Hi tao,
[PATCH 1/2] [1/2]arm64: Fix "vtop" command to display swap information on
Linux 6.10 and later
Kernel commit 55564814a838 ("arm64/mm: Move PTE_PRESENT_INVALID
to overlay PTE_NG"), which is contained in Linux 6.10 and
later kernels, changed the format of swap entries on arm64.
Without the patch, the "vtop" command cannot display swap information
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Guanyou.Chen <[email protected]>
---
arm64.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/arm64.c b/arm64.c
index 1723595..c125655 100644
--- a/arm64.c
+++ b/arm64.c
@@ -712,7 +712,16 @@ arm64_init(int when)
}
}
- if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
+ if (THIS_KERNEL_VERSION >= LINUX(6,10,0)) {
+ ms->__SWP_TYPE_BITS = 5;
+ ms->__SWP_TYPE_SHIFT = 6;
+ ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
+ ms->__SWP_OFFSET_SHIFT = 12;
+ ms->__SWP_OFFSET_BITS = 50;
+ ms->__SWP_OFFSET_MASK = ((1UL << ms->__SWP_OFFSET_BITS) - 1);
+ ms->PTE_PROT_NONE = 0; /* unused */
+ ms->PTE_FILE = 0; /* unused */
+ } else if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
ms->__SWP_TYPE_BITS = 5;
ms->__SWP_TYPE_SHIFT = 3;
ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) - 1);
--
2.34.1
[PATCH 2/2] [2/2]arm64: Fix "vtop" command to display swap information on
Linux 6.10 and later
Kernel commit 798cb7f9aec3 ("swapon(2)/swapoff(2): don't bother with
block size") removed swap_info_struct.old_block_size member at Linux
6.10-rc1. The crash-utility has used this to determine whether a swap
is a partition or file and to determine the way to get the swap path.
before:
crash> vtop 2000000
VIRTUAL PHYSICAL
2000000 (not mapped)
PAGE DIRECTORY: ffffff8106356000
PGD: ffffff8106356000 => 800000186355003
PMD: ffffff8106355080 => 8000001476f5003
PTE: ffffff80c76f5000 => 101a62004
PTE OFFSET: 1055330
vtop: cannot determine swap location
after:
crash> vtop 2000000
VIRTUAL PHYSICAL
2000000 (not mapped)
PAGE DIRECTORY: ffffff8106356000
PGD: ffffff8106356000 => 800000186355003
PMD: ffffff8106355080 => 8000001476f5003
PTE: ffffff80c76f5000 => 101a62004
PTE SWAP OFFSET
101a62004 /first_stage_ramdisk/dev/block/zram0 1055330
VMA START END FLAGS FILE
ffffff81a06e8b00 2000000 22000000 100073
SWAP: /first_stage_ramdisk/dev/block/zram0 OFFSET: 1055330
Signed-off-by: Guanyou.Chen <[email protected]>
---
memory.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/memory.c b/memory.c
index 400d31a..cbc8d2f 100644
--- a/memory.c
+++ b/memory.c
@@ -16415,6 +16415,8 @@ get_swapdev(ulong type, char *buf)
ulong vfsmnt;
char *devname;
char buf1[BUFSIZE];
+ int swap_file_is_file =
+ STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"), "file");
swap_info_init();
@@ -16474,7 +16476,8 @@ get_swapdev(ulong type, char *buf)
vfsmnt = ULONG(vt->swap_info_struct +
OFFSET(swap_info_struct_swap_vfsmnt));
get_pathname(swap_file, buf, BUFSIZE, 1, vfsmnt);
- } else if (VALID_MEMBER (swap_info_struct_old_block_size))
{
+ } else if (VALID_MEMBER (swap_info_struct_old_block_size)
+ || swap_file_is_file) {
devname = vfsmount_devname(file_to_vfsmnt(swap_file),
buf1, BUFSIZE);
get_pathname(file_to_dentry(swap_file),
--
2.34.1
Thanks,
Guanyou
Tao Liu <[email protected]> 于2025年12月6日周六 03:24写道：
> Hi Guanyou,
>
> Just a reminder that please don't send the patches as the form of
> email attachments. Please send it via commands like: "git send-email
> --to=<...> HEAD~2", such that people can do inline commenting on your
> code.
