* [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
@ 2016-06-17 9:41 Vitaly Kuznetsov
2016-06-21 5:43 ` Atsushi Kumagai
0 siblings, 1 reply; 7+ messages in thread
From: Vitaly Kuznetsov @ 2016-06-17 9:41 UTC (permalink / raw)
To: kexec; +Cc: Masaki Tachibana, Atsushi Kumagai, Minoru Usui, David Anderson
_count member was renamed to _refcount in linux commit 0139aa7b7fa12
("mm: rename _count, field of the struct page, to _refcount") and this
broke makedumpfile. The reason for making the change was to find all users
accessing it directly and not through the recommended API. I tried
suggesting to revert the change but failed, I see no other choice than to
start supporting both _count and _refcount in makedumpfile.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
Changes since 'v1':
- Make '_refcount' the default [Atsushi Kumagai]
---
makedumpfile.c | 26 +++++++++++++++++++++-----
makedumpfile.h | 3 ++-
2 files changed, 23 insertions(+), 6 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index 853b999..fd884d3 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -1579,7 +1579,14 @@ get_structure_info(void)
*/
SIZE_INIT(page, "page");
OFFSET_INIT(page.flags, "page", "flags");
- OFFSET_INIT(page._count, "page", "_count");
+ OFFSET_INIT(page._refcount, "page", "_refcount");
+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
+ info->flag_use_count = TRUE;
+ OFFSET_INIT(page._refcount, "page", "_count");
+ } else {
+ info->flag_use_count = FALSE;
+ }
+
OFFSET_INIT(page.mapping, "page", "mapping");
OFFSET_INIT(page._mapcount, "page", "_mapcount");
OFFSET_INIT(page.private, "page", "private");
@@ -2044,7 +2051,7 @@ get_mem_type(void)
if ((SIZE(page) == NOT_FOUND_STRUCTURE)
|| (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
- || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
+ || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
|| (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
ret = NOT_FOUND_MEMTYPE;
} else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
* write the member offset of 1st kernel
*/
WRITE_MEMBER_OFFSET("page.flags", page.flags);
- WRITE_MEMBER_OFFSET("page._count", page._count);
+ if (info->flag_use_count)
+ WRITE_MEMBER_OFFSET("page._count", page._refcount);
+ else
+ WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
WRITE_MEMBER_OFFSET("page.lru", page.lru);
WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
READ_MEMBER_OFFSET("page.flags", page.flags);
- READ_MEMBER_OFFSET("page._count", page._count);
+ READ_MEMBER_OFFSET("page._refcount", page._refcount);
+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
+ info->flag_use_count = TRUE;
+ READ_MEMBER_OFFSET("page._count", page._refcount);
+ } else {
+ info->flag_use_count = FALSE;
+ }
READ_MEMBER_OFFSET("page.mapping", page.mapping);
READ_MEMBER_OFFSET("page.lru", page.lru);
READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
pcache = page_cache + (index_pg * SIZE(page));
flags = ULONG(pcache + OFFSET(page.flags));
- _count = UINT(pcache + OFFSET(page._count));
+ _count = UINT(pcache + OFFSET(page._refcount));
mapping = ULONG(pcache + OFFSET(page.mapping));
if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
diff --git a/makedumpfile.h b/makedumpfile.h
index 251d4bf..533e5b8 100644
--- a/makedumpfile.h
+++ b/makedumpfile.h
@@ -1100,6 +1100,7 @@ struct DumpInfo {
int flag_nospace; /* the flag of "No space on device" error */
int flag_vmemmap; /* kernel supports vmemmap address space */
int flag_excludevm; /* -e - excluding unused vmemmap pages */
+ int flag_use_count; /* _refcount is named _count in struct page */
unsigned long vaddr_for_vtop; /* virtual address for debugging */
long page_size; /* size of page */
long page_shift;
@@ -1483,7 +1484,7 @@ struct size_table {
struct offset_table {
struct page {
long flags;
- long _count;
+ long _refcount;
long mapping;
long lru;
long _mapcount;
--
2.5.5
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^ permalink raw reply related [flat|nested] 7+ messages in thread* RE: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-17 9:41 [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page Vitaly Kuznetsov
@ 2016-06-21 5:43 ` Atsushi Kumagai
2016-06-21 6:45 ` Pratyush Anand
0 siblings, 1 reply; 7+ messages in thread
From: Atsushi Kumagai @ 2016-06-21 5:43 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: Masaki Tachibana, Minoru Usui, kexec@lists.infradead.org,
David Anderson
Hello Vitaly,
>_count member was renamed to _refcount in linux commit 0139aa7b7fa12
>("mm: rename _count, field of the struct page, to _refcount") and this
>broke makedumpfile. The reason for making the change was to find all users
>accessing it directly and not through the recommended API. I tried
>suggesting to revert the change but failed, I see no other choice than to
>start supporting both _count and _refcount in makedumpfile.
