| Message ID | 20230113154253.92480-1-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] mm/page_ext: Do not allocate space for page_ext->flags if not needed | expand |
On Fri, Jan 13, 2023 at 03:42:53PM +0000, Pasha Tatashin wrote: > There is 8 byte page_ext->flags field allocated per page whenever > CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext > uses flags. Therefore, check whether flags is needed at least by one > user and if so allocate space for it. > > For example when page_table_check is enabled, on a machine with 128G > of memory before the fix: > > [ 2.244288] allocated 536870912 bytes of page_ext > after the fix: > [ 2.160154] allocated 268435456 bytes of page_ext > > Also, add a comment before page_ext_operations that describes the > field, and remove check if need() is set, as that is now a required Nit: fields > field. > > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > --- > include/linux/page_ext.h | 19 +++++++++++++++++++ > mm/page_ext.c | 14 ++++++++++++-- > mm/page_owner.c | 1 + > mm/page_table_check.c | 1 + > 4 files changed, 33 insertions(+), 2 deletions(-) > > Changelog: > v2: Fixed field name in page_owner.c that caused build error. > v3: Added comment before page_ext_operations, removed check if > need is null. > > diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h > index 22be4582faae..be0b465c7d78 100644 > --- a/include/linux/page_ext.h > +++ b/include/linux/page_ext.h > @@ -7,15 +7,31 @@ > #include <linux/stackdepot.h> > > struct pglist_data; > + > +/* Please make it kerneldoc. > + * Each Page Extension client must define page_ext_operations in > + * page_ext_ops array. > + * offset offset to the client's data within page_ext. Offset is returned to > + * the client by page_ext_init. > + * size the size of the client data within page_ext. > + * need() function that returns true if client requires page_ext > + * init() (optional) called to initialize client once page_exts are allocated. > + * using_shared_ext_flags true when client is using shared page_ext->flags > + * field. > + */ > struct page_ext_operations { > size_t offset; > size_t size; > bool (*need)(void); > void (*init)(void); > + bool using_shared_ext_flags; I'd s/using_shared_ext_flags/need_shared_flags. > }; > > #ifdef CONFIG_PAGE_EXTENSION > > +/* > + * The page_ext_flags users must set using_shared_ext_flags to true. > + */ > enum page_ext_flags { > PAGE_EXT_OWNER, > PAGE_EXT_OWNER_ALLOCATED, > @@ -31,6 +47,9 @@ enum page_ext_flags { > * page_ext helps us add more information about the page. > * All page_ext are allocated at boot or memory hotplug event, > * then the page_ext for pfn always exists. > + * Note: that if none of the users of page_ext is setting I'd drop that ^that > + * using_shared_ext_flags to true, the field cannot be used, > + * as it will be overlapped with another data. > */ > struct page_ext { > unsigned long flags; > diff --git a/mm/page_ext.c b/mm/page_ext.c > index 4ee522fd381c..d14dbd44fa49 100644 > --- a/mm/page_ext.c > +++ b/mm/page_ext.c > @@ -71,6 +71,7 @@ static bool need_page_idle(void) > } > static struct page_ext_operations page_idle_ops __initdata = { > .need = need_page_idle, > + .using_shared_ext_flags = true, > }; > #endif > > @@ -86,7 +87,7 @@ static struct page_ext_operations *page_ext_ops[] __initdata = { > #endif > }; > > -unsigned long page_ext_size = sizeof(struct page_ext); > +unsigned long page_ext_size; > > static unsigned long total_usage; > static struct page_ext *lookup_page_ext(const struct page *page); > @@ -106,7 +107,16 @@ static bool __init invoke_need_callbacks(void) > bool need = false; > > for (i = 0; i < entries; i++) { > - if (page_ext_ops[i]->need && page_ext_ops[i]->need()) { > + if (page_ext_ops[i]->need()) { > + if (page_ext_ops[i]->using_shared_ext_flags) { > + page_ext_size = sizeof(struct page_ext); > + break; > + } > + } > + } > + > + for (i = 0; i < entries; i++) { > + if (page_ext_ops[i]->need()) { > page_ext_ops[i]->offset = page_ext_size; > page_ext_size += page_ext_ops[i]->size; > need = true; > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 2d27f532df4c..1a62ab3fc00e 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -99,6 +99,7 @@ struct page_ext_operations page_owner_ops = { > .size = sizeof(struct page_owner), > .need = need_page_owner, > .init = init_page_owner, > + .using_shared_ext_flags = true, > }; > > static inline struct page_owner *get_page_owner(struct page_ext *page_ext) > diff --git a/mm/page_table_check.c b/mm/page_table_check.c > index 93e633c1d587..74cfe89d5f53 100644 > --- a/mm/page_table_check.c > +++ b/mm/page_table_check.c > @@ -45,6 +45,7 @@ struct page_ext_operations page_table_check_ops = { > .size = sizeof(struct page_table_check), > .need = need_page_table_check, > .init = init_page_table_check, > + .using_shared_ext_flags = false, > }; > > static struct page_table_check *get_page_table_check(struct page_ext *page_ext) > -- > 2.39.0.314.g84b9a713c41-goog > >
On 1/13/23 16:42, Pasha Tatashin wrote: > There is 8 byte page_ext->flags field allocated per page whenever > CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext > uses flags. Therefore, check whether flags is needed at least by one > user and if so allocate space for it. > > For example when page_table_check is enabled, on a machine with 128G > of memory before the fix: > > [ 2.244288] allocated 536870912 bytes of page_ext > after the fix: > [ 2.160154] allocated 268435456 bytes of page_ext > > Also, add a comment before page_ext_operations that describes the > field, and remove check if need() is set, as that is now a required > field. > > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Mike's comments look reasonable to me. > --- > include/linux/page_ext.h | 19 +++++++++++++++++++ > mm/page_ext.c | 14 ++++++++++++-- > mm/page_owner.c | 1 + > mm/page_table_check.c | 1 + > 4 files changed, 33 insertions(+), 2 deletions(-) > > Changelog: > v2: Fixed field name in page_owner.c that caused build error. > v3: Added comment before page_ext_operations, removed check if > need is null. > > diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h > index 22be4582faae..be0b465c7d78 100644 > --- a/include/linux/page_ext.h > +++ b/include/linux/page_ext.h > @@ -7,15 +7,31 @@ > #include <linux/stackdepot.h> > > struct pglist_data; > + > +/* > + * Each Page Extension client must define page_ext_operations in > + * page_ext_ops array. > + * offset offset to the client's data within page_ext. Offset is returned to > + * the client by page_ext_init. > + * size the size of the client data within page_ext. > + * need() function that returns true if client requires page_ext > + * init() (optional) called to initialize client once page_exts are allocated. > + * using_shared_ext_flags true when client is using shared page_ext->flags > + * field. > + */ > struct page_ext_operations { > size_t offset; > size_t size; > bool (*need)(void); > void (*init)(void); > + bool using_shared_ext_flags; > }; > > #ifdef CONFIG_PAGE_EXTENSION > > +/* > + * The page_ext_flags users must set using_shared_ext_flags to true. > + */ > enum page_ext_flags { > PAGE_EXT_OWNER, > PAGE_EXT_OWNER_ALLOCATED, > @@ -31,6 +47,9 @@ enum page_ext_flags { > * page_ext helps us add more information about the page. > * All page_ext are allocated at boot or memory hotplug event, > * then the page_ext for pfn always exists. > + * Note: that if none of the users of page_ext is setting > + * using_shared_ext_flags to true, the field cannot be used, > + * as it will be overlapped with another data. > */ > struct page_ext { > unsigned long flags; > diff --git a/mm/page_ext.c b/mm/page_ext.c > index 4ee522fd381c..d14dbd44fa49 100644 > --- a/mm/page_ext.c > +++ b/mm/page_ext.c > @@ -71,6 +71,7 @@ static bool need_page_idle(void) > } > static struct page_ext_operations