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library: minimize the use of 'cleanup_stacks' routines

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Some parts of our newlib implementation are the result
of functions which have been propagated from module to
module. In particular, those 'cleanup_stacks' routines
are all similar & likely originated in the <pids> api.

In that interface there was a need to free dynamically
acquired memory before the result structure was reused
to satisfy subsequent 'get', 'select' or 'reap' calls.
This, in turn, led to a concept of 'dirty' stacks with
the need to call one of two 'cleanup_stack' functions.

None of the remaining interfaces deal with such memory
yet they each had their own 'cleanup_stack' functions.
Those functions were responsible for resetting each of
the result unions to zero, excluding any 'noop' items.

The bottom line is that for all interfaces, repetitive
calls would require iterating through the stack(s) two
separate times: once to 'cleanup' another to 'assign'.

With this commit we will reduce iterations to just the
'assign' routine. A reset to zero will be accomplished
in the 'extra' item set routine (which is the only one
actually requiring any reset). All other items will be
reinitialized automatically by a new current set value
or upon reallocation when an items compliment changes.

In the <pids> interface, any freeing of dynamic memory
could have been accomplished by adding that 'freefunc'
check to the 'assign' function. However, that requires
an Item_table test with every item. Instead, we'll now
satisfy such needs as the very first step in those set
functions responsible for dynamically acquired memory.

[ the <pids> api retains 2 'cleanup_stack' functions ]
[ to accommodate stack(s) 'reset' & to serve 'unref' ]

Lastly, all the 'itemize_stack' functions were tweaked
by eliminating an unnecessary initialization of result
unions. That objective was already accomplished by the
calloc() in a 'stacks_alloc' function or the remaining
'cleanup_stack' routine found in the <pids> interface.