>
>Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>---
>Changes since 'v1':
>- Make '_refcount' the default [Atsushi Kumagai]
Good fix, I'll merge this into v1.6.1.
Thanks,
Atsushi Kumagai
>---
> makedumpfile.c | 26 +++++++++++++++++++++-----
> makedumpfile.h | 3 ++-
> 2 files changed, 23 insertions(+), 6 deletions(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index 853b999..fd884d3 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -1579,7 +1579,14 @@ get_structure_info(void)
> */
> SIZE_INIT(page, "page");
> OFFSET_INIT(page.flags, "page", "flags");
>- OFFSET_INIT(page._count, "page", "_count");
>+ OFFSET_INIT(page._refcount, "page", "_refcount");
>+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>+ info->flag_use_count = TRUE;
>+ OFFSET_INIT(page._refcount, "page", "_count");
>+ } else {
>+ info->flag_use_count = FALSE;
>+ }
>+
> OFFSET_INIT(page.mapping, "page", "mapping");
> OFFSET_INIT(page._mapcount, "page", "_mapcount");
> OFFSET_INIT(page.private, "page", "private");
>@@ -2044,7 +2051,7 @@ get_mem_type(void)
>
> if ((SIZE(page) == NOT_FOUND_STRUCTURE)
> || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
>- || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
>+ || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
> || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
> ret = NOT_FOUND_MEMTYPE;
> } else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
>@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
> * write the member offset of 1st kernel
> */
> WRITE_MEMBER_OFFSET("page.flags", page.flags);
>- WRITE_MEMBER_OFFSET("page._count", page._count);
>+ if (info->flag_use_count)
>+ WRITE_MEMBER_OFFSET("page._count", page._refcount);
>+ else
>+ WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
> WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
> WRITE_MEMBER_OFFSET("page.lru", page.lru);
> WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
>@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
>
>
> READ_MEMBER_OFFSET("page.flags", page.flags);
>- READ_MEMBER_OFFSET("page._count", page._count);
>+ READ_MEMBER_OFFSET("page._refcount", page._refcount);
>+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>+ info->flag_use_count = TRUE;
>+ READ_MEMBER_OFFSET("page._count", page._refcount);
>+ } else {
>+ info->flag_use_count = FALSE;
>+ }
> READ_MEMBER_OFFSET("page.mapping", page.mapping);
> READ_MEMBER_OFFSET("page.lru", page.lru);
> READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
>@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> pcache = page_cache + (index_pg * SIZE(page));
>
> flags = ULONG(pcache + OFFSET(page.flags));
>- _count = UINT(pcache + OFFSET(page._count));
>+ _count = UINT(pcache + OFFSET(page._refcount));
> mapping = ULONG(pcache + OFFSET(page.mapping));
>
> if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 251d4bf..533e5b8 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -1100,6 +1100,7 @@ struct DumpInfo {
> int flag_nospace; /* the flag of "No space on device" error */
> int flag_vmemmap; /* kernel supports vmemmap address space */
> int flag_excludevm; /* -e - excluding unused vmemmap pages */
>+ int flag_use_count; /* _refcount is named _count in struct page */
> unsigned long vaddr_for_vtop; /* virtual address for debugging */
> long page_size; /* size of page */
> long page_shift;
>@@ -1483,7 +1484,7 @@ struct size_table {
> struct offset_table {
> struct page {
> long flags;
>- long _count;
>+ long _refcount;
> long mapping;
> long lru;
> long _mapcount;
>--
>2.5.5
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-21 5:43 ` Atsushi Kumagai
@ 2016-06-21 6:45 ` Pratyush Anand
2016-06-21 8:05 ` Vitaly Kuznetsov
0 siblings, 1 reply; 7+ messages in thread
From: Pratyush Anand @ 2016-06-21 6:45 UTC (permalink / raw)
To: Atsushi Kumagai
Cc: Masaki Tachibana, Vitaly Kuznetsov, Minoru Usui,
kexec@lists.infradead.org, David Anderson
On 21/06/2016:05:43:29 AM, Atsushi Kumagai wrote:
> Hello Vitaly,
>
> >_count member was renamed to _refcount in linux commit 0139aa7b7fa12
> >("mm: rename _count, field of the struct page, to _refcount") and this
> >broke makedumpfile. The reason for making the change was to find all users
> >accessing it directly and not through the recommended API. I tried
> >suggesting to revert the change but failed, I see no other choice than to
> >start supporting both _count and _refcount in makedumpfile.
