From 3a52716cc9465a600f7e0e093dc33862615eb90e Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Wed, 10 Jul 2019 10:21:12 -0500
Subject: [PATCH] bluestore: print aio in batch

KernelDevice::aio_{submit,write,read}() are critical paths. calling
cct->_conf->subsys.should_gather() multi-times is not optimal. the
downside of this issue is that if the aio is printed, the size of
buffer in PrebufferedStreambuf could be large if the number of iov is
large, that could be a heavy load to the memory subsystem.

Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit 67c6f768add46d92d9403ca6b7709b892d8a686d)

# Conflicts:
#	src/os/bluestore/aio.cc
 - adjacent to aio_queue_t::submit()
---
 src/os/bluestore/KernelDevice.cc | 15 +++------------
 src/os/bluestore/aio.cc          | 11 +++++++++++
 src/os/bluestore/aio.h           |  2 ++
 3 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/os/bluestore/KernelDevice.cc b/src/os/bluestore/KernelDevice.cc
index 124a29bbdbcfd..6d34f0935ae7b 100644
--- a/src/os/bluestore/KernelDevice.cc
+++ b/src/os/bluestore/KernelDevice.cc
@@ -531,10 +531,7 @@ void KernelDevice::aio_submit(IOContext *ioc)
   if (cct->_conf->bdev_debug_aio) {
     list<aio_t>::iterator p = ioc->running_aios.begin();
     while (p != e) {
-      for (auto& io : p->iov)
-	dout(30) << __func__ << "   iov " << (void*)io.iov_base
-		 << " len " << io.iov_len << dendl;
-
+      dout(30) << __func__ << " " << *p << dendl;
       std::lock_guard<std::mutex> l(debug_queue_lock);
       debug_aio_link(*p++);
     }
@@ -658,10 +655,7 @@ int KernelDevice::aio_write(
       ++injecting_crash;
     } else {
       bl.prepare_iov(&aio.iov);
-      for (unsigned i=0; i<aio.iov.size(); ++i) {
-	dout(30) << "aio " << i << " " << aio.iov[i].iov_base
-		 << " " << aio.iov[i].iov_len << dendl;
-      }
+      dout(30) << aio << dendl;
       aio.bl.claim_append(bl);
       aio.pwritev(off, len);
     }
@@ -733,10 +727,7 @@ int KernelDevice::aio_read(
     ++ioc->num_pending;
     aio_t& aio = ioc->pending_aios.back();
     aio.pread(off, len);
-    for (unsigned i=0; i<aio.iov.size(); ++i) {
-      dout(30) << "aio " << i << " " << aio.iov[i].iov_base
-	       << " " << aio.iov[i].iov_len << dendl;
-    }
+    dout(30) << aio << dendl;
     pbl->append(aio.bl);
     dout(5) << __func__ << " 0x" << std::hex << off << "~" << len
 	    << std::dec << " aio " << &aio << dendl;
diff --git a/src/os/bluestore/aio.cc b/src/os/bluestore/aio.cc
index 256f3db97fd55..656054f266982 100644
--- a/src/os/bluestore/aio.cc
+++ b/src/os/bluestore/aio.cc
@@ -30,6 +30,17 @@ int aio_queue_t::submit(aio_t &aio, int *retries)
   return r;
 }
 
+std::ostream& operator<<(std::ostream& os, const aio_t& aio)
+{
+  unsigned i = 0;
+  os << "aio: ";
+  for (auto& iov : aio.iov) {
+    os << "\n [" << i++ << "] 0x"
+       << std::hex << iov.iov_base << "~" << iov.iov_len << std::dec;
+  }
+  return os;
+}
+
 int aio_queue_t::submit_batch(aio_iter begin, aio_iter end, 
 			      uint16_t aios_size, void *priv, 
 			      int *retries)
diff --git a/src/os/bluestore/aio.h b/src/os/bluestore/aio.h
index b2739d44cbe54..1095aa0034488 100644
--- a/src/os/bluestore/aio.h
+++ b/src/os/bluestore/aio.h
@@ -45,6 +45,8 @@ struct aio_t {
   }
 };
 
+std::ostream& operator<<(std::ostream& os, const aio_t& aio);
+
 typedef boost::intrusive::list<
   aio_t,
   boost::intrusive::member_hook<
-- 
2.39.5