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From: Dennis Zhou <dennisszhou@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, Tejun Heo <tj@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Josef Bacik <josef@toxicpanda.com>
Cc: kernel-team@fb.com, linux-block@vger.kernel.org,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Dennis Zhou (Facebook)" <dennisszhou@gmail.com>
Subject: [PATCH 06/12] blkcg: associate a blkg for pages being evicted by swap
Date: Tue, 11 Sep 2018 14:41:31 -0400
Message-ID: <20180911184137.35897-7-dennisszhou@gmail.com> (raw)
In-Reply-To: <20180911184137.35897-1-dennisszhou@gmail.com>

From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>

A prior patch in this series added blkg association to bios issued by
cgroups. There are two other paths that we want to attribute work back
to the appropriate cgroup: swap and writeback. Here we modify the way
swap tags bios to include the blkg. Writeback will be tackle in the next
patch.

Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 block/bio.c         | 83 ++++++++++++++++++++++++++++++++-------------
 include/linux/bio.h | 11 ++++--
 mm/page_io.c        |  2 +-
 3 files changed, 68 insertions(+), 28 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 1d28d7ad2342..897c8ed9e572 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1957,30 +1957,6 @@ EXPORT_SYMBOL(bioset_init_from_src);
 
 #ifdef CONFIG_BLK_CGROUP
 
-#ifdef CONFIG_MEMCG
-/**
- * bio_associate_blkcg_from_page - associate a bio with the page's blkcg
- * @bio: target bio
- * @page: the page to lookup the blkcg from
- *
- * Associate @bio with the blkcg from @page's owning memcg.  This works like
- * every other associate function wrt references.
- */
-int bio_associate_blkcg_from_page(struct bio *bio, struct page *page)
-{
-	struct cgroup_subsys_state *blkcg_css;
-
-	if (unlikely(bio->bi_css))
-		return -EBUSY;
-	if (!page->mem_cgroup)
-		return 0;
-	blkcg_css = cgroup_get_e_css(page->mem_cgroup->css.cgroup,
-				     &io_cgrp_subsys);
-	bio->bi_css = blkcg_css;
-	return 0;
-}
-#endif /* CONFIG_MEMCG */
-
 /**
  * bio_associate_blkcg - associate a bio with the specified blkcg
  * @bio: target bio
@@ -2031,6 +2007,65 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg)
 	return 0;
 }
 
+static int __bio_associate_blkg_from_css(struct bio *bio,
+					 struct cgroup_subsys_state *css)
+{
+	struct blkcg_gq *blkg;
+
+	rcu_read_lock();
+
+	blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_disk->queue);
+
+	rcu_read_unlock();
+
+	return bio_associate_blkg(bio, blkg);
+}
+
+/**
+ * bio_associate_blkg_from_css - associate a bio with a specified css
+ * @bio: target bio
+ * @css: target css
+ *
+ * Associate @bio with the blkg found by combining the css's blkg and the
+ * request_queue of the @bio.  This takes a reference on the css that will
+ * be put upon freeing of @bio.
+ */
+int bio_associate_blkg_from_css(struct bio *bio,
+				struct cgroup_subsys_state *css)
+{
+	css_get(css);
+	bio->bi_css = css;
+	return __bio_associate_blkg_from_css(bio, css);
+}
+EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
+
+#ifdef CONFIG_MEMCG
+/**
+ * bio_associate_blkg_from_page - associate a bio with the page's blkg
+ * @bio: target bio
+ * @page: the page to lookup the blkcg from
+ *
+ * Associate @bio with the blkg from @page's owning memcg and the respective
+ * request_queue.  This works like every other associate function wrt
+ * references.
+ *
+ * Note: this must be called after bio has an associated device.
+ */
+int bio_associate_blkg_from_page(struct bio *bio, struct page *page)
+{
+	struct cgroup_subsys_state *css;
+
+	if (unlikely(bio->bi_css))
+		return -EBUSY;
+	if (!page->mem_cgroup)
+		return 0;
+	css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, &io_cgrp_subsys);
+	bio->bi_css = css;
+
+	return __bio_associate_blkg_from_css(bio, css);
+}
+#endif /* CONFIG_MEMCG */
+
 /**
  * bio_associate_create_blkg - associate a bio with a blkg from q
  * @q: request_queue where bio is going
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 829cd0bb407d..c73a870ebc0e 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -533,21 +533,26 @@ do {						\
 	disk_devt((bio)->bi_disk)
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
-int bio_associate_blkcg_from_page(struct bio *bio, struct page *page);
+int bio_associate_blkg_from_page(struct bio *bio, struct page *page);
 #else
-static inline int bio_associate_blkcg_from_page(struct bio *bio,
-						struct page *page) {  return 0; }
+static inline int bio_associate_blkg_from_page(struct bio *bio,
+					       struct page *page) { return 0; }
 #endif
 