> >
> >Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> >---
> >Changes since 'v1':
> >- Make '_refcount' the default [Atsushi Kumagai]
Sorry, I missed this conversation earlier.
>
> Good fix, I'll merge this into v1.6.1.
>
> Thanks,
> Atsushi Kumagai
>
> >---
> > makedumpfile.c | 26 +++++++++++++++++++++-----
> > makedumpfile.h | 3 ++-
> > 2 files changed, 23 insertions(+), 6 deletions(-)
> >
> >diff --git a/makedumpfile.c b/makedumpfile.c
> >index 853b999..fd884d3 100644
> >--- a/makedumpfile.c
> >+++ b/makedumpfile.c
> >@@ -1579,7 +1579,14 @@ get_structure_info(void)
> > */
> > SIZE_INIT(page, "page");
> > OFFSET_INIT(page.flags, "page", "flags");
> >- OFFSET_INIT(page._count, "page", "_count");
> >+ OFFSET_INIT(page._refcount, "page", "_refcount");
> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
> >+ info->flag_use_count = TRUE;
> >+ OFFSET_INIT(page._refcount, "page", "_count");
> >+ } else {
> >+ info->flag_use_count = FALSE;
Probably we could have avoided this flag and could have solved it same way as we
have solved for other such kernel changes, like that of "module.module_core".
Infact, we do not need to add "_refcount" in makedumpfile's page struct.
See:
https://github.com/pratyushanand/makedumpfile/commit/8c58c177d27d4ac31db2ee42442ef056dbbd2c93
~Pratyush
> >+ }
> >+
> > OFFSET_INIT(page.mapping, "page", "mapping");
> > OFFSET_INIT(page._mapcount, "page", "_mapcount");
> > OFFSET_INIT(page.private, "page", "private");
> >@@ -2044,7 +2051,7 @@ get_mem_type(void)
> >
> > if ((SIZE(page) == NOT_FOUND_STRUCTURE)
> > || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
> >- || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
> >+ || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
> > || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
> > ret = NOT_FOUND_MEMTYPE;
> > } else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
> >@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
> > * write the member offset of 1st kernel
> > */
> > WRITE_MEMBER_OFFSET("page.flags", page.flags);
> >- WRITE_MEMBER_OFFSET("page._count", page._count);
> >+ if (info->flag_use_count)
> >+ WRITE_MEMBER_OFFSET("page._count", page._refcount);
> >+ else
> >+ WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
> > WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
> > WRITE_MEMBER_OFFSET("page.lru", page.lru);
> > WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
> >@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
> >
> >
> > READ_MEMBER_OFFSET("page.flags", page.flags);
> >- READ_MEMBER_OFFSET("page._count", page._count);
> >+ READ_MEMBER_OFFSET("page._refcount", page._refcount);
> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
> >+ info->flag_use_count = TRUE;
> >+ READ_MEMBER_OFFSET("page._count", page._refcount);
> >+ } else {
> >+ info->flag_use_count = FALSE;
> >+ }
> > READ_MEMBER_OFFSET("page.mapping", page.mapping);
> > READ_MEMBER_OFFSET("page.lru", page.lru);
> > READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
> >@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> > pcache = page_cache + (index_pg * SIZE(page));
> >
> > flags = ULONG(pcache + OFFSET(page.flags));
> >- _count = UINT(pcache + OFFSET(page._count));
> >+ _count = UINT(pcache + OFFSET(page._refcount));
