| Message ID | 20230919230909.530174-4-gregory.price@memverge.com |
|---|---|
| State | New, archived |
| Headers | show |
| Series | move_phys_pages syscall | expand |
On Tue, 19 Sep 2023 19:09:06 -0400 Gregory Price <gourry.memverge@gmail.com> wrote: > add_page_for_migration presently does two actions: > 1) validates the page is present and migratable > 2) isolates the page from LRU and puts it into the migration list > > Break add_page_for_migration into 2 functions: > add_page_for_migration - isolate the page from LUR and add to list > add_virt_page_for_migration - validate the page and call the above > > add_page_for_migration does not require the mm_struct and so can be > re-used for a physical addressing version of move_pages > > Signed-off-by: Gregory Price <gregory.price@memverge.com> A few things inline. > --- > mm/migrate.c | 83 +++++++++++++++++++++++++++++++--------------------- > 1 file changed, 50 insertions(+), 33 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index dbe436163d65..1123d841a7f1 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2042,52 +2042,33 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) > } > > /* > - * Resolves the given address to a struct page, isolates it from the LRU and > - * puts it to the given pagelist. > + * Isolates the page from the LRU and puts it into the given pagelist > * Returns: > * errno - if the page cannot be found/isolated Is found still meaningful for what is in here? > * 0 - when it doesn't have to be migrated because it is already on the > * target node > * 1 - when it has been queued > */ > -static int add_page_for_migration(struct mm_struct *mm, const void __user *p, > - int node, struct list_head *pagelist, bool migrate_all) > +static int add_page_for_migration(struct page *page, int node, > + struct list_head *pagelist, bool migrate_all) > { > - struct vm_area_struct *vma; > - unsigned long addr; > - struct page *page; > int err; > bool isolated; > > - mmap_read_lock(mm); > - addr = (unsigned long)untagged_addr_remote(mm, p); > - > - err = -EFAULT; > - vma = vma_lookup(mm, addr); > - if (!vma || !vma_migratable(vma)) > - goto out; > - > - /* FOLL_DUMP to ignore special (like zero) pages */ > - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); > - > - err = PTR_ERR(page); > - if (IS_ERR(page)) > - goto out; > - > err = -ENOENT; > if (!page) > goto out; As noted below - this check is now duplicated. Might make sense of course, but not obvious if it was intended. > > if (is_zone_device_page(page)) > - goto out_putpage; > + goto out; > > err = 0; > if (page_to_nid(page) == node) > - goto out_putpage; > + goto out; > > err = -EACCES; > if (page_mapcount(page) > 1 && !migrate_all) > - goto out_putpage; > + goto out; > > if (PageHuge(page)) { > if (PageHead(page)) { > @@ -2101,7 +2082,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, > isolated = isolate_lru_page(head); > if (!isolated) { > err = -EBUSY; > - goto out_putpage; > + goto out; > } > > err = 1; > @@ -2110,12 +2091,48 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, > NR_ISOLATED_ANON + page_is_file_lru(head), > thp_nr_pages(head)); > } > -out_putpage: > - /* > - * Either remove the duplicate refcount from > - * isolate_lru_page() or drop the page ref if it was > - * not isolated. > - */ > +out: Given nothing to do here now, perhaps remove to early returns as that may simplify some error paths. > + return err; > +} > + > +/* > + * Resolves the given address to a struct page, isolates it from the LRU and > + * puts it to the given pagelist. > + * Returns: > + * errno - if the page cannot be found/isolated > + * 0 - when it doesn't have to be migrated because it is already on the > + * target node > + * 1 - when it has been queued > + */ > +static int add_virt_page_for_migration(struct mm_struct *mm, > + const void __user *p, int node, struct list_head *pagelist, > + bool migrate_all) > +{ > + struct vm_area_struct *vma; > + unsigned long addr; > + struct page *page; > + int err = -EFAULT; > + > + mmap_read_lock(mm); > + addr = (unsigned long)untagged_addr_remote(mm, p); > + > + vma = vma_lookup(mm, addr); > + if (!vma || !vma_migratable(vma)) > + goto out; > + > + /* FOLL_DUMP to ignore special (like zero) pages */ > + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); > + > + err = PTR_ERR(page); > + if (IS_ERR(page)) > + goto out; > + > + err = -ENOENT; > + if (!page) > + goto out; You do this here then again in add_page_for_migration(). Does it need to be in both places? > + > + err = add_page_for_migration(page, node, pagelist, migrate_all); > + > put_page(page); > out: > mmap_read_unlock(mm); > @@ -2211,7 +2228,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > * Errors in the page lookup or isolation are not fatal and we simply > * report them via status > */ > - err = add_page_for_migration(mm, p, current_node, &pagelist, > + err = add_virt_page_for_migration(mm, p, current_node, &pagelist, > flags & MPOL_MF_MOVE_ALL); > > if (err > 0) {
