int);
#define XARRAY_TAG_MASK (3UL)
#define XARRAY_TAG_INTERNAL (2UL)
+int folio_order(ulong folio);
+
int file_dump(ulong, ulong, ulong, int, int);
#define DUMP_FULL_NAME 0x1
#define DUMP_INODE_ONLY 0x2
diff --git a/memory.c b/memory.c
index cbc8d2f..9080332 100644
--- a/memory.c
+++ b/memory.c
@@ -547,6 +547,9 @@ vm_init(void)
MEMBER_OFFSET_INIT(page_freelist, "page", "freelist");
MEMBER_OFFSET_INIT(page_page_type, "page", "page_type");
+ MEMBER_OFFSET_INIT(folio__flags_1, "folio", "_flags_1");
+ MEMBER_SIZE_INIT(folio__flags_1, "folio", "_flags_1");
+
MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
MEMBER_OFFSET_INIT(swap_info_struct_swap_file,
@@ -5690,6 +5693,7 @@ PG_slab_flag_init(void)
#define v26_PG_private 12
+#define PG_head 6
#define PGMM_CACHED (512)
static void
@@ -20423,6 +20427,24 @@ static unsigned int oo_objects(ulong oo)
return (oo & ((1 << 16) - 1));
}
+int
+folio_order(ulong folio)
+{
+ ulong v = 0;
+
+ /* 1.) Check PG_head bit in the first page's flags. */
+ readmem(folio + OFFSET(page_flags), KVADDR, &v, sizeof(ulong),
+ "folio.page.flags", FAULT_ON_ERROR);
+ if (!(v & (1 << PG_head)))
+ return 0;
+
+ /* 2.) Get folio->_flags_1 in the second page */
+ readmem(folio + OFFSET(folio__flags_1), KVADDR, &v, sizeof(ulong),
+ "folio->_flags_1", FAULT_ON_ERROR);
+
+ return v & 0xff;
+}
I encountered some regressions for this patch. See this backtrace logs:
1)
#0 folio_order (folio=18446617889843220480) at memory.c:20433
#1 0x0000000000a1243b in do_xarray_count (node=18446617889843768752,
slot=18446617889843220480, path=0x7fffffffbbd0 "root/0/0",
index=1, private=0x7fffffffceb0) at filesys.c:4275
#2 0x00000000009be0fd in do_xarray_iter (node=18446617889843768752,
height=1, path=0x7fffffffbbd0 "root/0/0", index=0,
ops=0x7fffffffce90) at tools.c:4767
#3 0x00000000009be19c in do_xarray_iter (node=18446617890154567376,
height=2, path=0x7fffffffc220 "root/0", index=0,
ops=0x7fffffffce90) at tools.c:4774
#4 0x00000000009be19c in do_xarray_iter (node=18446617886337392040,
height=3, path=0x7fffffffc860 "root", index=0,
ops=0x7fffffffce90) at tools.c:4774
#5 0x00000000009be5ca in do_xarray_traverse
(ptr=18446744071941975336, is_root=1, ops=0x7fffffffce90) at
tools.c:4849
#6 0x0000000000a127d3 in do_xarray (root=18446744071941975336,
flag=1, xp=0x0, type=0) at filesys.c:4409
#7 0x0000000000a1c7d9 in refresh_xarray_task_table () at task.c:2613
#8 0x0000000000a16c07 in task_init () at task.c:670
#9 0x00000000009aa445 in main_loop () at main.c:799
#10 0x0000000000807add in captured_main (data=<optimized out>) at main.c:1374
#11 gdb_main (args=<optimized out>) at main.c:1407
#12 0x0000000000807b45 in gdb_main_entry (argc=2, argv=0x7fffffffd908)
at main.c:1434
#13 0x0000000000a61d0b in gdb_main_loop (argc=2, argv=0x7fffffffd908)
at gdb_interface.c:81
#14 0x00000000009aa290 in main (argc=3, argv=0x7fffffffd908) at main.c:732
(gdb) p offset_table.page_flags
$1 = 0
(gdb) p offset_table.folio__flags_1
$2 = -1
20438 if (!(v & (1 << PG_head)))
(gdb) p v
$3 = 112
crash: invalid structure member offset: folio__flags_1
FILE: memory.c LINE: 20442 FUNCTION: folio_order()
Kernel version: 4.20.0-0.rc3, also I see plenty of similar regressions
for kernels 4.18, 5.2 ...