> > mapping = ULONG(pcache + OFFSET(page.mapping));
> >
> > if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
> >diff --git a/makedumpfile.h b/makedumpfile.h
> >index 251d4bf..533e5b8 100644
> >--- a/makedumpfile.h
> >+++ b/makedumpfile.h
> >@@ -1100,6 +1100,7 @@ struct DumpInfo {
> > int flag_nospace; /* the flag of "No space on device" error */
> > int flag_vmemmap; /* kernel supports vmemmap address space */
> > int flag_excludevm; /* -e - excluding unused vmemmap pages */
> >+ int flag_use_count; /* _refcount is named _count in struct page */
> > unsigned long vaddr_for_vtop; /* virtual address for debugging */
> > long page_size; /* size of page */
> > long page_shift;
> >@@ -1483,7 +1484,7 @@ struct size_table {
> > struct offset_table {
> > struct page {
> > long flags;
> >- long _count;
> >+ long _refcount;
> > long mapping;
> > long lru;
> > long _mapcount;
> >--
> >2.5.5
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
_______________________________________________
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-21 6:45 ` Pratyush Anand
@ 2016-06-21 8:05 ` Vitaly Kuznetsov
2016-06-21 10:03 ` Pratyush Anand
0 siblings, 1 reply; 7+ messages in thread
From: Vitaly Kuznetsov @ 2016-06-21 8:05 UTC (permalink / raw)
To: Pratyush Anand
Cc: Masaki Tachibana, Atsushi Kumagai, Minoru Usui,
kexec@lists.infradead.org, David Anderson
Pratyush Anand <panand@redhat.com> writes:
> On 21/06/2016:05:43:29 AM, Atsushi Kumagai wrote:
>> Hello Vitaly,
>>
>> >_count member was renamed to _refcount in linux commit 0139aa7b7fa12
>> >("mm: rename _count, field of the struct page, to _refcount") and this
>> >broke makedumpfile. The reason for making the change was to find all users
>> >accessing it directly and not through the recommended API. I tried
>> >suggesting to revert the change but failed, I see no other choice than to
>> >start supporting both _count and _refcount in makedumpfile.
>> >
>> >Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> >---
>> >Changes since 'v1':
>> >- Make '_refcount' the default [Atsushi Kumagai]
>
> Sorry, I missed this conversation earlier.
>
>>
>> Good fix, I'll merge this into v1.6.1.
>>
>> Thanks,
>> Atsushi Kumagai
>>
>> >---
>> > makedumpfile.c | 26 +++++++++++++++++++++-----
>> > makedumpfile.h | 3 ++-
>> > 2 files changed, 23 insertions(+), 6 deletions(-)
>> >
>> >diff --git a/makedumpfile.c b/makedumpfile.c
>> >index 853b999..fd884d3 100644
>> >--- a/makedumpfile.c
>> >+++ b/makedumpfile.c
>> >@@ -1579,7 +1579,14 @@ get_structure_info(void)
>> > */
>> > SIZE_INIT(page, "page");
>> > OFFSET_INIT(page.flags, "page", "flags");
>> >- OFFSET_INIT(page._count, "page", "_count");
>> >+ OFFSET_INIT(page._refcount, "page", "_refcount");
>> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>> >+ info->flag_use_count = TRUE;
>> >+ OFFSET_INIT(page._refcount, "page", "_count");
>> >+ } else {
>> >+ info->flag_use_count = FALSE;
>
> Probably we could have avoided this flag and could have solved it same way as we
> have solved for other such kernel changes, like that of "module.module_core".
> Infact, we do not need to add "_refcount" in makedumpfile's page struct.
>
Yes, the flag is only needed to do the write. Why do you think we don't
need it?
