SourceFormat Enforcement

[thirdparty/squid.git] / src / servers / Server.cc

diff --git a/src/servers/Server.cc b/src/servers/Server.cc
index c3b3608ab00f9ae3c099dd3e29af03edb7edf9cb..d10597e676240fa0d3405d505245bf6a59f70ef0 100644 (file)
--- a/src/servers/Server.cc
+++ b/src/servers/Server.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1996-2016 The Squid Software Foundation and contributors
+ * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
  *
  * Squid software is distributed under GPLv2+ license and includes
  * contributions from numerous individuals and organizations.
@@ -24,12 +24,10 @@
 Server::Server(const MasterXaction::Pointer &xact) :
     AsyncJob("::Server"), // kids overwrite
     clientConnection(xact->tcpClient),
+    transferProtocol(xact->squidPort->transport),
     port(xact->squidPort),
     receivedFirstByte_(false)
-{
-    if (xact->squidPort)
-        transferProtocol = xact->squidPort->transport;
-}
+{}
 
 bool
 Server::doneAll() const
@@ -63,26 +61,24 @@ Server::stopReading()
     }
 }
 
-bool
+/// Prepare inBuf for I/O. This method balances several conflicting desires:
+/// 1. Do not read too few bytes at a time.
+/// 2. Do not waste too much buffer space.
+/// 3. Do not [re]allocate or memmove the buffer too much.
+/// 4. Obey Config.maxRequestBufferSize limit.
+void
 Server::maybeMakeSpaceAvailable()
 {
-    if (inBuf.spaceSize() < 2) {
-        const SBuf::size_type haveCapacity = inBuf.length() + inBuf.spaceSize();
-        if (haveCapacity >= Config.maxRequestBufferSize) {
-            debugs(33, 4, "request buffer full: client_request_buffer_max_size=" << Config.maxRequestBufferSize);
-            return false;
-        }
-        if (haveCapacity == 0) {
-            // haveCapacity is based on the SBuf visible window of the MemBlob buffer, which may fill up.
-            // at which point bump the buffer back to default. This allocates a new MemBlob with any un-parsed bytes.
-            inBuf.reserveCapacity(CLIENT_REQ_BUF_SZ);
-        } else {
-            const SBuf::size_type wantCapacity = min(static_cast<SBuf::size_type>(Config.maxRequestBufferSize), haveCapacity*2);
-            inBuf.reserveCapacity(wantCapacity);
-        }
-        debugs(33, 2, "growing request buffer: available=" << inBuf.spaceSize() << " used=" << inBuf.length());
-    }
-    return (inBuf.spaceSize() >= 2);
+    // The hard-coded parameters are arbitrary but seem reasonable.
+    // A careful study of Squid I/O and parsing patterns is needed to tune them.
+    SBufReservationRequirements requirements;
+    requirements.minSpace = 1024; // smaller I/Os are not worth their overhead
+    requirements.idealSpace = CLIENT_REQ_BUF_SZ; // we expect few larger I/Os
+    requirements.maxCapacity = Config.maxRequestBufferSize;
+    requirements.allowShared = true; // allow because inBuf is used immediately
+    inBuf.reserve(requirements);
+    if (!inBuf.spaceSize())
+        debugs(33, 4, "request buffer full: client_request_buffer_max_size=" << Config.maxRequestBufferSize);
 }
 
 void
@@ -171,6 +167,7 @@ Server::doClientRead(const CommIoCbParams &io)
     // case Comm::COMM_ERROR:
     default: // no other flags should ever occur
         debugs(33, 2, io.conn << ": got flag " << rd.flag << "; " << xstrerr(rd.xerrno));
+        checkLogging();
         pipeline.terminateAll(rd.xerrno);
         io.conn->close();
         return;