diff --git a/mm/migrate.c b/mm/migrate.c index dbe436163d65..1123d841a7f1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2042,52 +2042,33 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) } /* - * Resolves the given address to a struct page, isolates it from the LRU and - * puts it to the given pagelist. + * Isolates the page from the LRU and puts it into the given pagelist * Returns: * errno - if the page cannot be found/isolated * 0 - when it doesn't have to be migrated because it is already on the * target node * 1 - when it has been queued */ -static int add_page_for_migration(struct mm_struct *mm, const void __user *p, - int node, struct list_head *pagelist, bool migrate_all) +static int add_page_for_migration(struct page *page, int node, + struct list_head *pagelist, bool migrate_all) { - struct vm_area_struct *vma; - unsigned long addr; - struct page *page; int err; bool isolated; - mmap_read_lock(mm); - addr = (unsigned long)untagged_addr_remote(mm, p); - - err = -EFAULT; - vma = vma_lookup(mm, addr); - if (!vma || !vma_migratable(vma)) - goto out; - - /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); - - err = PTR_ERR(page); - if (IS_ERR(page)) - goto out; - err = -ENOENT; if (!page) goto out; if (is_zone_device_page(page)) - goto out_putpage; + goto out; err = 0; if (page_to_nid(page) == node) - goto out_putpage; + goto out; err = -EACCES; if (page_mapcount(page) > 1 && !migrate_all) - goto out_putpage; + goto out; if (PageHuge(page)) { if (PageHead(page)) { @@ -2101,7 +2082,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, isolated = isolate_lru_page(head); if (!isolated) { err = -EBUSY; - goto out_putpage; + goto out; } err = 1; @@ -2110,12 +2091,48 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, NR_ISOLATED_ANON + page_is_file_lru(head), thp_nr_pages(head)); } -out_putpage: - /* - * Either remove the duplicate refcount from - * isolate_lru_page() or drop the page ref if it was - * not isolated. - */ +out: + return err; +} + +/* + * Resolves the given address to a struct page, isolates it from the LRU and + * puts it to the given pagelist. + * Returns: + * errno - if the page cannot be found/isolated + * 0 - when it doesn't have to be migrated because it is already on the + * target node + * 1 - when it has been queued + */ +static int add_virt_page_for_migration(struct mm_struct *mm, + const void __user *p, int node, struct list_head *pagelist, + bool migrate_all) +{ + struct vm_area_struct *vma; + unsigned long addr; + struct page *page; + int err = -EFAULT; + + mmap_read_lock(mm); + addr = (unsigned long)untagged_addr_remote(mm, p); + + vma = vma_lookup(mm, addr); + if (!vma || !vma_migratable(vma)) + goto out; + + /* FOLL_DUMP to ignore special (like zero) pages */ + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); + + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; + + err = -ENOENT; + if (!page) + goto out; + + err = add_page_for_migration(page, node, pagelist, migrate_all); + put_page(page); out: mmap_read_unlock(mm); @@ -2211,7 +2228,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, * Errors in the page lookup or isolation are not fatal and we simply * report them via status */ - err = add_page_for_migration(mm, p, current_node, &pagelist, + err = add_virt_page_for_migration(mm, p, current_node, &pagelist, flags & MPOL_MF_MOVE_ALL); if (err > 0) {
add_page_for_migration presently does two actions: 1) validates the page is present and migratable 2) isolates the page from LRU and puts it into the migration list Break add_page_for_migration into 2 functions: add_page_for_migration - isolate the page from LUR and add to list add_virt_page_for_migration - validate the page and call the above add_page_for_migration does not require the mm_struct and so can be re-used for a physical addressing version of move_pages Signed-off-by: Gregory Price <gregory.price@memverge.com> --- mm/migrate.c | 83 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 50 insertions(+), 33 deletions(-)