> See:
> https://github.com/pratyushanand/makedumpfile/commit/8c58c177d27d4ac31db2ee42442ef056dbbd2c93
>
> ~Pratyush
>
>> >+ }
>> >+
>> > OFFSET_INIT(page.mapping, "page", "mapping");
>> > OFFSET_INIT(page._mapcount, "page", "_mapcount");
>> > OFFSET_INIT(page.private, "page", "private");
>> >@@ -2044,7 +2051,7 @@ get_mem_type(void)
>> >
>> > if ((SIZE(page) == NOT_FOUND_STRUCTURE)
>> > || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
>> >- || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
>> >+ || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
>> > || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
>> > ret = NOT_FOUND_MEMTYPE;
>> > } else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
>> >@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
>> > * write the member offset of 1st kernel
>> > */
>> > WRITE_MEMBER_OFFSET("page.flags", page.flags);
>> >- WRITE_MEMBER_OFFSET("page._count", page._count);
>> >+ if (info->flag_use_count)
>> >+ WRITE_MEMBER_OFFSET("page._count", page._refcount);
>> >+ else
>> >+ WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
>> > WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
>> > WRITE_MEMBER_OFFSET("page.lru", page.lru);
>> > WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
>> >@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
>> >
>> >
>> > READ_MEMBER_OFFSET("page.flags", page.flags);
>> >- READ_MEMBER_OFFSET("page._count", page._count);
>> >+ READ_MEMBER_OFFSET("page._refcount", page._refcount);
>> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>> >+ info->flag_use_count = TRUE;
>> >+ READ_MEMBER_OFFSET("page._count", page._refcount);
>> >+ } else {
>> >+ info->flag_use_count = FALSE;
>> >+ }
>> > READ_MEMBER_OFFSET("page.mapping", page.mapping);
>> > READ_MEMBER_OFFSET("page.lru", page.lru);
>> > READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
>> >@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
>> > pcache = page_cache + (index_pg * SIZE(page));
>> >
>> > flags = ULONG(pcache + OFFSET(page.flags));
>> >- _count = UINT(pcache + OFFSET(page._count));
>> >+ _count = UINT(pcache + OFFSET(page._refcount));
>> > mapping = ULONG(pcache + OFFSET(page.mapping));
>> >
>> > if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
>> >diff --git a/makedumpfile.h b/makedumpfile.h
>> >index 251d4bf..533e5b8 100644
>> >--- a/makedumpfile.h
>> >+++ b/makedumpfile.h
>> >@@ -1100,6 +1100,7 @@ struct DumpInfo {
>> > int flag_nospace; /* the flag of "No space on device" error */
>> > int flag_vmemmap; /* kernel supports vmemmap address space */
>> > int flag_excludevm; /* -e - excluding unused vmemmap pages */
>> >+ int flag_use_count; /* _refcount is named _count in struct page */
>> > unsigned long vaddr_for_vtop; /* virtual address for debugging */
>> > long page_size; /* size of page */
>> > long page_shift;
>> >@@ -1483,7 +1484,7 @@ struct size_table {
>> > struct offset_table {
>> > struct page {
>> > long flags;
>> >- long _count;
>> >+ long _refcount;
>> > long mapping;
>> > long lru;
>> > long _mapcount;
>> >--
>> >2.5.5
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
--
Vitaly
_______________________________________________
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-21 8:05 ` Vitaly Kuznetsov
@ 2016-06-21 10:03 ` Pratyush Anand
2016-06-21 10:36 ` Vitaly Kuznetsov
0 siblings, 1 reply; 7+ messages in thread
From: Pratyush Anand @ 2016-06-21 10:03 UTC (permalink / raw)
To: Vitaly Kuznetsov
Cc: Masaki Tachibana, Atsushi Kumagai, Minoru Usui,
kexec@lists.infradead.org, David Anderson
On 21/06/2016:10:05:42 AM, Vitaly Kuznetsov wrote:
> Pratyush Anand <panand@redhat.com> writes:
>
> > On 21/06/2016:05:43:29 AM, Atsushi Kumagai wrote:
> >> Hello Vitaly,
> >>
> >> >_count member was renamed to _refcount in linux commit 0139aa7b7fa12
> >> >("mm: rename _count, field of the struct page, to _refcount") and this
> >> >broke makedumpfile. The reason for making the change was to find all users
> >> >accessing it directly and not through the recommended API. I tried
> >> >suggesting to revert the change but failed, I see no other choice than to
> >> >start supporting both _count and _refcount in makedumpfile.
> >> >
> >> >Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> >> >---
> >> >Changes since 'v1':
> >> >- Make '_refcount' the default [Atsushi Kumagai]
> >
> > Sorry, I missed this conversation earlier.
> >
> >>
> >> Good fix, I'll merge this into v1.6.1.
