| Message ID | 20220524060551.80037-5-songmuchun@bytedance.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Use obj_cgroup APIs to charge the LRU pages | expand |
On Tue, May 24, 2022 at 02:05:44PM +0800, Muchun Song wrote: > In the later patch, we will reparent the LRU pages. The pages moved to > appropriate LRU list can be reparented during the process of the > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > should use the more general interface of folio_lruvec_relock_irq() to > acquire the correct lruvec lock. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ > 1 file changed, 25 insertions(+), 24 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 1678802e03e7..761d5e0dd78d 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > * move_pages_to_lru() moves pages from private @list to appropriate LRU list. > * On return, @list is reused as a list of pages to be freed by the caller. > * > - * Returns the number of pages moved to the given lruvec. > + * Returns the number of pages moved to the appropriate LRU list. > + * > + * Note: The caller must not hold any lruvec lock. > */ > -static unsigned int move_pages_to_lru(struct lruvec *lruvec, > - struct list_head *list) > +static unsigned int move_pages_to_lru(struct list_head *list) > { > - int nr_pages, nr_moved = 0; > + int nr_moved = 0; > + struct lruvec *lruvec = NULL; > LIST_HEAD(pages_to_free); > - struct page *page; > > while (!list_empty(list)) { > - page = lru_to_page(list); > + int nr_pages; > + struct folio *folio = lru_to_folio(list); > + struct page *page = &folio->page; > + > + lruvec = folio_lruvec_relock_irq(folio, lruvec); > VM_BUG_ON_PAGE(PageLRU(page), page); > list_del(&page->lru); > if (unlikely(!page_evictable(page))) { > - spin_unlock_irq(&lruvec->lru_lock); > + unlock_page_lruvec_irq(lruvec); Better to stick with the opencoded unlock. It matches a bit better with the locking function, compared to locking folio and unlocking page... Aside from that, this looks good: Acked-by: Johannes Weiner <hannes@cmpxchg.org>
On 5/24/22 02:05, Muchun Song wrote: > In the later patch, we will reparent the LRU pages. The pages moved to > appropriate LRU list can be reparented during the process of the > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > should use the more general interface of folio_lruvec_relock_irq() to > acquire the correct lruvec lock. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ > 1 file changed, 25 insertions(+), 24 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 1678802e03e7..761d5e0dd78d 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > * move_pages_to_lru() moves pages from private @list to appropriate LRU list. > * On return, @list is reused as a list of pages to be freed by the caller. > * > - * Returns the number of pages moved to the given lruvec. > + * Returns the number of pages moved to the appropriate LRU list. > + * > + * Note: The caller must not hold any lruvec lock. > */ > -static unsigned int move_pages_to_lru(struct lruvec *lruvec, > - struct list_head *list) > +static unsigned int move_pages_to_lru(struct list_head *list) > { > - int nr_pages, nr_moved = 0; > + int nr_moved = 0; > + struct lruvec *lruvec = NULL; > LIST_HEAD(pages_to_free); > - struct page *page; > > while (!list_empty(list)) { > - page = lru_to_page(list); > + int nr_pages; > + struct folio *folio = lru_to_folio(list); > + struct page *page = &folio->page; > + > + lruvec = folio_lruvec_relock_irq(folio, lruvec); > VM_BUG_ON_PAGE(PageLRU(page), page); > list_del(&page->lru); > if (unlikely(!page_evictable(page))) { > - spin_unlock_irq(&lruvec->lru_lock); > + unlock_page_lruvec_irq(lruvec); > putback_lru_page(page); > - spin_lock_irq(&lruvec->lru_lock); > + lruvec = NULL; > continue; > } > > @@ -2267,20 +2272,16 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > __clear_page_lru_flags(page); > > if (unlikely(PageCompound(page))) { > - spin_unlock_irq(&lruvec->lru_lock); > + unlock_page_lruvec_irq(lruvec); > destroy_compound_page(page); > - spin_lock_irq(&lruvec->lru_lock); > + lruvec = NULL; > } else > list_add(&page->lru, &pages_to_free); > > continue; > } > > - /* > - * All pages were isolated from the same lruvec (and isolation > - * inhibits memcg migration). > - */ > - VM_BUG_ON_PAGE(!folio_matches_lruvec(page_folio(page), lruvec), page); > + VM_BUG_ON_PAGE(!folio_matches_lruvec(folio, lruvec), page); > add_page_to_lru_list(page, lruvec); > nr_pages = thp_nr_pages(page); > nr_moved += nr_pages; > @@ -2288,6 +2289,8 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > workingset_age_nonresident(lruvec, nr_pages); > } > > + if (lruvec) > + unlock_page_lruvec_irq(lruvec); > /* > * To save our caller's stack, now use input list for pages to free. > */ > @@ -2359,16 +2362,16 