2)
Also emerge some warnings:
bpf: invalid kernel virtual address: 0 type: "folio.page.flags"
#0 readmem (addr=0, memtype=1, buffer=0x7fffffff9998, size=8,
type=0xda350f "folio.page.flags", error_handle=1) at memory.c:2411
#1 0x0000000000a0595a in folio_order (folio=0) at memory.c:20436
#2 0x0000000000a1243b in do_xarray_count (node=0, slot=0,
path=0x7fffffff9a20 "direct", index=0, private=0x7fffffffa070)
at filesys.c:4275
#3 0x00000000009be592 in do_xarray_traverse
(ptr=18446744072013761824, is_root=1, ops=0x7fffffffa050) at
tools.c:4846
#4 0x0000000000a127d3 in do_xarray (root=18446744072013761824,
flag=1, xp=0x0, type=0) at filesys.c:4409
#5 0x0000000000a7512b in bpf_init (bpf=0x12b3e80 <bpf_info>) at bpf.c:346
#6 0x0000000000a7568f in do_bpf (flags=0, prog_id=0, map_id=0,
radix=0) at bpf.c:438
#7 0x0000000000a747ea in cmd_bpf () at bpf.c:215
#8 0x00000000009aa7e1 in exec_command () at main.c:904
#9 0x00000000009aa5d3 in main_loop () at main.c:851
#10 0x0000000000807add in captured_main (data=<optimized out>) at main.c:1374
#11 gdb_main (args=<optimized out>) at main.c:1407
#12 0x0000000000807b45 in gdb_main_entry (argc=2, argv=0x7fffffffd918)
at main.c:1434
#13 0x0000000000a61d0b in gdb_main_loop (argc=2, argv=0x7fffffffd918)
at gdb_interface.c:81
#14 0x00000000009aa290 in main (argc=3, argv=0x7fffffffd918) at main.c:732
Could you please check for those?
Thanks,
Tao Liu
+
#ifdef NOT_USED
ulong
slab_to_kmem_cache_node(struct meminfo *si, ulong slab_page)
diff --git a/symbols.c b/symbols.c
index e6865ca..19fcc03 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10451,6 +10451,7 @@ dump_offset_table(char *spec, ulong makestruct)
fprintf(fp, " page_private: %ld\n",
OFFSET(page_private));
fprintf(fp, " page_page_type: %ld\n",
OFFSET(page_page_type));
+ fprintf(fp, " folio__flags_1: %ld\n",
OFFSET(folio__flags_1));
fprintf(fp, " trace_print_flags_mask: %ld\n",
OFFSET(trace_print_flags_mask));
@@ -11961,6 +11962,7 @@ dump_offset_table(char *spec, ulong makestruct)
fprintf(fp, "\n size_table:\n");
fprintf(fp, " page: %ld\n", SIZE(page));
fprintf(fp, " page_flags: %ld\n",
SIZE(page_flags));
+ fprintf(fp, " folio__flags_1: %ld\n",
SIZE(folio__flags_1));
fprintf(fp, " trace_print_flags: %ld\n",
SIZE(trace_print_flags));
fprintf(fp, " free_area_struct: %ld\n",
SIZE(free_area_struct));
--
2.43.0
--
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8:12 p.m.