> >>
> >> Thanks,
> >> Atsushi Kumagai
> >>
> >> >---
> >> > makedumpfile.c | 26 +++++++++++++++++++++-----
> >> > makedumpfile.h | 3 ++-
> >> > 2 files changed, 23 insertions(+), 6 deletions(-)
> >> >
> >> >diff --git a/makedumpfile.c b/makedumpfile.c
> >> >index 853b999..fd884d3 100644
> >> >--- a/makedumpfile.c
> >> >+++ b/makedumpfile.c
> >> >@@ -1579,7 +1579,14 @@ get_structure_info(void)
> >> > */
> >> > SIZE_INIT(page, "page");
> >> > OFFSET_INIT(page.flags, "page", "flags");
> >> >- OFFSET_INIT(page._count, "page", "_count");
> >> >+ OFFSET_INIT(page._refcount, "page", "_refcount");
> >> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
> >> >+ info->flag_use_count = TRUE;
> >> >+ OFFSET_INIT(page._refcount, "page", "_count");
> >> >+ } else {
> >> >+ info->flag_use_count = FALSE;
> >
> > Probably we could have avoided this flag and could have solved it same way as we
> > have solved for other such kernel changes, like that of "module.module_core".
> > Infact, we do not need to add "_refcount" in makedumpfile's page struct.
> >
>
> Yes, the flag is only needed to do the write. Why do you think we don't
> need it?
IMHO, even if we write with "page._count", we would be able to get correct
value in next read, because we prefer reading with "page._count" over
"page._refcount". I think "crash utility" also gives priority for reading with
_count, so things should work without any issue.
~Pratyush
>
> > See:
> > https://github.com/pratyushanand/makedumpfile/commit/8c58c177d27d4ac31db2ee42442ef056dbbd2c93
> >
> > ~Pratyush
> >
> >> >+ }
> >> >+
> >> > OFFSET_INIT(page.mapping, "page", "mapping");
> >> > OFFSET_INIT(page._mapcount, "page", "_mapcount");
> >> > OFFSET_INIT(page.private, "page", "private");
> >> >@@ -2044,7 +2051,7 @@ get_mem_type(void)
> >> >
> >> > if ((SIZE(page) == NOT_FOUND_STRUCTURE)
> >> > || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
> >> >- || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
> >> >+ || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
> >> > || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
> >> > ret = NOT_FOUND_MEMTYPE;
> >> > } else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
> >> >@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
> >> > * write the member offset of 1st kernel
> >> > */
> >> > WRITE_MEMBER_OFFSET("page.flags", page.flags);
> >> >- WRITE_MEMBER_OFFSET("page._count", page._count);
> >> >+ if (info->flag_use_count)
> >> >+ WRITE_MEMBER_OFFSET("page._count", page._refcount);
> >> >+ else
> >> >+ WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
> >> > WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
> >> > WRITE_MEMBER_OFFSET("page.lru", page.lru);
> >> > WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
> >> >@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
> >> >
> >> >
> >> > READ_MEMBER_OFFSET("page.flags", page.flags);
> >> >- READ_MEMBER_OFFSET("page._count", page._count);
> >> >+ READ_MEMBER_OFFSET("page._refcount", page._refcount);
> >> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
> >> >+ info->flag_use_count = TRUE;
> >> >+ READ_MEMBER_OFFSET("page._count", page._refcount);
> >> >+ } else {
> >> >+ info->flag_use_count = FALSE;
> >> >+ }
> >> > READ_MEMBER_OFFSET("page.mapping", page.mapping);
> >> > READ_MEMBER_OFFSET("page.lru", page.lru);
> >> > READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
> >> >@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
> >> > pcache = page_cache + (index_pg * SIZE(page));
> >> >
> >> > flags = ULONG(pcache + OFFSET(page.flags));
> >> >- _count = UINT(pcache + OFFSET(page._count));
> >> >+ _count = UINT(pcache + OFFSET(page._refcount));
> >> > mapping = ULONG(pcache + OFFSET(page.mapping));
> >> >
> >> > if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
> >> >diff --git a/makedumpfile.h b/makedumpfile.h
> >> >index 251d4bf..533e5b8 100644
> >> >--- a/makedumpfile.h
> >> >+++ b/makedumpfile.h
> >> >@@ -1100,6 +1100,7 @@ struct DumpInfo {
> >> > int flag_nospace; /* the flag of "No space on device" error */