page_idle_ops __initdata = { > .need = need_page_idle, > + .using_shared_ext_flags = true, > }; > #endif > > @@ -86,7 +87,7 @@ static struct page_ext_operations *page_ext_ops[] __initdata = { > #endif > }; > > -unsigned long page_ext_size = sizeof(struct page_ext); > +unsigned long page_ext_size; > > static unsigned long total_usage; > static struct page_ext *lookup_page_ext(const struct page *page); > @@ -106,7 +107,16 @@ static bool __init invoke_need_callbacks(void) > bool need = false; > > for (i = 0; i < entries; i++) { > - if (page_ext_ops[i]->need && page_ext_ops[i]->need()) { > + if (page_ext_ops[i]->need()) { > + if (page_ext_ops[i]->using_shared_ext_flags) { > + page_ext_size = sizeof(struct page_ext); > + break; > + } > + } > + } > + > + for (i = 0; i < entries; i++) { > + if (page_ext_ops[i]->need()) { > page_ext_ops[i]->offset = page_ext_size; > page_ext_size += page_ext_ops[i]->size; > need = true; > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 2d27f532df4c..1a62ab3fc00e 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -99,6 +99,7 @@ struct page_ext_operations page_owner_ops = { > .size = sizeof(struct page_owner), > .need = need_page_owner, > .init = init_page_owner, > + .using_shared_ext_flags = true, > }; > > static inline struct page_owner *get_page_owner(struct page_ext *page_ext) > diff --git a/mm/page_table_check.c b/mm/page_table_check.c > index 93e633c1d587..74cfe89d5f53 100644 > --- a/mm/page_table_check.c > +++ b/mm/page_table_check.c > @@ -45,6 +45,7 @@ struct page_ext_operations page_table_check_ops = { > .size = sizeof(struct page_table_check), > .need = need_page_table_check, > .init = init_page_table_check, > + .using_shared_ext_flags = false, > }; > > static struct page_table_check *get_page_table_check(struct page_ext *page_ext)
On 16.01.23 11:51, Vlastimil Babka wrote: > On 1/13/23 16:42, Pasha Tatashin wrote: >> There is 8 byte page_ext->flags field allocated per page whenever >> CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext >> uses flags. Therefore, check whether flags is needed at least by one >> user and if so allocate space for it. >> >> For example when page_table_check is enabled, on a machine with 128G >> of memory before the fix: >> >> [ 2.244288] allocated 536870912 bytes of page_ext >> after the fix: >> [ 2.160154] allocated 268435456 bytes of page_ext >> >> Also, add a comment before page_ext_operations that describes the >> field, and remove check if need() is set, as that is now a required >> field. >> >> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > > Acked-by: Vlastimil Babka <vbabka@suse.cz> > > Mike's comments look reasonable to me. Seconded Acked-by: David Hildenbrand <david@redhat.com>
Hey Mike, > > Also, add a comment before page_ext_operations that describes the > > field, and remove check if need() is set, as that is now a required > > Nit: fields OK > > struct pglist_data; > > + > > +/* > > Please make it kerneldoc. OK > > void (*init)(void); > > + bool using_shared_ext_flags; > > I'd s/using_shared_ext_flags/need_shared_flags. Sure > > + * Note: that if none of the users of page_ext is setting > > I'd drop that ^that OK Thanks for the review, I will send a new version soon. Pasha
> >> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > > > > Acked-by: Vlastimil Babka <vbabka@suse.cz> > > > > Mike's comments look reasonable to me. > > Seconded > > Acked-by: David Hildenbrand <david@redhat.com> Thank you Vlastimil and David. Pasha > > -- > Thanks, > > David / dhildenb >