>
> Other than that, the patch LGTM, so ack patch 1 & 2.
>
> Thanks,
> Tao Liu
>
> On Fri, Dec 5, 2025 at 7:02 PM Guanyou Chen <[email protected]>
> wrote:
> >
> > Hi Tao
> >
> > attached split 2 patches.
> >
> > Thanks
> > Guanyou
> >
> >
> > Tao Liu <[email protected]> 于2025年12月5日周五 11:31写道：
> >>
> >> Hi Guanyou,
> >>
> >> On Fri, Dec 5, 2025 at 3:03 PM Guanyou Chen <[email protected]>
> wrote:
> >> >
> >> > Hi Tao,
> >> >
> >> > Check swap_file_is_file from crash commit 3452fe802bf94
> >> > ("Fix "kmem -i" and "swap" commands on Linux 6.10-rc1 and later
> kernels")
> >> >
> >> > Thanks,
> >> > Guanyou
> >> >
> >> > Tao Liu <[email protected]> 于2025年12月5日周五 06:40写道：
> >> >>
> >> >> Hi Guanyou,
> >> >>
> >> >> On Thu, Dec 4, 2025 at 11:33 PM Guanyou Chen <
> [email protected]> wrote:
> >> >> >
> >> >> > Hi Lianbo
> >> >> >
> >> >> > Kernel commit 55564814a838 ("arm64/mm: Move PTE_PRESENT_INVALID
> >> >> > to overlay PTE_NG"), which is contained in Linux 6.10 and
> >> >> > later kernels, changed the format of swap entries on arm64.
> >> >> > Without the patch, the "vtop" command cannot display swap
> information
> >> >> >
> >> >> > before:
> >> >> > crash> vtop 2000000
> >> >> > VIRTUAL PHYSICAL
> >> >> > 2000000 (not mapped)
> >> >> >
> >> >> > PAGE DIRECTORY: ffffff8106356000
> >> >> > PGD: ffffff8106356000 => 800000186355003
> >> >> > PMD: ffffff8106355080 => 8000001476f5003
> >> >> > PTE: ffffff80c76f5000 => 101a62004
> >> >> >
> >> >> > PTE OFFSET: 1055330
> >> >> > vtop: cannot determine swap location
> >> >> >
> >> >> > without the patch:
> >> >> > crash> vtop 2000000
> >> >> > VIRTUAL PHYSICAL
> >> >> > 2000000 (not mapped)
> >> >> >
> >> >> > PAGE DIRECTORY: ffffff8106356000
> >> >> > PGD: ffffff8106356000 => 800000186355003
> >> >> > PMD: ffffff8106355080 => 8000001476f5003
> >> >> > PTE: ffffff80c76f5000 => 101a62004
> >> >> >
> >> >> > PTE SWAP OFFSET
> >> >> > 101a62004 /first_stage_ramdisk/dev/block/zram0 1055330
> >> >> >
> >> >> > VMA START END FLAGS FILE
> >> >> > ffffff81a06e8b00 2000000 22000000 100073
> >> >> >
> >> >> > SWAP: /first_stage_ramdisk/dev/block/zram0 OFFSET: 1055330
> >> >> >
> >> >> > Link:
> https://lore.kernel.org/r/[email protected]
> >> >> > Signed-off-by: Guanyou.Chen <[email protected]>
> >> >> > ---
> >> >> > arm64.c | 11 ++++++++++-
> >> >> > memory.c | 5 ++++-
> >> >> > 2 files changed, 14 insertions(+), 2 deletions(-)
> >> >> >
> >> >> > diff --git a/arm64.c b/arm64.c
> >> >> > index 1723595..c125655 100644
> >> >> > --- a/arm64.c
> >> >> > +++ b/arm64.c
> >> >> > @@ -712,7 +712,16 @@ arm64_init(int when)
> >> >> > }
> >> >> > }
> >> >> >
> >> >> > - if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
> >> >> > + if (THIS_KERNEL_VERSION >= LINUX(6,10,0)) {
