From 38a4b6ab7bbd5e650f43541d091a52ed2655aff6 Mon Sep 17 00:00:00 2001
From: Ben Gamari <ben@smart-cactus.org>
Date: Wed, 6 Mar 2024 17:02:26 -0500
Subject: [PATCH] rts: Fix SET_HDR initialization of retainer set
This fixes a regression in retainer set profiling introduced by
b0293f78cb6acf2540389e22bdda420d0ab874da. Prior to that commit
the heap traversal word would be initialized by `SET_HDR` using
`LDV_RECORD_CREATE`. However, the commit added a `doingLDVProfiling`
check in `LDV_RECORD_CREATE`, meaning that this initialization no longer
happened.
Given that this initialization was awkwardly indirectly anyways, I have
fixed this by explicitly initializating the heap traversal word to
`NULL` in `SET_PROF_HDR`. This is equivalent to the previous behavior,
but much more direct.
Fixes #24513.
---
rts/include/rts/storage/ClosureMacros.h | 32 +++++++++----------------
1 file changed, 11 insertions(+), 21 deletions(-)
diff --git a/rts/include/rts/storage/ClosureMacros.h b/rts/include/rts/storage/ClosureMacros.h
index dbed34d490d6..b28f0d893f63 100644
--- a/rts/include/rts/storage/ClosureMacros.h
+++ b/rts/include/rts/storage/ClosureMacros.h
@@ -147,17 +147,10 @@ EXTERN_INLINE StgHalfWord GET_TAG(const StgClosure *con)
#if defined(PROFILING)
/*
The following macro works for both retainer profiling and LDV profiling. For
- retainer profiling, 'era' remains 0, so by setting the 'ldvw' field we also set
- 'rs' to zero.
-
- Note that we don't have to bother handling the 'flip' bit properly[1] since the
- retainer profiling code will just set 'rs' to NULL upon visiting a closure with
- an invalid 'flip' bit anyways.
-
- See Note [Profiling heap traversal visited bit] for details.
-
- [1]: Technically we should set 'rs' to `NULL | flip`.
+ retainer profiling, we set 'trav' to 0, which is an invalid
+ RetainerSet.
*/
+
/*
MP: Various other places use the check era > 0 to check whether LDV profiling
is enabled. The use of these predicates here is the reason for including RtsFlags.h in
@@ -168,17 +161,14 @@ EXTERN_INLINE StgHalfWord GET_TAG(const StgClosure *con)
*/
#define SET_PROF_HDR(c, ccs_) \
{ \
- (c)->header.prof.ccs = ccs_; \
- if (doingLDVProfiling()) { \
- LDV_RECORD_CREATE((c)); \
- } \
-\
- if (doingRetainerProfiling()) { \
- LDV_RECORD_CREATE((c)); \
- }; \
- if (doingErasProfiling()){ \
- ERA_RECORD_CREATE((c)); \
- }; \
+ (c)->header.prof.ccs = ccs_; \
+ if (doingLDVProfiling()) { \
+ LDV_RECORD_CREATE((c)); \
+ } else if (doingRetainerProfiling()) { \
+ (c)->header.prof.hp.trav = 0; \
+ } else if (doingErasProfiling()){ \
+ ERA_RECORD_CREATE((c)); \
+ } \
}
#else
--
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