New subject: [PATCH 2/4] add folio_order function
On Mon, Feb 23, 2026 at 07:46:41PM +1300, Tao Liu wrote:
> index 60cf56a..fdea94f 100644
> --- a/defs.h
> +++ b/defs.h
> @@ -1425,6 +1425,7 @@ struct offset_table { /* stash of
commonly-used offsets */
> long page_buffers;
> long page_lru;
> long page_pte;
> + long folio__flags_1;
New members of offset_table and size_table should always be appended
to the end of the struct, not inserted in the middle. See
https://github.com/crash-utility/crash/wiki "If you add struct members
to tables" section.
okay, no problem.
> long swap_info_struct_swap_file;
> long swap_info_struct_swap_vfsmnt;
> long swap_info_struct_flags;
> @@ -2398,6 +2399,7 @@ struct size_table { /* stash of commonly-used sizes
*/
> long probe;
> long kobj_map;
> long page_flags;
> + long folio__flags_1;
> long module_sect_attr;
> long task_struct_utime;
> long task_struct_stime;
> @@ -6007,6 +6009,8 @@ ulong do_xarray(ulong, int, struct list_pair *, int);
> #define XARRAY_TAG_MASK (3UL)
> #define XARRAY_TAG_INTERNAL (2UL)
>
> +int folio_order(ulong folio);
> +
> int file_dump(ulong, ulong, ulong, int, int);
> #define DUMP_FULL_NAME 0x1
> #define DUMP_INODE_ONLY 0x2
> diff --git a/memory.c b/memory.c
> index cbc8d2f..9080332 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -547,6 +547,9 @@ vm_init(void)
> MEMBER_OFFSET_INIT(page_freelist, "page", "freelist");
> MEMBER_OFFSET_INIT(page_page_type, "page",
"page_type");
>
> + MEMBER_OFFSET_INIT(folio__flags_1, "folio",
"_flags_1");
> + MEMBER_SIZE_INIT(folio__flags_1, "folio", "_flags_1");
> +
> MEMBER_OFFSET_INIT(mm_struct_pgd, "mm_struct", "pgd");
>
> MEMBER_OFFSET_INIT(swap_info_struct_swap_file,
> @@ -5690,6 +5693,7 @@ PG_slab_flag_init(void)
>
> #define v26_PG_private 12
>
> +#define PG_head 6
> #define PGMM_CACHED (512)
>
> static void
> @@ -20423,6 +20427,24 @@ static unsigned int oo_objects(ulong oo)
> return (oo & ((1 << 16) - 1));
> }
>
> +int
> +folio_order(ulong folio)
> +{
> + ulong v = 0;
> +
> + /* 1.) Check PG_head bit in the first page's flags. */
> + readmem(folio + OFFSET(page_flags), KVADDR, &v, sizeof(ulong),
> + "folio.page.flags", FAULT_ON_ERROR);
> + if (!(v & (1 << PG_head)))
> + return 0;
> +
> + /* 2.) Get folio->_flags_1 in the second page */
> + readmem(folio + OFFSET(folio__flags_1), KVADDR, &v, sizeof(ulong),
> + "folio->_flags_1", FAULT_ON_ERROR);
> +
> + return v & 0xff;
> +}
I encountered some regressions for this patch. See this backtrace logs:
1)
#0 folio_order (folio=18446617889843220480) at memory.c:20433
#1 0x0000000000a1243b in do_xarray_count (node=18446617889843768752,
slot=18446617889843220480, path=0x7fffffffbbd0 "root/0/0",
index=1, private=0x7fffffffceb0) at filesys.c:4275
#2 0x00000000009be0fd in do_xarray_iter (node=18446617889843768752,
height=1, path=0x7fffffffbbd0 "root/0/0", index=0,
ops=0x7fffffffce90) at tools.c:4767
