| Message ID | a37b13dd91bd3eadcd56a08cb3c839616f8457e7.1692440586.git.baolin.wang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Extend migrate_misplaced_page() to support batch migration | expand |
Baolin Wang <baolin.wang@linux.alibaba.com> writes: > Now there are 3 places will validate if a page can mirate or not, and > some validations are performed later, which will waste some CPU to call > numa_migrate_prep(). > > Thus we can move all the migration validation into numa_migrate_prep(), > which is more maintainable as well as saving some CPU resources. Another > benefit is that it can serve as a preparation for supporting batch migration > in do_numa_page() in future. > > Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> > --- > mm/memory.c | 19 +++++++++++++++++++ > mm/migrate.c | 19 ------------------- > 2 files changed, 19 insertions(+), 19 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index d003076b218d..bee9b1e86ef0 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4747,6 +4747,25 @@ int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, > *flags |= TNF_FAULT_LOCAL; > } > > + /* > + * Don't migrate file pages that are mapped in multiple processes > + * with execute permissions as they are probably shared libraries. > + */ > + if (page_mapcount(page) != 1 && page_is_file_lru(page) && > + (vma->vm_flags & VM_EXEC)) > + return NUMA_NO_NODE; > + > + /* > + * Also do not migrate dirty pages as not all filesystems can move > + * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. > + */ > + if (page_is_file_lru(page) && PageDirty(page)) > + return NUMA_NO_NODE; > + > + /* Do not migrate THP mapped by multiple processes */ > + if (PageTransHuge(page) && total_mapcount(page) > 1) > + return NUMA_NO_NODE; > + > return mpol_misplaced(page, vma, addr); In mpol_misplaced()->should_numa_migrate_memory(), accessing CPU and PID will be recorded. So the code change above will introduce some behavior change. How about move these checks into a separate function which is called between numa_migrate_prep() and migrate_misplaced_page() after unlocking PTL? -- Best Regards, Huang, Ying > } > > diff --git a/mm/migrate.c b/mm/migrate.c > index e21d5a7e7447..9cc98fb1d6ec 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2485,10 +2485,6 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) > > VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); > > - /* Do not migrate THP mapped by multiple processes */ > - if (PageTransHuge(page) && total_mapcount(page) > 1) > - return 0; > - > /* Avoid migrating to a node that is nearly full */ > if (!migrate_balanced_pgdat(pgdat, nr_pages)) { > int z; > @@ -2533,21 +2529,6 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, > LIST_HEAD(migratepages); > int nr_pages = thp_nr_pages(page); > > - /* > - * Don't migrate file pages that are mapped in multiple processes > - * with execute permissions as they are probably shared libraries. > - */ > - if (page_mapcount(page) != 1 && page_is_file_lru(page) && > - (vma->vm_flags & VM_EXEC)) > - goto out; > - > - /* > - * Also do not migrate dirty pages as not all filesystems can move > - * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. > - */ > - if (page_is_file_lru(page) && PageDirty(page)) > - goto out; > - > isolated = numamigrate_isolate_page(pgdat, page); > if (!isolated) > goto out;
On 8/21/2023 10:20 AM, Huang, Ying wrote: > Baolin Wang <baolin.wang@linux.alibaba.com> writes: > >> Now there are 3 places will validate if a page can mirate or not, and >> some validations are performed later, which will waste some CPU to call >> numa_migrate_prep(). >> >> Thus we can move all the migration validation into numa_migrate_prep(), >> which is more maintainable as well as saving some CPU resources. Another >> benefit is that it can serve as a preparation for supporting batch migration >> in do_numa_page() in future. >> >> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> >> --- >> mm/memory.c | 19 +++++++++++++++++++ >> mm/migrate.c | 19 ------------------- >> 2 files changed, 19 insertions(+), 19 deletions(-) >> >> diff --git a/mm/memory.c b/mm/memory.c >> index d003076b218d..bee9b1e86ef0 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -4747,6 +4747,25 @@ int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, >> *flags |= TNF_FAULT_LOCAL; >> } >> >> + /* >> + * Don't migrate file pages that are mapped in multiple processes >> + * with execute permissions as they are probably shared libraries. >> + */ >> + if (page_mapcount(page) != 1 && page_is_file_lru(page) && >> + (vma->vm_flags & VM_EXEC)) >> + return NUMA_NO_NODE; >> + >> + /* >> + * Also do not migrate dirty