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h index 22be4582faae..be0b465c7d78 100644 --- a/include/linux/page_ext.h +++ b/include/linux/page_ext.h @@ -7,15 +7,31 @@ #include <linux/stackdepot.h> struct pglist_data; + +/* + * Each Page Extension client must define page_ext_operations in + * page_ext_ops array. + * offset offset to the client's data within page_ext. Offset is returned to + * the client by page_ext_init. + * size the size of the client data within page_ext. + * need() function that returns true if client requires page_ext + * init() (optional) called to initialize client once page_exts are allocated. + * using_shared_ext_flags true when client is using shared page_ext->flags + * field. + */ struct page_ext_operations { size_t offset; size_t size; bool (*need)(void); void (*init)(void); + bool using_shared_ext_flags; }; #ifdef CONFIG_PAGE_EXTENSION +/* + * The page_ext_flags users must set using_shared_ext_flags to true. + */ enum page_ext_flags { PAGE_EXT_OWNER, PAGE_EXT_OWNER_ALLOCATED, @@ -31,6 +47,9 @@ enum page_ext_flags { * page_ext helps us add more information about the page. * All page_ext are allocated at boot or memory hotplug event, * then the page_ext for pfn always exists. + * Note: that if none of the users of page_ext is setting + * using_shared_ext_flags to true, the field cannot be used, + * as it will be overlapped with another data. */ struct page_ext { unsigned long flags; diff --git a/mm/page_ext.c b/mm/page_ext.c index 4ee522fd381c..d14dbd44fa49 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -71,6 +71,7 @@ static bool need_page_idle(void) } static struct page_ext_operations page_idle_ops __initdata = { .need = need_page_idle, + .using_shared_ext_flags = true, }; #endif @@ -86,7 +87,7 @@ static struct page_ext_operations *page_ext_ops[] __initdata = { #endif }; -unsigned long page_ext_size = sizeof(struct page_ext); +unsigned long page_ext_size; static unsigned long total_usage; static struct page_ext *lookup_page_ext(const struct page *page); @@ -106,7 +107,16 @@ static bool __init invoke_need_callbacks(void) bool need = false; for (i = 0; i < entries; i++) { - if (page_ext_ops[i]->need && page_ext_ops[i]->need()) { + if (page_ext_ops[i]->need()) { + if (page_ext_ops[i]->using_shared_ext_flags) { + page_ext_size = sizeof(struct page_ext); + break; + } + } + } + + for (i = 0; i < entries; i++) { + if (page_ext_ops[i]->need()) { page_ext_ops[i]->offset = page_ext_size; page_ext_size += page_ext_ops[i]->size; need = true; diff --git a/mm/page_owner.c b/mm/page_owner.c index 2d27f532df4c..1a62ab3fc00e 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -99,6 +99,7 @@ struct page_ext_operations page_owner_ops = { .size = sizeof(struct page_owner), .need = need_page_owner, .init = init_page_owner, + .using_shared_ext_flags = true, }; static inline struct page_owner *get_page_owner(struct page_ext *page_ext) diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 93e633c1d587..74cfe89d5f53 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -45,6 +45,7 @@ struct page_ext_operations page_table_check_ops = { .size = sizeof(struct page_table_check), .need = need_page_table_check, .init = init_page_table_check, + .using_shared_ext_flags = false, }; static struct page_table_check *get_page_table_check(struct page_ext *page_ext)
There is 8 byte page_ext->flags field allocated per page whenever CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext uses flags. Therefore, check whether flags is needed at least by one user and if so allocate space for it. For example when page_table_check is enabled, on a machine with 128G of memory before the fix: [ 2.244288] allocated 536870912 bytes of page_ext after the fix: [ 2.160154] allocated 268435456 bytes of page_ext Also, add a comment before page_ext_operations that describes the field, and remove check if need() is set, as that is now a required field. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> --- include/linux/page_ext.h | 19 +++++++++++++++++++ mm/page_ext.c | 14 ++++++++++++-- mm/page_owner.c | 1 + mm/page_table_check.c | 1 + 4 files changed, 33 insertions(+), 2 deletions(-) Changelog: v2: Fixed field name in page_owner.c that caused build error. v3: Added comment before page_ext_operations, removed check if need is null.