diff options
Diffstat (limited to 'sys/nmemio/mgc.x')
| -rw-r--r-- | sys/nmemio/mgc.x | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/sys/nmemio/mgc.x b/sys/nmemio/mgc.x new file mode 100644 index 00000000..8ef2b58c --- /dev/null +++ b/sys/nmemio/mgc.x @@ -0,0 +1,222 @@ +# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc. + +include <mach.h> + + +# MGC Interface - Simple memory garbage collector interface. Our strategy +# here is simply to store the pointer and its type (so we can dereference to +# a host pointer). As pointers are allocated they are saved here, and when +# freed the pointer value is made negative to indicate it is invalid and +# that slot is available for later reuse. +# When a task completes, we run through the buffer looking for un-freed +# pointers and manually reclaim the space. This is not especially clever but +# we are only used (presumably by developers) when requested so normal use +# of MEMIO should see no added overhead. +# +# mgc_init () +# mgc_close () +# mgc_save (ptr, dtype) +# mgc_update (ptr) +# index = mgc_getindex (ptr) +# type = mgc_gettype (ptr) +# mgc_collect () + + +define SZ_GC_BUFFER 10240 + +# A zero-indexed structure saving the (ptr,type) pairs. +define GC_PTR Memi[$1+($2 * 2)] +define GC_TYPE Memi[$1+($2 * 2 + 1)] + + +# MGC_INIT -- Initialize the MGC interface. + +procedure mgc_init () + +include "nmemio.com" + +begin + if (mcollect > 0) + call calloc (mgc, SZ_GC_BUFFER, TY_STRUCT) + else + mgc = NULL +end + + +# MGC_CLOSE -- Close the MGC buffer. + +procedure mgc_close () + +include "nmemio.com" + +begin + if (mcollect > 0 && mgc != NULL) { + call mfree (mgc, TY_STRUCT) + mgc = NULL + } +end + + +# MGC_SAVE -- Save a pointer in the GC buffer. + +procedure mgc_save (ptr, dtype) + +pointer ptr #i pointer to save +int dtype #i pointer type + +int i, bmax + +include "nmemio.com" + +begin + if (mcollect <= 0 || mgc == NULL) + return + + bmax = SZ_GC_BUFFER - 1 + for (i=0; i < bmax; i=i+1) { + if (GC_PTR(mgc,i) <= 0) { + # Space is re-used if negative, otherwise first free slot. + GC_PTR(mgc,i) = ptr + GC_TYPE(mgc,i) = dtype + + if (mdebug > 0) { + call eprintf ("save %d: ptr 0x%x\n") + call pargi (i); call pargi (GC_PTR(mgc,i)) + } + return + } + } + + # If we get this far we've exhausted the GC buffer. Print a warning + # if reporting and just ignore it since the chances this would be + # a leaked pointer are rather small. + if (mreport > 0) + call eprintf ("Warning: GC buffer overflow\n") +end + + +# MGC_UPDATE -- Update the status of the pointer in the GC buffer. + +procedure mgc_update (ptr) + +pointer ptr #i pointer to save + +int i, bmax + +include "nmemio.com" + +begin + if (mgc == NULL || in_task == 0) + return + + if (in_task > 0 && mdebug > 0) { + call eprintf ("update 0x%x collect = %d\n") + call pargi (ptr) + call pargi (mcollect) + } + + bmax = SZ_GC_BUFFER - 1 + do i = 0, bmax { + if (GC_PTR(mgc,i) == ptr) { + if (in_task > 0 && mdebug > 0) { + call eprintf ("update %d: 0x%x %d\n") + call pargi (i); call pargi (GC_PTR(mgc,i)); call pargi (ptr) + } + GC_PTR(mgc,i) = (- ptr) + return + } + if (GC_PTR(mgc,i) == NULL) + return + } +end + + +# MGC_GETINDEX -- Given a pointer, return its GC index. + +int procedure mgc_getindex (ptr) + +pointer ptr #i pointer to save + +int i, bmax + +include "nmemio.com" + +begin + if (mcollect <= 0 || mgc == NULL) + return + + bmax = SZ_GC_BUFFER - 1 + do i = 0, bmax { + if (abs (GC_PTR(mgc,i)) == ptr) + return (i) + if (GC_PTR(mgc,i) == NULL) + return (NULL) + } + + return (NULL) +end + + +# MGC_GETTYPE -- Given a pointer, return its type. + +int procedure mgc_gettype (ptr) + +pointer ptr #i pointer to save + +int i, bmax + +include "nmemio.com" + +begin + if (mcollect <= 0 || mgc == NULL) + return + + bmax = SZ_GC_BUFFER - 1 + do i = 0, bmax { + if (abs (GC_PTR(mgc,i)) == ptr) + return (GC_TYPE(mgc,i)) + if (GC_PTR(mgc,i) == NULL) + return (NULL) + } + + return (NULL) +end + + +# MGC_COLLECT -- Do the final garbage collection. + +procedure mgc_collect () + +int i, bmax, nchars +pointer bp + +int sizeof () +pointer coerce () + +include "nmemio.com" + +begin + if (mcollect <= 0 || mgc == NULL) + return + mcollect = -1 + + bmax = SZ_GC_BUFFER - 1 + do i = 0, bmax { + if (GC_PTR(mgc,i) > 0) { + if (mdebug > 0) { + call eprintf ("collect %d: recovering ptr 0x%x\n") + call pargi (i); call pargi (GC_PTR(mgc,i)) + } + + bp = coerce (GC_PTR(mgc,i), GC_TYPE(mgc,i), TY_INT) + + nleaked = nleaked + 1 + nchars = Memi[bp - 2] * sizeof (GC_TYPE(mgc,i)) + leaked = leaked + (nchars * SZB_CHAR) + + call mfree (GC_PTR(mgc,i), GC_TYPE(mgc,i)) + + } else if (GC_PTR(mgc,i) == NULL) + return + } +end |