#3 0x00000000009be19c in do_xarray_iter (node=18446617890154567376,
height=2, path=0x7fffffffc220 "root/0", index=0,
ops=0x7fffffffce90) at tools.c:4774
#4 0x00000000009be19c in do_xarray_iter (node=18446617886337392040,
height=3, path=0x7fffffffc860 "root", index=0,
ops=0x7fffffffce90) at tools.c:4774
#5 0x00000000009be5ca in do_xarray_traverse
(ptr=18446744071941975336, is_root=1, ops=0x7fffffffce90) at
tools.c:4849
#6 0x0000000000a127d3 in do_xarray (root=18446744071941975336,
flag=1, xp=0x0, type=0) at filesys.c:4409
#7 0x0000000000a1c7d9 in refresh_xarray_task_table () at task.c:2613
#8 0x0000000000a16c07 in task_init () at task.c:670
#9 0x00000000009aa445 in main_loop () at main.c:799
#10 0x0000000000807add in captured_main (data=<optimized out>) at main.c:1374
#11 gdb_main (args=<optimized out>) at main.c:1407
#12 0x0000000000807b45 in gdb_main_entry (argc=2, argv=0x7fffffffd908)
at main.c:1434
#13 0x0000000000a61d0b in gdb_main_loop (argc=2, argv=0x7fffffffd908)
at gdb_interface.c:81
#14 0x00000000009aa290 in main (argc=3, argv=0x7fffffffd908) at main.c:732
(gdb) p offset_table.page_flags
$1 = 0
(gdb) p offset_table.folio__flags_1
$2 = -1
20438 if (!(v & (1 << PG_head)))
(gdb) p v
$3 = 112
crash: invalid structure member offset: folio__flags_1
FILE: memory.c LINE: 20442 FUNCTION: folio_order()
Kernel version: 4.20.0-0.rc3, also I see plenty of similar regressions
for kernels 4.18, 5.2 ...
2)
Also emerge some warnings:
bpf: invalid kernel virtual address: 0 type: "folio.page.flags"
#0 readmem (addr=0, memtype=1, buffer=0x7fffffff9998, size=8,
type=0xda350f "folio.page.flags", error_handle=1) at memory.c:2411
#1 0x0000000000a0595a in folio_order (folio=0) at memory.c:20436
#2 0x0000000000a1243b in do_xarray_count (node=0, slot=0,
path=0x7fffffff9a20 "direct", index=0, private=0x7fffffffa070)
at filesys.c:4275
#3 0x00000000009be592 in do_xarray_traverse
(ptr=18446744072013761824, is_root=1, ops=0x7fffffffa050) at
tools.c:4846
#4 0x0000000000a127d3 in do_xarray (root=18446744072013761824,
flag=1, xp=0x0, type=0) at filesys.c:4409
#5 0x0000000000a7512b in bpf_init (bpf=0x12b3e80 <bpf_info>) at bpf.c:346
#6 0x0000000000a7568f in do_bpf (flags=0, prog_id=0, map_id=0,
radix=0) at bpf.c:438
#7 0x0000000000a747ea in cmd_bpf () at bpf.c:215
#8 0x00000000009aa7e1 in exec_command () at main.c:904
#9 0x00000000009aa5d3 in main_loop () at main.c:851
#10 0x0000000000807add in captured_main (data=<optimized out>) at main.c:1374
#11 gdb_main (args=<optimized out>) at main.c:1407
#12 0x0000000000807b45 in gdb_main_entry (argc=2, argv=0x7fffffffd918)
at main.c:1434
#13 0x0000000000a61d0b in gdb_main_loop (argc=2, argv=0x7fffffffd918)
at gdb_interface.c:81
#14 0x00000000009aa290 in main (argc=3, argv=0x7fffffffd918) at main.c:732
Could you please check for those?
I will check it.
Thanks
Huang Shijie
6:34 a.m.