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner
2019-05-22 00:00:00 -05:00
committed by Craig Small
parent 22a3bcbd6d
commit 40883a0b85
6 changed files with 33 additions and 221 deletions
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55
proc/pids.c
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@@ -78,7 +78,6 @@ struct pids_info {
struct fetch_support fetch; // support for procps_pids_reap & select
int history_yes; // need historical data
struct history_info *hist; // pointer to historical support data
int dirty_stacks; // stacks results need attention
proc_t*(*read_something)(PROCTAB*, proc_t*); // readproc/readeither via which
unsigned pgs2k_shift; // to convert some proc vaules
unsigned oldflags; // the old library PROC_FILL flagss
@@ -92,6 +91,19 @@ struct pids_info {
};
// ___ Free Storage Support |||||||||||||||||||||||||||||||||||||||||||||||||||
#define freNAME(t) free_pids_ ## t
static void freNAME(str) (struct pids_result *R) {
if (R->result.str) free(R->result.str);
}
static void freNAME(strv) (struct pids_result *R) {
if (R->result.strv && *R->result.strv) free(*R->result.strv);
}
// ___ Results 'Set' Support ||||||||||||||||||||||||||||||||||||||||||||||||||
#define setNAME(e) set_pids_ ## e
@@ -103,6 +115,7 @@ struct pids_info {
R->result. t = (long)(P-> x) << I -> pgs2k_shift; }
/* strdup of a static char array */
#define DUP_set(e,x) setDECL(e) { \
freNAME(str)(R); \
if (!(R->result.str = strdup(P-> x))) I->seterr = 1; }
/* regular assignment copy */
#define REG_set(e,t,x) setDECL(e) { \
@@ -110,19 +123,22 @@ struct pids_info {
/* take ownership of a normal single string if possible, else return
some sort of hint that they duplicated this char * item ... */
#define STR_set(e,x) setDECL(e) { \
freNAME(str)(R); \
if (NULL != P-> x) { R->result.str = P-> x; P-> x = NULL; } \
else { R->result.str = strdup("[ duplicate " STRINGIFY(e) " ]"); \
if (!R->result.str) I->seterr = 1; } }
/* take ownership of true vectorized strings if possible, else return
some sort of hint that they duplicated this char ** item ... */
#define VEC_set(e,x) setDECL(e) { \
freNAME(strv)(R); \
if (NULL != P-> x) { R->result.strv = P-> x; P-> x = NULL; } \
else { R->result.strv = vectorize_this_str("[ duplicate " STRINGIFY(e) " ]"); \
if (!R->result.str) I->seterr = 1; } }
setDECL(noop) { (void)I; (void)R; (void)P; return; }
setDECL(extra) { (void)I; (void)R; (void)P; return; }
setDECL(noop) { (void)I; (void)R; (void)P; }
setDECL(extra) { (void)I; (void)P; R->result.ull_int = 0; }
REG_set(ADDR_END_CODE, ul_int, end_code)
REG_set(ADDR_KSTK_EIP, ul_int, kstk_eip)
REG_set(ADDR_KSTK_ESP, ul_int, kstk_esp)
@@ -226,8 +242,8 @@ setDECL(TIME_ALL) { R->result.ull_int = (P->utime + P->stime) / I->hertz;
setDECL(TIME_ELAPSED) { unsigned long long t = P->start_time / I->hertz; R->result.ull_int = I->boot_seconds >= t ? (I->boot_seconds - t) : 0; }
REG_set(TIME_START, ull_int, start_time)
REG_set(TTY, s_int, tty)
setDECL(TTY_NAME) { char buf[64]; dev_to_tty(buf, sizeof(buf), P->tty, P->tid, ABBREV_DEV); if (!(R->result.str = strdup(buf))) I->seterr = 1; }
setDECL(TTY_NUMBER) { char buf[64]; dev_to_tty(buf, sizeof(buf), P->tty, P->tid, ABBREV_DEV|ABBREV_TTY|ABBREV_PTS); if (!(R->result.str = strdup(buf))) I->seterr = 1; }
setDECL(TTY_NAME) { char buf[64]; freNAME(str)(R); dev_to_tty(buf, sizeof(buf), P->tty, P->tid, ABBREV_DEV); if (!(R->result.str = strdup(buf))) I->seterr = 1; }
setDECL(TTY_NUMBER) { char buf[64]; freNAME(str)(R); dev_to_tty(buf, sizeof(buf), P->tty, P->tid, ABBREV_DEV|ABBREV_TTY|ABBREV_PTS); if (!(R->result.str = strdup(buf))) I->seterr = 1; }
REG_set(VM_DATA, ul_int, vm_data)
REG_set(VM_EXE, ul_int, vm_exe)
REG_set(VM_LIB, ul_int, vm_lib)
@@ -241,7 +257,7 @@ REG_set(VM_STACK, ul_int, vm_stack)
REG_set(VM_SWAP, ul_int, vm_swap)
setDECL(VM_USED) { (void)I; R->result.ul_int = P->vm_swap + P->vm_rss; }
REG_set(VSIZE_PGS, ul_int, vsize)
setDECL(WCHAN_NAME) { if (!(R->result.str = strdup(lookup_wchan(P->tid)))) I->seterr = 1;; }
setDECL(WCHAN_NAME) { freNAME(str)(R); if (!(R->result.str = strdup(lookup_wchan(P->tid)))) I->seterr = 1;; }
#undef setDECL
#undef CVT_set
@@ -251,19 +267,6 @@ setDECL(WCHAN_NAME) { if (!(R->result.str = strdup(lookup_wchan(P->tid)))) I
#undef VEC_set
// ___ Free Storage Support |||||||||||||||||||||||||||||||||||||||||||||||||||
#define freNAME(t) free_pids_ ## t
static void freNAME(str) (struct pids_result *R) {
if (R->result.str) free(R->result.str);
}
static void freNAME(strv) (struct pids_result *R) {
if (R->result.strv && *R->result.strv) free(*R->result.strv);
}
// ___ Sorting Support ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
struct sort_parms {
@@ -777,8 +780,7 @@ static inline void pids_cleanup_stack (
break;
if (Item_table[item].freefunc)
Item_table[item].freefunc(this);
if (item > PIDS_noop)
this->result.ull_int = 0;
this->result.ull_int = 0;
++this;
}
} // end: pids_cleanup_stack
@@ -795,7 +797,6 @@ static inline void pids_cleanup_stacks_all (
pids_cleanup_stack(ext->stacks[i]->head);
ext = ext->next;
};
info->dirty_stacks = 0;
} // end: pids_cleanup_stacks_all
@@ -836,7 +837,6 @@ static inline struct pids_result *pids_itemize_stack (
for (i = 0; i < depth; i++) {
p->item = items[i];
p->result.ull_int = 0;
++p;
}
return p_sav;
@@ -854,7 +854,6 @@ static void pids_itemize_stacks_all (
pids_itemize_stack(ext->stacks[i]->head, info->curitems, info->items);
ext = ext->next;
};
info->dirty_stacks = 0;
} // end: pids_itemize_stacks_all
@@ -1052,7 +1051,6 @@ static int pids_stacks_fetch (
memcpy(info->fetch.anchor, ext->stacks, sizeof(void *) * STACKS_INCR);
n_alloc = STACKS_INCR;
}
pids_cleanup_stacks_all(info);
pids_toggle_history(info);
memset(&info->fetch.counts, 0, sizeof(struct pids_counts));
@@ -1089,7 +1087,6 @@ static int pids_stacks_fetch (
}
memcpy(info->fetch.results.stacks, info->fetch.anchor, sizeof(void *) * n_inuse);
info->fetch.results.stacks[n_inuse] = NULL;
info->dirty_stacks = 1;
return n_inuse; // callers beware, this might be zero !
#undef n_alloc
@@ -1304,8 +1301,6 @@ fresh_start:
}
errno = 0;
pids_cleanup_stack(info->get_ext->stacks[0]->head);
if (NULL == info->read_something(info->get_PT, &task))
return NULL;
if (!pids_assign_results(info, info->get_ext->stacks[0], &task))
@@ -1360,8 +1355,7 @@ PROCPS_EXPORT int procps_pids_reset (
if (pids_items_check_failed(newitems, newnumitems))
return -EINVAL;
if (info->dirty_stacks)
pids_cleanup_stacks_all(info);
pids_cleanup_stacks_all(info);
/* shame on this caller, they didn't change anything. and unless they have
altered the depth of the stacks we're not gonna change anything either! */
@@ -1394,6 +1388,7 @@ PROCPS_EXPORT int procps_pids_reset (
// account for above PIDS_logical_end
info->curitems = newnumitems + 1;
// if extents freed above, pids_stacks_alloc() will itemize ...
pids_itemize_stacks_all(info);
pids_libflags_set(info);