 #ifdef CONFIG_BLK_CGROUP
 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg);
+int bio_associate_blkg_from_css(struct bio *bio,
+				struct cgroup_subsys_state *css);
 int bio_associate_create_blkg(struct request_queue *q, struct bio *bio);
 void bio_disassociate_task(struct bio *bio);
 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 #else	/* CONFIG_BLK_CGROUP */
 static inline int bio_associate_blkcg(struct bio *bio,
 			struct cgroup_subsys_state *blkcg_css) { return 0; }
+static inline int bio_associate_blkg_from_css(struct bio *bio,
+					      struct cgroup_subsys_state *css)
+{ return 0; }
 static inline int bio_associate_create_blkg(struct request_queue *q,
 					    struct bio *bio) { return 0; }
 static inline void bio_disassociate_task(struct bio *bio) { }
diff --git a/mm/page_io.c b/mm/page_io.c
index aafd19ec1db4..573d3663d846 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -339,7 +339,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc,
 		goto out;
 	}
 	bio->bi_opf = REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc);
-	bio_associate_blkcg_from_page(bio, page);
+	bio_associate_blkg_from_page(bio, page);
 	count_swpout_vm_event(page);
 	set_page_writeback(page);
 	unlock_page(page);
-- 
2.17.1


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-11 18:41 [PATCH v3 00/12] block: always associate blkg and refcount cleanup Dennis Zhou
2018-09-11 18:41 ` [PATCH 01/12] blkcg: fix ref count issue with bio_blkcg using task_css Dennis Zhou
2018-09-11 18:41 ` [PATCH 02/12] blkcg: update blkg_lookup_create to do locking Dennis Zhou
2018-09-11 18:41 ` [PATCH 03/12] blkcg: convert blkg_lookup_create to find closest blkg Dennis Zhou
2018-09-11 23:50   ` Tejun Heo
2018-09-11 18:41 ` [PATCH 04/12] blkcg: always associate a bio with a blkg Dennis Zhou
2018-09-11 18:41 ` [PATCH 05/12] blkcg: consolidate bio_issue_init to be a part of core Dennis Zhou
2018-09-11 18:41 ` Dennis Zhou [this message]
2018-09-11 18:41 ` [PATCH 07/12] blkcg: associate writeback bios with a blkg Dennis Zhou
2018-09-11 18:41 ` [PATCH 08/12] blkcg: remove bio->bi_css and instead use bio->bi_blkg Dennis Zhou
2018-09-11 18:41 ` [PATCH 09/12] blkcg: remove additional reference to the css Dennis Zhou
2018-09-11 23:51   ` Tejun Heo
2018-09-11 18:41 ` [PATCH 10/12] blkcg: cleanup and make blk_get_rl use blkg_lookup_create Dennis Zhou
2018-09-11 18:41 ` [PATCH 11/12] blkcg: change blkg reference counting to use percpu_ref Dennis Zhou
2018-09-11 18:41 ` [PATCH 12/12] blkcg: rename blkg_try_get to blkg_tryget Dennis Zhou
2018-09-21 20:56 ` [PATCH v3 00/12] block: always associate blkg and refcount cleanup Dennis Zhou
2018-09-22  2:29   ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2018-09-06 21:10 [PATCH " Dennis Zhou
2018-09-06 21:10 ` [PATCH 06/12] blkcg: associate a blkg for pages being evicted by swap Dennis Zhou

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