On Sun, 21 Mar 2021 21:25:01 +0000 Sergei Trofimovich <sly...@gentoo.org> wrote:
> On some architectures (like ia64) stack walking is slow > and currently requires memory allocation. This causes stack > collection for page_owner=on to fall into recursion. > > This patch implements a page_owner_stack=off to allow page stats > collection. More user friendly alternative would be to have a GFP_ flag similar to __GFP_NOLOCKDEP which would allow us to skip the recursion. I'll prepare alternative patch. > Signed-off-by: Sergei Trofimovich <sly...@gentoo.org> > --- > .../admin-guide/kernel-parameters.txt | 6 +++++ > mm/Kconfig.debug | 3 ++- > mm/page_owner.c | 23 +++++++++++++------ > 3 files changed, 24 insertions(+), 8 deletions(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt > b/Documentation/admin-guide/kernel-parameters.txt > index 04545725f187..3e710c4ab4df 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -3518,6 +3518,12 @@ > we can turn it on. > on: enable the feature > > + page_owner_stack= [KNL] Boot-time parameter option disabling stack > + collection of page allocation. Has effect only if > + "page_owner=on" is set. Useful for cases when stack > + collection is too slow or not feasible. > + off: disable the feature > + > page_poison= [KNL] Boot-time parameter changing the state of > poisoning on the buddy allocator, available with > CONFIG_PAGE_POISONING=y. > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 1e73717802f8..c1ecaf066c93 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -57,7 +57,8 @@ config PAGE_OWNER > help to find bare alloc_page(s) leaks. Even if you include this > feature on your build, it is disabled in default. You should pass > "page_owner=on" to boot parameter in order to enable it. Eats > - a fair amount of memory if enabled. See tools/vm/page_owner_sort.c > + a fair amount of memory if enabled. Call chain tracking can be > + disabled with "page_owner_stack=off". See tools/vm/page_owner_sort.c > for user-space helper. > > If unsure, say N. > diff --git a/mm/page_owner.c b/mm/page_owner.c > index d15c7c4994f5..2cc1113fa28d 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -31,6 +31,7 @@ struct page_owner { > }; > > static bool page_owner_enabled = false; > +static bool page_owner_stack_enabled = true; > DEFINE_STATIC_KEY_FALSE(page_owner_inited); > > static depot_stack_handle_t dummy_handle; > @@ -41,21 +42,26 @@ static void init_early_allocated_pages(void); > > static int __init early_page_owner_param(char *buf) > { > - if (!buf) > - return -EINVAL; > - > - if (strcmp(buf, "on") == 0) > - page_owner_enabled = true; > - > - return 0; > + return kstrtobool(buf, &page_owner_enabled); > } > early_param("page_owner", early_page_owner_param); > > +static int __init early_page_owner_stack_param(char *buf) > +{ > + return kstrtobool(buf, &page_owner_stack_enabled); > +} > +early_param("page_owner_stack", early_page_owner_stack_param); > + > static bool need_page_owner(void) > { > return page_owner_enabled; > } > > +static bool need_page_owner_stack(void) > +{ > + return page_owner_stack_enabled; > +} > + > static __always_inline depot_stack_handle_t create_dummy_stack(void) > { > unsigned long entries[4]; > @@ -122,6 +128,9 @@ static noinline depot_stack_handle_t save_stack(gfp_t > flags) > depot_stack_handle_t handle; > unsigned int nr_entries; > > + if (!need_page_owner_stack()) > + return failure_handle; > + > nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); > > /* > -- > 2.31.0 > -- Sergei