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > > nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false); > > - spin_lock_irq(&lruvec->lru_lock); > - move_pages_to_lru(lruvec, &page_list); > + move_pages_to_lru(&page_list); > > + local_irq_disable(); > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > if (!cgroup_reclaim(sc)) > __count_vm_events(item, nr_reclaimed); > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); > - spin_unlock_irq(&lruvec->lru_lock); > + local_irq_enable(); > > lru_note_cost(lruvec, file, stat.nr_pageout); > mem_cgroup_uncharge_list(&page_list); > @@ -2498,18 +2501,16 @@ static void shrink_active_list(unsigned long nr_to_scan, > /* > * Move pages back to the lru list. > */ > - spin_lock_irq(&lruvec->lru_lock); > - > - nr_activate = move_pages_to_lru(lruvec, &l_active); > - nr_deactivate = move_pages_to_lru(lruvec, &l_inactive); > + nr_activate = move_pages_to_lru(&l_active); > + nr_deactivate = move_pages_to_lru(&l_inactive); > /* Keep all free pages in l_active list */ > list_splice(&l_inactive, &l_active); > > + local_irq_disable(); > __count_vm_events(PGDEACTIVATE, nr_deactivate); > __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); > - > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > - spin_unlock_irq(&lruvec->lru_lock); > + local_irq_enable(); > > mem_cgroup_uncharge_list(&l_active); > free_unref_page_list(&l_active); Note that the RT engineers will likely change the local_irq_disable()/local_irq_enable() to local_lock_irq()/local_unlock_irq(). Cheers, Longman
On Tue, May 24, 2022 at 02:05:44PM +0800, Muchun Song wrote: > In the later patch, we will reparent the LRU pages. The pages moved to > appropriate LRU list can be reparented during the process of the > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > should use the more general interface of folio_lruvec_relock_irq() to > acquire the correct lruvec lock. > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> With changes asked by Johannes : Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Thanks!
On Tue, May 24, 2022 at 03:38:50PM -0400, Johannes Weiner wrote: > On Tue, May 24, 2022 at 02:05:44PM +0800, Muchun Song wrote: > > In the later patch, we will reparent the LRU pages. The pages moved to > > appropriate LRU list can be reparented during the process of the > > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > > should use the more general interface of folio_lruvec_relock_irq() to > > acquire the correct lruvec lock. > > > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > > --- > > mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ > > 1 file changed, 25 insertions(+), 24 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 1678802e03e7..761d5e0dd78d 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > > * move_pages_to_lru() moves pages from private @list to appropriate LRU list. > > * On return, @list is reused as a list of pages to be freed by the caller. > > * > > - * Returns the number of pages moved to the given lruvec. > > + * Returns the number of pages moved to the appropriate LRU list. > > + * > > + * Note: The caller must not hold any lruvec lock. > > */ > > -static unsigned int move_pages_to_lru(struct lruvec *lruvec, > > - struct list_head *list) > > +static unsigned int move_pages_to_lru(struct list_head *list) > > { > > - int nr_pages, nr_moved = 0; > > + int nr_moved = 0; > > + struct lruvec *lruvec = NULL; > > LIST_HEAD(pages_to_free); > > - struct page *page; > > > > while (!list_empty(list)) { > > - page = lru_to_page(list); > > + int nr_pages; > > + struct folio *folio = lru_to_folio(list); > > + struct page *page = &folio->page; > > + > > + lruvec = folio_lruvec_relock_irq(folio, lruvec); > > VM_BUG_ON_PAGE(PageLRU(page), page); > > list_del(&page->lru); > > if (unlikely(!page_evictable(page))) { > > - spin_unlock_irq(&lruvec->lru_lock); > > + unlock_page_lruvec_irq(lruvec); > > Better to stick with the opencoded unlock. It matches a bit better > with the locking function, compared to locking folio and unlocking > page... > Seems like we are missing folio unlock variants. How about intriducing folio_lruvec_unlock() variants? There are a lot of places where locking folio and unlocking page. Thanks. > Aside from that, this looks good: > > Acked-by: Johannes Weiner <hannes@cmpxchg.org> > Thanks.
On Tue, May 24, 2022 at 07:43:03PM -0700, Roman Gushchin wrote: > On Tue, May 24, 2022 at 02:05:44PM +0800, Muchun Song wrote: > > In the later patch, we will reparent the LRU pages. The pages moved to > > appropriate LRU list can be reparented during the process of the > > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > > should use the more general interface of folio_lruvec_relock_irq() to > > acquire the correct lruvec lock. > > > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > > With changes asked by Johannes : > > Acked-by: Roman Gushchin <roman.gushchin@linux.dev> > Thanks Roman.