New subject: [PATCH 3/4] xarray: add large folio support
When we meet an large folio page cache node(height=1),
the real data layout looks like this:
--------------------------------------------
crash> p *(struct xa_node*)0xffff889883a6a910
$5 = {
shift = 0 '\000',
offset = 0 '\000',
count = 64 '@',
nr_values = 0 '\000',
.................
slots = { 0xffffea0061d21000, 0x2, 0x2, 0x2,
0xffffea0121d85c00, 0x12, 0x12, 0x12,
0xffffea0121d9f400, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
0xffffea0121583800, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42,
0xffffea0121833e00, 0x62, 0x62, 0x62, 0x62, 0x62, 0x62, 0x62,
0xffffea0121eb3800, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82
},
.................
}
--------------------------------------------
The page orders for above folios:
0xffffea0061d21000 --> order 2
0xffffea0121d85c00 --> order 2
0xffffea0121d9f400 --> order 3
0xffffea0121583800 --> order 3
0xffffea0121833e00 --> order 3
0xffffea0121eb3800 --> order 5
Current code does not work correctly with large folio page cache.
This patch adds the large folio support with following:
1.) changed the do_xarray_iter() to detect the order of a folio,
and skip the dummy slots for a large folio.
2.) updated do_xarray_count/do_xarray_dump/do_xarray_dump_cb
with correct page number if we meet a large folio.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
filesys.c | 10 ++++++----
tools.c | 10 +++++++---
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/filesys.c b/filesys.c
index 1e070a3..b6dab55 100644
--- a/filesys.c
+++ b/filesys.c
@@ -4222,7 +4222,7 @@ static void do_xarray_count(ulong node, ulong slot, const char
*path,
ulong index, void *private)
{
struct do_xarray_info *info = private;
- info->count++;
+ info->count += 1 << folio_order(slot);
}
static void do_xarray_search(ulong node, ulong slot, const char *path,
ulong index, void *private)
@@ -4239,8 +4239,10 @@ static void do_xarray_dump(ulong node, ulong slot, const char
*path,
ulong index, void *private)
{
struct do_xarray_info *info = private;
- fprintf(fp, "[%ld] %lx\n", index, slot);
- info->count++;
+ int order = folio_order(slot);
+
+ fprintf(fp, "[%ld] %lx, order:%d\n", index, slot, order);
+ info->count += 1 << order;
}
static void do_xarray_gather(ulong node, ulong slot, const char *path,
ulong index, void *private)
@@ -4274,7 +4276,7 @@ static void do_xarray_dump_cb(ulong node, ulong slot, const char
*path,
"operation failed: entry: %ld item: %lx\n",
info->count, slot);
}
- info->count++;
+ info->count += 1 << folio_order(slot);
}
/*
diff --git a/tools.c b/tools.c
index 69250c4..23fa91a 100644
--- a/tools.c
+++ b/tools.c
@@ -4737,15 +4737,17 @@ do_xarray_iter(ulong node, uint height, char *path,
ulong index, struct xarray_ops *ops)
{
uint off;
+ uint order;
if (!hq_enter(node))
error(FATAL,
"\nduplicate tree node: %lx\n", node);
- for (off = 0; off < XA_CHUNK_SIZE; off++) {
+ for (off = 0; off < XA_CHUNK_SIZE; off += 1 << order) {
ulong slot;
ulong shift = (height - 1) * XA_CHUNK_SHIFT;
+ order = 0;
readmem(node + OFFSET(xa_node_slots) +
sizeof(void *) * off, KVADDR, &slot, sizeof(void *),
"xa_node.slots[off]", FAULT_ON_ERROR);
@@ -4755,9 +4757,11 @@ do_xarray_iter(ulong node, uint height, char *path,
if ((slot & XARRAY_TAG_MASK) == XARRAY_TAG_INTERNAL)
slot &= ~XARRAY_TAG_INTERNAL;
- if (height == 1)
+ if (height == 1) {
ops->entry(node, slot, path, index | off, ops->private);
- else {
+ if (ops->type == XARRAY_TYPE_PAGE_CACHE)
+ order = folio_order(slot);
+ } else {
ulong child_index = index | (off << shift);
char child_path[BUFSIZE];
sprintf(child_path, "%s/%d", path, off);
--
2.43.0
6:34 a.m.