> >> >> > + ms->__SWP_TYPE_BITS = 5;
> >> >> > + ms->__SWP_TYPE_SHIFT = 6;
> >> >> > + ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) -
> 1);
> >> >> > + ms->__SWP_OFFSET_SHIFT = 12;
> >> >> > + ms->__SWP_OFFSET_BITS = 50;
> >> >> > + ms->__SWP_OFFSET_MASK = ((1UL <<
> ms->__SWP_OFFSET_BITS) - 1);
> >> >> > + ms->PTE_PROT_NONE = 0; /* unused */
> >> >> > + ms->PTE_FILE = 0; /* unused */
> >> >> > + } else if (THIS_KERNEL_VERSION >= LINUX(5,19,0)) {
> >>
> >> Sorry maybe I didn't make myself clear. What I mean is, the kernel
> >> link, aka
> https://lore.kernel.org/r/[email protected],
> >> updated the information as you have addressed above, and this part is
> >> OK to me.
> >>
> >> >> > ms->__SWP_TYPE_BITS = 5;
> >> >> > ms->__SWP_TYPE_SHIFT = 3;
> >> >> > ms->__SWP_TYPE_MASK = ((1UL << ms->__SWP_TYPE_BITS) -
> 1);
> >> >> > diff --git a/memory.c b/memory.c
> >> >> > index 400d31a..cbc8d2f 100644
> >> >> > --- a/memory.c
> >> >> > +++ b/memory.c
> >> >> > @@ -16415,6 +16415,8 @@ get_swapdev(ulong type, char *buf)
> >> >> > ulong vfsmnt;
> >> >> > char *devname;
> >> >> > char buf1[BUFSIZE];
> >> >> > + int swap_file_is_file =
> >> >> > + STREQ(MEMBER_TYPE_NAME("swap_info_struct", "swap_file"),
> "file");
> >> >> >
> >> >> > swap_info_init();
> >> >> >
> >> >> > @@ -16474,7 +16476,8 @@ get_swapdev(ulong type, char *buf)
> >> >> > vfsmnt = ULONG(vt->swap_info_struct +
> >> >> > OFFSET(swap_info_struct_swap_vfsmnt));
> >> >> > get_pathname(swap_file, buf, BUFSIZE, 1, vfsmnt);
> >> >> > - } else if (VALID_MEMBER
> (swap_info_struct_old_block_size)) {
> >> >> > + } else if (VALID_MEMBER
> (swap_info_struct_old_block_size)
> >> >> > + || swap_file_is_file) {
> >>
> >> But the link nor your commit log doesn't provide information for the
> >> above swap_file_is_file code change. Like why do you need to add the
> >> "|| swap_file_is_file" check here? Does it have any relations with the
> >> previous __SWP_TYPE_XXX value updating? What I'm trying to figure out
> >> is whether your __SWP_TYPE_XXX updating and swap_file_is_file
> >> checking, are independent of each other and should go into 2 seperated
> >> patches.
> >>
> >> >>
> >> >> Any reason for the extra swap_file_is_file check? From the kernel
> >> >> patch link you posted, only the __SWP_TYPE_XXX changes, which is
> >> >> presented in (THIS_KERNEL_VERSION >= LINUX(6,10,0), but no info
> >> >> related to swap_file_is_file check?
> >> >>
> >> >> Thanks,
> >> >> Tao Liu
> >> >>
> >> >>
> >> >> > devname = vfsmount_devname(file_to_vfsmnt(swap_file),
> >> >> > buf1, BUFSIZE);
> >> >> > get_pathname(file_to_dentry(swap_file),
> >> >> > --
> >> >> > 2.34.1
> >> >> >
> >> >> > Thanks.
> >> >> > Guanyou
> >> >>
> >>
>
>
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