pages as not all filesystems can move >> + * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. >> + */ >> + if (page_is_file_lru(page) && PageDirty(page)) >> + return NUMA_NO_NODE; >> + >> + /* Do not migrate THP mapped by multiple processes */ >> + if (PageTransHuge(page) && total_mapcount(page) > 1) >> + return NUMA_NO_NODE; >> + >> return mpol_misplaced(page, vma, addr); > > In mpol_misplaced()->should_numa_migrate_memory(), accessing CPU and PID > will be recorded. So the code change above will introduce some behavior > change. Indeed. > > How about move these checks into a separate function which is called > between numa_migrate_prep() and migrate_misplaced_page() after unlocking > PTL? Sounds reasonable to me. Thanks for your input. > > -- > Best Regards, > Huang, Ying > >> } >> >> diff --git a/mm/migrate.c b/mm/migrate.c >> index e21d5a7e7447..9cc98fb1d6ec 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -2485,10 +2485,6 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) >> >> VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); >> >> - /* Do not migrate THP mapped by multiple processes */ >> - if (PageTransHuge(page) && total_mapcount(page) > 1) >> - return 0; >> - >> /* Avoid migrating to a node that is nearly full */ >> if (!migrate_balanced_pgdat(pgdat, nr_pages)) { >> int z; >> @@ -2533,21 +2529,6 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, >> LIST_HEAD(migratepages); >> int nr_pages = thp_nr_pages(page); >> >> - /* >> - * Don't migrate file pages that are mapped in multiple processes >> - * with execute permissions as they are probably shared libraries. >> - */ >> - if (page_mapcount(page) != 1 && page_is_file_lru(page) && >> - (vma->vm_flags & VM_EXEC)) >> - goto out; >> - >> - /* >> - * Also do not migrate dirty pages as not all filesystems can move >> - * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. >> - */ >> - if (page_is_file_lru(page) && PageDirty(page)) >> - goto out; >> - >> isolated = numamigrate_isolate_page(pgdat, page); >> if (!isolated) >> goto out;
diff --git a/mm/memory.c b/mm/memory.c index d003076b218d..bee9b1e86ef0 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4747,6 +4747,25 @@ int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, *flags |= TNF_FAULT_LOCAL; } + /* + * Don't migrate file pages that are mapped in multiple processes + * with execute permissions as they are probably shared libraries. + */ + if (page_mapcount(page) != 1 && page_is_file_lru(page) && + (vma->vm_flags & VM_EXEC)) + return NUMA_NO_NODE; + + /* + * Also do not migrate dirty pages as not all filesystems can move + * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. + */ + if (page_is_file_lru(page) && PageDirty(page)) + return NUMA_NO_NODE; + + /* Do not migrate THP mapped by multiple processes */ + if (PageTransHuge(page) && total_mapcount(page) > 1) + return NUMA_NO_NODE; + return mpol_misplaced(page, vma, addr); } diff --git a/mm/migrate.c b/mm/migrate.c index e21d5a7e7447..9cc98fb1d6ec 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2485,10 +2485,6 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) VM_BUG_ON_PAGE(order && !PageTransHuge(page), page); - /* Do not migrate THP mapped by multiple processes */ - if (PageTransHuge(page) && total_mapcount(page) > 1) - return 0; - /* Avoid migrating to a node that is nearly full */ if (!migrate_balanced_pgdat(pgdat, nr_pages)) { int z; @@ -2533,21 +2529,6 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, LIST_HEAD(migratepages); int nr_pages = thp_nr_pages(page); - /* - * Don't migrate file pages that are mapped in multiple processes - * with execute permissions as they are probably shared libraries. - */ - if (page_mapcount(page) != 1 && page_is_file_lru(page) && - (vma->vm_flags & VM_EXEC)) - goto out; - - /* - * Also do not migrate dirty pages as not all filesystems can move - * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. - */ - if (page_is_file_lru(page) && PageDirty(page)) - goto out; - isolated = numamigrate_isolate_page(pgdat, page); if (!isolated) goto out;
Now there are 3 places will validate if a page can mirate or not, and some validations are performed later, which will waste some CPU to call numa_migrate_prep(). Thus we can move all the migration validation into numa_migrate_prep(), which is more maintainable as well as saving some CPU resources. Another benefit is that it can serve as a preparation for supporting batch migration in do_numa_page() in future. Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> --- mm/memory.c | 19 +++++++++++++++++++ mm/migrate.c | 19 ------------------- 2 files changed, 19 insertions(+), 19 deletions(-)