> >> > int flag_vmemmap; /* kernel supports vmemmap address space */
> >> > int flag_excludevm; /* -e - excluding unused vmemmap pages */
> >> >+ int flag_use_count; /* _refcount is named _count in struct page */
> >> > unsigned long vaddr_for_vtop; /* virtual address for debugging */
> >> > long page_size; /* size of page */
> >> > long page_shift;
> >> >@@ -1483,7 +1484,7 @@ struct size_table {
> >> > struct offset_table {
> >> > struct page {
> >> > long flags;
> >> >- long _count;
> >> >+ long _refcount;
> >> > long mapping;
> >> > long lru;
> >> > long _mapcount;
> >> >--
> >> >2.5.5
> >>
> >>
> >> _______________________________________________
> >> kexec mailing list
> >> kexec@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/kexec
>
> --
> Vitaly
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^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-21 10:03 ` Pratyush Anand
@ 2016-06-21 10:36 ` Vitaly Kuznetsov
2016-06-22 0:15 ` Atsushi Kumagai
0 siblings, 1 reply; 7+ messages in thread
From: Vitaly Kuznetsov @ 2016-06-21 10:36 UTC (permalink / raw)
To: Pratyush Anand
Cc: Masaki Tachibana, Atsushi Kumagai, Minoru Usui,
kexec@lists.infradead.org, David Anderson
Pratyush Anand <panand@redhat.com> writes:
> On 21/06/2016:10:05:42 AM, Vitaly Kuznetsov wrote:
>> Pratyush Anand <panand@redhat.com> writes:
>>
>> > On 21/06/2016:05:43:29 AM, Atsushi Kumagai wrote:
>> >> Hello Vitaly,
>> >>
>> >> >_count member was renamed to _refcount in linux commit 0139aa7b7fa12
>> >> >("mm: rename _count, field of the struct page, to _refcount") and this
>> >> >broke makedumpfile. The reason for making the change was to find all users
>> >> >accessing it directly and not through the recommended API. I tried
>> >> >suggesting to revert the change but failed, I see no other choice than to
>> >> >start supporting both _count and _refcount in makedumpfile.
>> >> >
>> >> >Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>> >> >---
>> >> >Changes since 'v1':
>> >> >- Make '_refcount' the default [Atsushi Kumagai]
>> >
>> > Sorry, I missed this conversation earlier.
>> >
>> >>
>> >> Good fix, I'll merge this into v1.6.1.
>> >>
>> >> Thanks,
>> >> Atsushi Kumagai
>> >>
>> >> >---
>> >> > makedumpfile.c | 26 +++++++++++++++++++++-----
>> >> > makedumpfile.h | 3 ++-
>> >> > 2 files changed, 23 insertions(+), 6 deletions(-)
>> >> >
>> >> >diff --git a/makedumpfile.c b/makedumpfile.c
>> >> >index 853b999..fd884d3 100644
>> >> >--- a/makedumpfile.c
>> >> >+++ b/makedumpfile.c
>> >> >@@ -1579,7 +1579,14 @@ get_structure_info(void)
>> >> > */
>> >> > SIZE_INIT(page, "page");
>> >> > OFFSET_INIT(page.flags, "page", "flags");
>> >> >- OFFSET_INIT(page._count, "page", "_count");
>> >> >+ OFFSET_INIT(page._refcount, "page", "_refcount");
>> >> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>> >> >+ info->flag_use_count = TRUE;
>> >> >+ OFFSET_INIT(page._refcount, "page", "_count");
>> >> >+ } else {
>> >> >+ info->flag_use_count = FALSE;
>> >
>> > Probably we could have avoided this flag and could have solved it same way as we
>> > have solved for other such kernel changes, like that of "module.module_core".
>> > Infact, we do not need to add "_refcount" in makedumpfile's page struct.
>> >
>>
>> Yes, the flag is only needed to do the write. Why do you think we don't
>> need it?
>
> IMHO, even if we write with "page._count", we would be able to get correct
> value in next read, because we prefer reading with "page._count" over
> "page._refcount". I think "crash utility" also gives priority for reading with
> _count, so things should work without any issue.
While things will probably work now while everyone still remembers the
old "_count" name it may happen that some tool will drop this support in
future and this will lead to an awkward situation when everythin works
with /proc/vmcore but doesn't work with makedumpfile's output. Said that
I think it makes sense for makedumpfile to be precise and write what we
read. IMO, of course, I'm not a regular makedumpfile contributor.
