On 21/07/2012 11:06 a.m., Alex Rousskov wrote:
On 07/19/2012 08:40 PM, Amos Jeffries wrote:
On 20/07/2012 12:34 p.m., Alex Rousskov wrote:
Hello,
I believe the current trunk is profusely leaking memory. There may
be several reasons, but my current suspect is a circular RefCounted
reference that allows neither HttpRequest nor AccessLogEntry to be freed:
HttpRequest -> AccessLogEntry -> HttpRequest
The circle was created by the request_header_add feature during the
review process, when it was decided that we should reuse the Format API
to expand macros in the added header values. That API needs
AccessLogEntry. This is good news -- there is not much code relying on
the circle existence!
The bad news is that breaking the circle is not trivial. Copying
AccessLogEntry to HttpRequest (instead of linking the two) is not a good
option because the AccessLogEntry object needs to be populated with
values collected throughout the master transaction lifetime -- up until
httpHdrAdd() is called on the server side (and much later when we start
supporting macros in mangled responses).
However, when the transaction reaches termination and logging is
completed it becomes no longer useful (next transaction must re-fill
with new details specific to that transaction).
A clear() method on the entry would be good for resetting all its
pointers after logging completion.
The mess stems from the fact that AccessLogEntry is not generally
available on the server side. HttpRequest is available there but it
cannot be used for AccessLogEntry smuggling (due to the above loop).
Unless I hear better ideas, I will extend the FwdState::fwdStart() API
to supply an AccessLogEntry (and store it in Server/etc). This may even
help with future plans of converting ALE into some kind of MasterXaction
class.
Both would be good loong-term, but up to you which gets chosen. I'm
inclined to leave the API changes until xaction project can be started
properly.
Attached is the patch implementing those API changes. They are minor,
and I even kept the old fwdStart() call so that fewer files like Asn.cc
and htcp.cc have to be modified and exposed to AccessLogEntry.h. These
changes give AccessLogEntry to the server side, but this is only a tiny
step towards supporting a true MasterXact object.
The patch removes HttpRequest::al member, breaking the refcounting loop.
Squid does not seem to leak with these changes.
Any objections to this patch going into trunk?
+1. Looks fine.
Amos
