diff mbox series

[RFC,v1,1/2] mm: vmscan: refactor updating reclaimed pages in reclaim_state

Message ID 20230202233229.3895713-2-yosryahmed@google.com
State New
Headers
Series Ignore non-LRU-based reclaim in memcg reclaim |

Commit Message

Yosry Ahmed Feb. 2, 2023, 11:32 p.m. UTC 
  During reclaim, we keep track of pages reclaimed from other means than
LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab,
which we stash a pointer to in current task_struct.

However, we keep track of more than just reclaimed slab pages through
this. We also use it for clean file pages dropped through pruned inodes,
and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add
a helper function that wraps updating it through current.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
---
 fs/inode.c           |  3 +--
 fs/xfs/xfs_buf.c     |  3 +--
 include/linux/swap.h |  5 ++++-
 mm/slab.c            |  3 +--
 mm/slob.c            |  6 ++----
 mm/slub.c            |  5 ++---
 mm/vmscan.c          | 17 +++++++++++++++--
 7 files changed, 26 insertions(+), 16 deletions(-)

Comments

Matthew Wilcox Feb. 3, 2023, 4:22 p.m. UTC | #1 
On Thu, Feb 02, 2023 at 11:32:28PM +0000, Yosry Ahmed wrote:
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 54c774af6e1c..060079f1e966 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -286,8 +286,7 @@ xfs_buf_free_pages(
>  		if (bp->b_pages[i])
>  			__free_page(bp->b_pages[i]);
>  	}
> -	if (current->reclaim_state)
> -		current->reclaim_state->reclaimed_slab += bp->b_page_count;
> +	report_freed_pages(bp->b_page_count);

XFS can be built as a module

> +++ b/mm/vmscan.c
> @@ -204,6 +204,19 @@ static void set_task_reclaim_state(struct task_struct *task,
>  	task->reclaim_state = rs;
>  }
>  
> +/*
> + * reclaim_report_freed_pages: report pages freed outside of LRU-based reclaim
> + * @pages: number of pages freed
> + *
> + * If the current process is undergoing a reclaim operation,
> + * increment the number of reclaimed pages by @pages.
> + */
> +void report_freed_pages(unsigned long pages)
> +{
> +	if (current->reclaim_state)
> +		current->reclaim_state->reclaimed += pages;
> +}
> +

report_free_pages is not EXPORT_SYMBOLed
Yosry Ahmed Feb. 3, 2023, 10:30 p.m. UTC | #2 
On Fri, Feb 3, 2023 at 8:22 AM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Thu, Feb 02, 2023 at 11:32:28PM +0000, Yosry Ahmed wrote:
> > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> > index 54c774af6e1c..060079f1e966 100644
> > --- a/fs/xfs/xfs_buf.c
> > +++ b/fs/xfs/xfs_buf.c
> > @@ -286,8 +286,7 @@ xfs_buf_free_pages(
> >               if (bp->b_pages[i])
> >                       __free_page(bp->b_pages[i]);
> >       }
> > -     if (current->reclaim_state)
> > -             current->reclaim_state->reclaimed_slab += bp->b_page_count;
> > +     report_freed_pages(bp->b_page_count);
>
> XFS can be built as a module

I didn't know that, thanks for pointing it out!

>
> > +++ b/mm/vmscan.c
> > @@ -204,6 +204,19 @@ static void set_task_reclaim_state(struct task_struct *task,
> >       task->reclaim_state = rs;
> >  }
> >
> > +/*
> > + * reclaim_report_freed_pages: report pages freed outside of LRU-based reclaim
> > + * @pages: number of pages freed
> > + *
> > + * If the current process is undergoing a reclaim operation,
> > + * increment the number of reclaimed pages by @pages.
> > + */
> > +void report_freed_pages(unsigned long pages)
> > +{
> > +     if (current->reclaim_state)
> > +             current->reclaim_state->reclaimed += pages;
> > +}
> > +
>
> report_free_pages is not EXPORT_SYMBOLed