On Tue, May 24, 2022 at 03:52:22PM -0400, Waiman Long wrote: > On 5/24/22 02:05, Muchun Song wrote: > > In the later patch, we will reparent the LRU pages. The pages moved to > > appropriate LRU list can be reparented during the process of the > > move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we > > should use the more general interface of folio_lruvec_relock_irq() to > > acquire the correct lruvec lock. > > > > Signed-off-by: Muchun Song <songmuchun@bytedance.com> > > --- > > mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ > > 1 file changed, 25 insertions(+), 24 deletions(-) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 1678802e03e7..761d5e0dd78d 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, > > * move_pages_to_lru() moves pages from private @list to appropriate LRU list. > > * On return, @list is reused as a list of pages to be freed by the caller. > > * > > - * Returns the number of pages moved to the given lruvec. > > + * Returns the number of pages moved to the appropriate LRU list. > > + * > > + * Note: The caller must not hold any lruvec lock. > > */ > > -static unsigned int move_pages_to_lru(struct lruvec *lruvec, > > - struct list_head *list) > > +static unsigned int move_pages_to_lru(struct list_head *list) > > { > > - int nr_pages, nr_moved = 0; > > + int nr_moved = 0; > > + struct lruvec *lruvec = NULL; > > LIST_HEAD(pages_to_free); > > - struct page *page; > > while (!list_empty(list)) { > > - page = lru_to_page(list); > > + int nr_pages; > > + struct folio *folio = lru_to_folio(list); > > + struct page *page = &folio->page; > > + > > + lruvec = folio_lruvec_relock_irq(folio, lruvec); > > VM_BUG_ON_PAGE(PageLRU(page), page); > > list_del(&page->lru); > > if (unlikely(!page_evictable(page))) { > > - spin_unlock_irq(&lruvec->lru_lock); > > + unlock_page_lruvec_irq(lruvec); > > putback_lru_page(page); > > - spin_lock_irq(&lruvec->lru_lock); > > + lruvec = NULL; > > continue; > > } > > @@ -2267,20 +2272,16 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > > __clear_page_lru_flags(page); > > if (unlikely(PageCompound(page))) { > > - spin_unlock_irq(&lruvec->lru_lock); > > + unlock_page_lruvec_irq(lruvec); > > destroy_compound_page(page); > > - spin_lock_irq(&lruvec->lru_lock); > > + lruvec = NULL; > > } else > > list_add(&page->lru, &pages_to_free); > > continue; > > } > > - /* > > - * All pages were isolated from the same lruvec (and isolation > > - * inhibits memcg migration). > > - */ > > - VM_BUG_ON_PAGE(!folio_matches_lruvec(page_folio(page), lruvec), page); > > + VM_BUG_ON_PAGE(!folio_matches_lruvec(folio, lruvec), page); > > add_page_to_lru_list(page, lruvec); > > nr_pages = thp_nr_pages(page); > > nr_moved += nr_pages; > > @@ -2288,6 +2289,8 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, > > workingset_age_nonresident(lruvec, nr_pages); > > } > > + if (lruvec) > > + unlock_page_lruvec_irq(lruvec); > > /* > > * To save our caller's stack, now use input list for pages to free. > > */ > > @@ -2359,16 +2362,16 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > > nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false); > > - spin_lock_irq(&lruvec->lru_lock); > > - move_pages_to_lru(lruvec, &page_list); > > + move_pages_to_lru(&page_list); > > + local_irq_disable(); > > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > > item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; > > if (!cgroup_reclaim(sc)) > > __count_vm_events(item, nr_reclaimed); > > __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); > > __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); > > - spin_unlock_irq(&lruvec->lru_lock); > > + local_irq_enable(); > > lru_note_cost(lruvec, file, stat.nr_pageout); > > mem_cgroup_uncharge_list(&page_list); > > @@ -2498,18 +2501,16 @@ static void shrink_active_list(unsigned long nr_to_scan, > > /* > > * Move pages back to the lru list. > > */ > > - spin_lock_irq(&lruvec->lru_lock); > > - > > - nr_activate = move_pages_to_lru(lruvec, &l_active); > > - nr_deactivate = move_pages_to_lru(lruvec, &l_inactive); > > + nr_activate = move_pages_to_lru(&l_active); > > + nr_deactivate = move_pages_to_lru(&l_inactive); > > /* Keep all free pages in l_active list */ > > list_splice(&l_inactive, &l_active); > > + local_irq_disable(); > > __count_vm_events(PGDEACTIVATE, nr_deactivate); > > __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); > > - > > __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); > > - spin_unlock_irq(&lruvec->lru_lock); > > + local_irq_enable(); > > mem_cgroup_uncharge_list(&l_active); > > free_unref_page_list(&l_active); > > Note that the RT engineers will likely change the > local_irq_disable()/local_irq_enable() to > local_lock_irq()/local_unlock_irq(). > Thanks. I'll replace them with local_lock/unlock_irq().
