From 788675b0916e4f26853cd31d1841b29a04bd3ccd Mon Sep 17 00:00:00 2001
From: normalcoder <normalcoder@gmail.com>
Date: Sun, 19 Dec 2021 20:39:35 +0300
Subject: [PATCH] Add arbitraryHeapStart flag. It allows to allocate the memory
block anywhere, not only above the 8 GB. Without it we can get an inifite
loop in osReserveHeapMemory because ios sometimes doesn't allocate memory
below the 8 GB
---
libraries/base/src/GHC/RTS/Flags.hsc | 3 +++
rts/RtsFlags.c | 6 ++++++
rts/include/rts/Flags.h | 1 +
rts/posix/OSMem.c | 4 +++-
4 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/libraries/base/src/GHC/RTS/Flags.hsc b/libraries/base/src/GHC/RTS/Flags.hsc
index 2424a4f2c439..0999dcbfcf9d 100644
--- a/libraries/base/src/GHC/RTS/Flags.hsc
+++ b/libraries/base/src/GHC/RTS/Flags.hsc
@@ -144,6 +144,7 @@ data GCFlags = GCFlags
, minOldGenSize :: Word32
, heapSizeSuggestion :: Word32
, heapSizeSuggestionAuto :: Bool
+ , arbitraryHeapStart :: Bool
, oldGenFactor :: Double
, returnDecayFactor :: Double
, pcFreeHeap :: Double
@@ -462,6 +463,8 @@ getGCFlags = do
<*> #{peek GC_FLAGS, heapSizeSuggestion} ptr
<*> (toBool <$>
(#{peek GC_FLAGS, heapSizeSuggestionAuto} ptr :: IO CBool))
+ <*> (toBool <$>
+ (#{peek GC_FLAGS, arbitraryHeapStart} ptr :: IO CBool))
<*> #{peek GC_FLAGS, oldGenFactor} ptr
<*> #{peek GC_FLAGS, returnDecayFactor} ptr
<*> #{peek GC_FLAGS, pcFreeHeap} ptr
diff --git a/rts/RtsFlags.c b/rts/RtsFlags.c
index 8c384ad43272..6e841d838f9f 100644
--- a/rts/RtsFlags.c
+++ b/rts/RtsFlags.c
@@ -162,6 +162,7 @@ void initRtsFlagsDefaults(void)
RtsFlags.GcFlags.heapLimitGrace = (1024 * 1024);
RtsFlags.GcFlags.heapSizeSuggestion = 0; /* none */
RtsFlags.GcFlags.heapSizeSuggestionAuto = false;
+ RtsFlags.GcFlags.arbitraryHeapStart = false;
RtsFlags.GcFlags.pcFreeHeap = 3; /* 3% */
RtsFlags.GcFlags.oldGenFactor = 2;
RtsFlags.GcFlags.returnDecayFactor = 4;
@@ -1055,6 +1056,11 @@ error = true;
OPTION_UNSAFE;
RtsFlags.HpcFlags.writeTixFile = false;
}
+ else if (strequal("arbitrary-heap-start",
+ &rts_argv[arg][2])) {
+ OPTION_UNSAFE;
+ RtsFlags.GcFlags.arbitraryHeapStart = true;
+ }
#if defined(THREADED_RTS)
#if defined(mingw32_HOST_OS)
else if (!strncmp("io-manager-threads",
diff --git a/rts/include/rts/Flags.h b/rts/include/rts/Flags.h
index e4405463311d..5ef7273aace5 100644
--- a/rts/include/rts/Flags.h
+++ b/rts/include/rts/Flags.h
@@ -49,6 +49,7 @@ typedef struct _GC_FLAGS {
uint32_t minOldGenSize; /* in *blocks* */
uint32_t heapSizeSuggestion; /* in *blocks* */
bool heapSizeSuggestionAuto;
+ bool arbitraryHeapStart;
double oldGenFactor;
double returnDecayFactor;
double pcFreeHeap;
diff --git a/rts/posix/OSMem.c b/rts/posix/OSMem.c
index a6eabfcdeedc..c9ad67d2a725 100644
--- a/rts/posix/OSMem.c
+++ b/rts/posix/OSMem.c
@@ -608,9 +608,11 @@ void *osReserveHeapMemory(void *startAddressPtr, W_ *len)
// physical memory but a 511GB ulimit). See #14492.
*len -= *len / 8;
// debugBelch("Limit hit, reduced len: %zu\n", *len);
- } else if ((W_)at >= minimumAddress) {
+ } else if (RtsFlags.GcFlags.arbitraryHeapStart || (W_)at >= minimumAddress) {
// Success! We were given a block of memory starting above the 8 GB
// mark, which is what we were looking for.
+ // Or we allow to allocate the block anywhere by setting
+ // arbitraryHeapStart flag.
break;
} else {
--
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