<skip>
--
Vitaly
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^ permalink raw reply [flat|nested] 7+ messages in thread* RE: [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page
2016-06-21 10:36 ` Vitaly Kuznetsov
@ 2016-06-22 0:15 ` Atsushi Kumagai
0 siblings, 0 replies; 7+ messages in thread
From: Atsushi Kumagai @ 2016-06-22 0:15 UTC (permalink / raw)
To: Vitaly Kuznetsov, Pratyush Anand
Cc: Masaki Tachibana, Minoru Usui, kexec@lists.infradead.org,
David Anderson
>Pratyush Anand <panand@redhat.com> writes:
>
>> On 21/06/2016:10:05:42 AM, Vitaly Kuznetsov wrote:
>>> Pratyush Anand <panand@redhat.com> writes:
>>>
>>> > On 21/06/2016:05:43:29 AM, Atsushi Kumagai wrote:
>>> >> Hello Vitaly,
>>> >>
>>> >> >_count member was renamed to _refcount in linux commit 0139aa7b7fa12
>>> >> >("mm: rename _count, field of the struct page, to _refcount") and this
>>> >> >broke makedumpfile. The reason for making the change was to find all users
>>> >> >accessing it directly and not through the recommended API. I tried
>>> >> >suggesting to revert the change but failed, I see no other choice than to
>>> >> >start supporting both _count and _refcount in makedumpfile.
>>> >> >
>>> >> >Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
>>> >> >---
>>> >> >Changes since 'v1':
>>> >> >- Make '_refcount' the default [Atsushi Kumagai]
>>> >
>>> > Sorry, I missed this conversation earlier.
>>> >
>>> >>
>>> >> Good fix, I'll merge this into v1.6.1.
>>> >>
>>> >> Thanks,
>>> >> Atsushi Kumagai
>>> >>
>>> >> >---
>>> >> > makedumpfile.c | 26 +++++++++++++++++++++-----
>>> >> > makedumpfile.h | 3 ++-
>>> >> > 2 files changed, 23 insertions(+), 6 deletions(-)
>>> >> >
>>> >> >diff --git a/makedumpfile.c b/makedumpfile.c
>>> >> >index 853b999..fd884d3 100644
>>> >> >--- a/makedumpfile.c
>>> >> >+++ b/makedumpfile.c
>>> >> >@@ -1579,7 +1579,14 @@ get_structure_info(void)
>>> >> > */
>>> >> > SIZE_INIT(page, "page");
>>> >> > OFFSET_INIT(page.flags, "page", "flags");
>>> >> >- OFFSET_INIT(page._count, "page", "_count");
>>> >> >+ OFFSET_INIT(page._refcount, "page", "_refcount");
>>> >> >+ if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>>> >> >+ info->flag_use_count = TRUE;
>>> >> >+ OFFSET_INIT(page._refcount, "page", "_count");
>>> >> >+ } else {
>>> >> >+ info->flag_use_count = FALSE;
>>> >
>>> > Probably we could have avoided this flag and could have solved it same way as we
>>> > have solved for other such kernel changes, like that of "module.module_core".
>>> > Infact, we do not need to add "_refcount" in makedumpfile's page struct.
>>> >
>>>
>>> Yes, the flag is only needed to do the write. Why do you think we don't
>>> need it?
>>
>> IMHO, even if we write with "page._count", we would be able to get correct
>> value in next read, because we prefer reading with "page._count" over
>> "page._refcount". I think "crash utility" also gives priority for reading with
>> _count, so things should work without any issue.
>
>While things will probably work now while everyone still remembers the
>old "_count" name it may happen that some tool will drop this support in
>future and this will lead to an awkward situation when everythin works
>with /proc/vmcore but doesn't work with makedumpfile's output. Said that
>I think it makes sense for makedumpfile to be precise and write what we
>read. IMO, of course, I'm not a regular makedumpfile contributor.
Yeah, I think it would be better to write down the correct current name
even if the code gets a bit more complicated, thus I accepted the Vitaly's patch.
Thanks,
Atsushi Kumagai
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-06-22 0:17 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2016-06-17 9:41 [PATCH v2] makedumpfile: support _count -> _refcount rename in struct page Vitaly Kuznetsov
2016-06-21 5:43 ` Atsushi Kumagai
2016-06-21 6:45 ` Pratyush Anand
2016-06-21 8:05 ` Vitaly Kuznetsov
2016-06-21 10:03 ` Pratyush Anand
2016-06-21 10:36 ` Vitaly Kuznetsov
2016-06-22 0:15 ` Atsushi Kumagai
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