diff --git a/mm/vmscan.c b/mm/vmscan.c index 1678802e03e7..761d5e0dd78d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2230,23 +2230,28 @@ static int too_many_isolated(struct pglist_data *pgdat, int file, * move_pages_to_lru() moves pages from private @list to appropriate LRU list. * On return, @list is reused as a list of pages to be freed by the caller. * - * Returns the number of pages moved to the given lruvec. + * Returns the number of pages moved to the appropriate LRU list. + * + * Note: The caller must not hold any lruvec lock. */ -static unsigned int move_pages_to_lru(struct lruvec *lruvec, - struct list_head *list) +static unsigned int move_pages_to_lru(struct list_head *list) { - int nr_pages, nr_moved = 0; + int nr_moved = 0; + struct lruvec *lruvec = NULL; LIST_HEAD(pages_to_free); - struct page *page; while (!list_empty(list)) { - page = lru_to_page(list); + int nr_pages; + struct folio *folio = lru_to_folio(list); + struct page *page = &folio->page; + + lruvec = folio_lruvec_relock_irq(folio, lruvec); VM_BUG_ON_PAGE(PageLRU(page), page); list_del(&page->lru); if (unlikely(!page_evictable(page))) { - spin_unlock_irq(&lruvec->lru_lock); + unlock_page_lruvec_irq(lruvec); putback_lru_page(page); - spin_lock_irq(&lruvec->lru_lock); + lruvec = NULL; continue; } @@ -2267,20 +2272,16 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, __clear_page_lru_flags(page); if (unlikely(PageCompound(page))) { - spin_unlock_irq(&lruvec->lru_lock); + unlock_page_lruvec_irq(lruvec); destroy_compound_page(page); - spin_lock_irq(&lruvec->lru_lock); + lruvec = NULL; } else list_add(&page->lru, &pages_to_free); continue; } - /* - * All pages were isolated from the same lruvec (and isolation - * inhibits memcg migration). - */ - VM_BUG_ON_PAGE(!folio_matches_lruvec(page_folio(page), lruvec), page); + VM_BUG_ON_PAGE(!folio_matches_lruvec(folio, lruvec), page); add_page_to_lru_list(page, lruvec); nr_pages = thp_nr_pages(page); nr_moved += nr_pages; @@ -2288,6 +2289,8 @@ static unsigned int move_pages_to_lru(struct lruvec *lruvec, workingset_age_nonresident(lruvec, nr_pages); } + if (lruvec) + unlock_page_lruvec_irq(lruvec); /* * To save our caller's stack, now use input list for pages to free. */ @@ -2359,16 +2362,16 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, &stat, false); - spin_lock_irq(&lruvec->lru_lock); - move_pages_to_lru(lruvec, &page_list); + move_pages_to_lru(&page_list); + local_irq_disable(); __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; if (!cgroup_reclaim(sc)) __count_vm_events(item, nr_reclaimed); __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); __count_vm_events(PGSTEAL_ANON + file, nr_reclaimed); - spin_unlock_irq(&lruvec->lru_lock); + local_irq_enable(); lru_note_cost(lruvec, file, stat.nr_pageout); mem_cgroup_uncharge_list(&page_list); @@ -2498,18 +2501,16 @@ static void shrink_active_list(unsigned long nr_to_scan, /* * Move pages back to the lru list. */ - spin_lock_irq(&lruvec->lru_lock); - - nr_activate = move_pages_to_lru(lruvec, &l_active); - nr_deactivate = move_pages_to_lru(lruvec, &l_inactive); + nr_activate = move_pages_to_lru(&l_active); + nr_deactivate = move_pages_to_lru(&l_inactive); /* Keep all free pages in l_active list */ list_splice(&l_inactive, &l_active); + local_irq_disable(); __count_vm_events(PGDEACTIVATE, nr_deactivate); __count_memcg_events(lruvec_memcg(lruvec), PGDEACTIVATE, nr_deactivate); - __mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken); - spin_unlock_irq(&lruvec->lru_lock); + local_irq_enable(); mem_cgroup_uncharge_list(&l_active); free_unref_page_list(&l_active);
In the later patch, we will reparent the LRU pages. The pages moved to appropriate LRU list can be reparented during the process of the move_pages_to_lru(). So holding a lruvec lock by the caller is wrong, we should use the more general interface of folio_lruvec_relock_irq() to acquire the correct lruvec lock. Signed-off-by: Muchun Song <songmuchun@bytedance.com> --- mm/vmscan.c | 49 +++++++++++++++++++++++++------------------------ 1 file changed, 25 insertions(+), 24 deletions(-)