On Thu 02-11-17 20:35:19, [email protected] wrote: > From: zhouxianrong <[email protected]> > > the purpose of this patch is that when a reading swap fault > happens on a clean swap cache page whose swap count is equal > to one, then try_to_free_swap could remove this page from > swap cache and mark this page dirty. so if later we reclaimed > this page then we could pageout this page due to this dirty. > so i want to allow this action only for writing swap fault. > > i sampled the data of non-dirty anonymous pages which is no > need to pageout and total anonymous pages in shrink_page_list. > > the results are: > > non-dirty anonymous pages total anonymous pages > before 26343 635218 > after 36907 634312
This data is absolutely pointless without describing the workload. You patch also stil fails to explain which workloads are going to benefit/suffer from the change and why it is a good thing to do in general. > Signed-off-by: zhouxianrong <[email protected]> > --- > mm/memory.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memory.c b/mm/memory.c > index a728bed..5a944fe 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -2999,7 +2999,7 @@ int do_swap_page(struct vm_fault *vmf) > } > > swap_free(entry); > - if (mem_cgroup_swap_full(page) || > + if (((vmf->flags & FAULT_FLAG_WRITE) && mem_cgroup_swap_full(page)) || > (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) > try_to_free_swap(page); > unlock_page(page); > -- > 1.7.9.5 > -- Michal Hocko SUSE Labs