New subject: [PATCH 4/4] add "files -n" command for an inode
In the NUMA machine, it is useful to know the memory distribution of
an inode page cache:
How many pages in the node 0?
How many pages in the node 1?
Add "files -n" command to get the memory distribution information:
1.) Add new argument for dump_inode_page_cache_info()
2.) make page_to_nid() a global function.
3.) Add summary_inode_page() to check each page's node
information.
4.) Use print_inode_summary_info() to print the
memory distribution information of an inode.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
defs.h | 1 +
filesys.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
help.c | 24 +++++++++++++++++++++-
memory.c | 4 ++--
4 files changed, 81 insertions(+), 8 deletions(-)
diff --git a/defs.h b/defs.h
index fdea94f..dccb79f 100644
--- a/defs.h
+++ b/defs.h
@@ -5948,6 +5948,7 @@ int dump_inode_page(ulong);
ulong valid_section_nr(ulong);
void display_memory_from_file_offset(ulonglong, long, void *);
void swap_info_init(void);
+int page_to_nid(ulong);
/*
* filesys.c
diff --git a/filesys.c b/filesys.c
index b6dab55..ae75221 100644
--- a/filesys.c
+++ b/filesys.c
@@ -49,7 +49,7 @@ static int match_file_string(char *, char *, char *);
static ulong get_root_vfsmount(char *);
static void check_live_arch_mismatch(void);
static long get_inode_nrpages(ulong);
-static void dump_inode_page_cache_info(ulong);
+static void dump_inode_page_cache_info(ulong, void *callback);
#define DENTRY_CACHE (20)
#define INODE_CACHE (20)
@@ -2240,8 +2240,38 @@ get_inode_nrpages(ulong i_mapping)
return nrpages;
}
+/* Used to collect the numa information for an inode */
+static ulong *numa_node;
+
static void
-dump_inode_page_cache_info(ulong inode)
+print_inode_summary_info(void)
+{
+ int i;
+
+ fprintf(fp, " NODE PAGES\n");
+ for (i = 0; i < vt->numnodes; i++)
+ fprintf(fp, " %2d %8ld\n", i, numa_node[i]);
+}
+
+static int
+summary_inode_page(ulong page)
+{
+ int node;
+
+ if (!is_page_ptr(page, NULL))
+ error(FATAL, "Invalid inode page(0x%lx)\n", page);
+
+ node = page_to_nid(page);
+ if (node < 0 || node >= vt->numnodes)
+ error(FATAL, "Invalid node(%d) for page(0x%lx)\n", node, page);
+
+ numa_node[node] += 1 << folio_order(page);
+
+ return 1;
+}
+
+static void
+dump_inode_page_cache_info(ulong inode, void *callback)
{
char *inode_buf;
ulong i_mapping, nrpages, root_rnode, xarray, count;
@@ -2284,7 +2314,7 @@ dump_inode_page_cache_info(ulong inode)
root_rnode = i_mapping + OFFSET(address_space_page_tree);
lp.index = 0;
- lp.value = (void *)&dump_inode_page;
+ lp.value = callback;
if (root_rnode)
count = do_radix_tree(root_rnode, RADIX_TREE_DUMP_CB, &lp);
@@ -2324,7 +2354,7 @@ cmd_files(void)
ref = NULL;
refarg = NULL;
- while ((c = getopt(argcnt, args, "d:R:p:c")) != EOF) {
+ while ((c = getopt(argcnt, args, "d:n:R:p:c")) != EOF) {
switch(c)
{
case 'R':
@@ -2343,11 +2373,31 @@ cmd_files(void)
display_dentry_info(value);
return;
+ case 'n':
+ if (VALID_MEMBER(address_space_page_tree) &&
+ VALID_MEMBER(inode_i_mapping)) {
+ value = htol(optarg, FAULT_ON_ERROR, NULL);
+
+ /* Allocate the array for this inode */
