| Message ID | 20210401212445.3534721-1-slyfox@gentoo.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm: page_owner: fetch backtrace only for tracked pages | expand |
On 4/1/21 11:24 PM, Sergei Trofimovich wrote: > Very minor optimization. I'm not entirely sure about accuracy of "only for tracked pages". Missing page_ext is something I'm not even sure how possible it is in practice, probably just an error condition (failed to be allocated?). Or did you observe this in practice? But anyway, the change is not wrong. > CC: Andrew Morton <akpm@linux-foundation.org> > CC: linux-mm@kvack.org > Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> > --- > mm/page_owner.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/page_owner.c b/mm/page_owner.c > index 63e4ecaba97b..7147fd34a948 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -140,14 +140,14 @@ void __reset_page_owner(struct page *page, unsigned int order) > { > int i; > struct page_ext *page_ext; > - depot_stack_handle_t handle = 0; > + depot_stack_handle_t handle; > struct page_owner *page_owner; > > - handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); > - > page_ext = lookup_page_ext(page); > if (unlikely(!page_ext)) > return; > + > + handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); > for (i = 0; i < (1 << order); i++) { > __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); > page_owner = get_page_owner(page_ext); >
On Wed, Apr 07, 2021 at 05:49:14PM +0200, Vlastimil Babka wrote: > On 4/1/21 11:24 PM, Sergei Trofimovich wrote: > > Very minor optimization. > > I'm not entirely sure about accuracy of "only for tracked pages". Missing > page_ext is something I'm not even sure how possible it is in practice, probably > just an error condition (failed to be allocated?). Or did you observe this in > practice? But anyway, the change is not wrong. Never saw missing 'page_ext' in practice (I also did not check for it explicitly). I agree "optimization" is misleading. "cleanup" might be a better wording. > > CC: Andrew Morton <akpm@linux-foundation.org> > > CC: linux-mm@kvack.org > > Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> > > Acked-by: Vlastimil Babka <vbabka@suse.cz> > > > --- > > mm/page_owner.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/mm/page_owner.c b/mm/page_owner.c > > index 63e4ecaba97b..7147fd34a948 100644 > > --- a/mm/page_owner.c > > +++ b/mm/page_owner.c > > @@ -140,14 +140,14 @@ void __reset_page_owner(struct page *page, unsigned int order) > > { > > int i; > > struct page_ext *page_ext; > > - depot_stack_handle_t handle = 0; > > + depot_stack_handle_t handle; > > struct page_owner *page_owner; > > > > - handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); > > - > > page_ext = lookup_page_ext(page); > > if (unlikely(!page_ext)) > > return; > > + > > + handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); > > for (i = 0; i < (1 << order); i++) { > > __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); > > page_owner = get_page_owner(page_ext); > > >
diff --git a/mm/page_owner.c b/mm/page_owner.c index 63e4ecaba97b..7147fd34a948 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -140,14 +140,14 @@ void __reset_page_owner(struct page *page, unsigned int order) { int i; struct page_ext *page_ext; - depot_stack_handle_t handle = 0; + depot_stack_handle_t handle; struct page_owner *page_owner; - handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); - page_ext = lookup_page_ext(page); if (unlikely(!page_ext)) return; + + handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); for (i = 0; i < (1 << order); i++) { __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags); page_owner = get_page_owner(page_ext);
Very minor optimization. CC: Andrew Morton <akpm@linux-foundation.org> CC: linux-mm@kvack.org Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> --- mm/page_owner.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)