From: myoungwon oh <ohmyoungwon@gmail.com>
Date: Mon, 18 Mar 2024 06:48:07 +0000 (+0000)
Subject: crimson/os/seastore: cache metadata during trimming to prevent from disk read
X-Git-Tag: v20.0.0~2375^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=7f253ce5aa98018b5b209fd6e062078d151ad567;p=ceph.git

crimson/os/seastore: cache metadata during trimming to prevent from disk read

I encountered continous disk reads during trimming even though there are sufficient
cache available, in 4K random write test with RBM (RBD).
This is because metadata is note cached if its source is background transaction
within touch_extent(). So, seastore, including the trimming process,  needs to
constantly retrieve metadata (e.g., BACKREF_LEAF).

Signed-off-by: Myoungwon Oh <myoungwon.oh@samsung.com>
---

diff --git a/src/crimson/os/seastore/cache.h b/src/crimson/os/seastore/cache.h
index 75463f465fe1..829d57da1931 100644
--- a/src/crimson/os/seastore/cache.h
+++ b/src/crimson/os/seastore/cache.h
@@ -1342,8 +1342,11 @@ public:
       CachedExtent &ext,
       const Transaction::src_t* p_src=nullptr)
   {
-    if (p_src && is_background_transaction(*p_src))
+    if (p_src &&
+	is_background_transaction(*p_src) &&
+	is_logical_type(ext.get_type())) {
       return;
+    }
     if (ext.is_stable_clean() && !ext.is_placeholder()) {
       lru.move_to_top(ext);
     }