+ numa_node = malloc(sizeof(ulong) * vt->numnodes);
+ BZERO(numa_node, sizeof(ulong) * vt->numnodes);
+
+ dump_inode_page_cache_info(value, (void
*)&summary_inode_page);
+
+ /* Print out the NUMA node information for this inode */
+ print_inode_summary_info();
+
+ free(numa_node);
+ numa_node = NULL;
+ } else
+ option_not_supported('n');
+ return;
+
case 'p':
if (VALID_MEMBER(address_space_page_tree) &&
VALID_MEMBER(inode_i_mapping)) {
value = htol(optarg, FAULT_ON_ERROR, NULL);
- dump_inode_page_cache_info(value);
+ dump_inode_page_cache_info(value, (void *)&dump_inode_page);
} else
option_not_supported('p');
return;
diff --git a/help.c b/help.c
index 91d1550..6f97289 100644
--- a/help.c
+++ b/help.c
@@ -7900,7 +7900,7 @@ NULL
char *help_files[] = {
"files",
"open files",
-"[-d dentry] | [-p inode] | [-c] [-R reference] [pid | taskp] ... ",
+"[-d dentry] | [-p inode] | [-n inode]|[-c] [-R reference] [pid | taskp] ...
",
" This command displays information about open files of a context.",
" It prints the context's current root directory and current working",
" directory, and then for each open file descriptor it prints a pointer",
@@ -7915,6 +7915,8 @@ char *help_files[] = {
" super block, file type, and full pathname.",
" -p inode given a hexadecimal inode address, dump all of its pages",
" that are in the page cache.",
+" -n inode given a hexadecimal inode address, check all the pages",
+" in the page cache, and display a NUMA node distribution.",
" -c for each open file descriptor, prints a pointer to its",
" inode, a pointer to the inode's i_mapping address_space",
" structure, the number of pages of the inode that are in",
@@ -8024,6 +8026,26 @@ char *help_files[] = {
" ca1ddde0 2eeef000 f59b91ac 3 2 82c
referenced,uptodate,lru,private",
" ca36b300 3b598000 f59b91ac 4 2 82c
referenced,uptodate,lru,private",
" ca202680 30134000 f59b91ac 5 2 82c
referenced,uptodate,lru,private",
+" ",
+" For the inode at address ffff8898857c55a8, display the NUMA node",
+" distribution of its pages that are in the page cache:",
+" %s> files -n ffff8898857c55a8",
+" INODE NRPAGES",
+" ffff8898857c55a8 51748",
+" ",
+" NODE PAGES",
+" 0 51536",
+" 1 0",
+" 2 0",
+" 3 0",
+" 4 0",
+" 5 212",
+" 6 0",
+" 7 0",
+" 8 0",
+" 9 0",
+" 10 0",
+" 11 0",
" ",
NULL
};
diff --git a/memory.c b/memory.c
index 9080332..73fd082 100644
--- a/memory.c
+++ b/memory.c
@@ -301,7 +301,7 @@ static int dump_vm_event_state(void);
static int dump_page_states(void);
static int generic_read_dumpfile(ulonglong, void *, long, char *, ulong);
static int generic_write_dumpfile(ulonglong, void *, long, char *, ulong);
-static int page_to_nid(ulong);
+int page_to_nid(ulong);
static int get_kmem_cache_list(ulong **);
static int get_kmem_cache_root_list(ulong **);
static int get_kmem_cache_child_list(ulong **, ulong);
@@ -20058,7 +20058,7 @@ is_kmem_cache_addr_common(ulong vaddr, char *kbuf)
/*
* Kernel-config-neutral page-to-node evaluator.
*/
-static int
+int
page_to_nid(ulong page)
{
int i;
--
2.43.0
43
days inactive
56
days old
devel@lists.crash-utility.osci.io
6 comments
2 participants
participants (2)
-
Huang Shijie -
Tao Liu