Will do that for the next version, thanks!
diff mbox series

Patch

diff --git a/fs/inode.c b/fs/inode.c
index f453eb58fd03..adf0a7725054 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -863,8 +863,7 @@  static enum lru_status inode_lru_isolate(struct list_head *item,
 				__count_vm_events(KSWAPD_INODESTEAL, reap);
 			else
 				__count_vm_events(PGINODESTEAL, reap);
-			if (current->reclaim_state)
-				current->reclaim_state->reclaimed_slab += reap;
+			report_freed_pages(reap);
 		}
 		iput(inode);
 		spin_lock(lru_lock);
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 54c774af6e1c..060079f1e966 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -286,8 +286,7 @@  xfs_buf_free_pages(
 		if (bp->b_pages[i])
 			__free_page(bp->b_pages[i]);
 	}
-	if (current->reclaim_state)
-		current->reclaim_state->reclaimed_slab += bp->b_page_count;
+	report_freed_pages(bp->b_page_count);
 
 	if (bp->b_pages != bp->b_page_array)
 		kmem_free(bp->b_pages);
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2787b84eaf12..bc1d8b326453 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -153,13 +153,16 @@  union swap_header {
  * memory reclaim
  */
 struct reclaim_state {
-	unsigned long reclaimed_slab;
+	/* pages reclaimed outside of LRU-based reclaim */
+	unsigned long reclaimed;
 #ifdef CONFIG_LRU_GEN
 	/* per-thread mm walk data */
 	struct lru_gen_mm_walk *mm_walk;
 #endif
 };
 
+void report_freed_pages(unsigned long pages);
+
 #ifdef __KERNEL__
 
 struct address_space;
diff --git a/mm/slab.c b/mm/slab.c
index 29300fc1289a..452db5913356 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1395,8 +1395,7 @@  static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab)
 	smp_wmb();
 	__folio_clear_slab(folio);
 
-	if (current->reclaim_state)
-		current->reclaim_state->reclaimed_slab += 1 << order;
+	report_freed_pages(1 << order);
 	unaccount_slab(slab, order, cachep);
 	__free_pages(folio_page(folio, 0), order);
 }
diff --git a/mm/slob.c b/mm/slob.c
index fe567fcfa3a3..71ee00e9dd46 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -61,7 +61,7 @@ 
 #include <linux/slab.h>
 
 #include <linux/mm.h>
-#include <linux/swap.h> /* struct reclaim_state */
+#include <linux/swap.h> /* report_freed_pages() */
 #include <linux/cache.h>
 #include <linux/init.h>
 #include <linux/export.h>
@@ -211,9 +211,7 @@  static void slob_free_pages(void *b, int order)
 {
 	struct page *sp = virt_to_page(b);
 
-	if (current->reclaim_state)
-		current->reclaim_state->reclaimed_slab += 1 << order;
-
+	report_freed_pages(1 << order);
 	mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B,
 			    -(PAGE_SIZE << order));
 	__free_pages(sp, order);
diff --git a/mm/slub.c b/mm/slub.c
index 13459c69095a..5145ad2467e9 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -11,7 +11,7 @@ 
  */
 
 #include <linux/mm.h>
-#include <linux/swap.h> /* struct reclaim_state */
+#include <linux/swap.h> /* report_freed_pages() */
 #include <linux/module.h>
 #include <linux/bit_spinlock.h>
 #include <linux/interrupt.h>
@@ -2063,8 +2063,7 @@  static void __free_slab(struct kmem_cache *s, struct slab *slab)
 	/* Make the mapping reset visible before clearing the flag */
 	smp_wmb();
 	__folio_clear_slab(folio);
-	if (current->reclaim_state)
-		current->reclaim_state->reclaimed_slab += pages;
+	report_freed_pages(pages);
 	unaccount_slab(slab, order, s);
 	__free_pages(folio_page(folio, 0), order);
 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bd6637fcd8f9..63a27d2f6f31 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -204,6 +204,19 @@  static void set_task_reclaim_state(struct task_struct *task,
 	task->reclaim_state = rs;
 }
 
+/*
+ * reclaim_report_freed_pages: report pages freed outside of LRU-based reclaim
+ * @pages: number of pages freed
+ *
+ * If the current process is undergoing a reclaim operation,
+ * increment the number of reclaimed pages by @pages.
+ */
+void report_freed_pages(unsigned long pages)
+{
+	if (current->reclaim_state)
+		current->reclaim_state->reclaimed += pages;
+}
+
 LIST_HEAD(shrinker_list);
 DECLARE_RWSEM(shrinker_rwsem);
 
@@ -6169,8 +6182,8 @@  static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
 	shrink_node_memcgs(pgdat, sc);
 
 	if (reclaim_state) {
-		sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-		reclaim_state->reclaimed_slab = 0;
+		sc->nr_reclaimed += reclaim_state->reclaimed;
+		reclaim_state->reclaimed = 0;
 	}
 
 	/* Record the subtree's reclaim efficiency */