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top: implement a new approach to forest view mode

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The TREE_RESCANS #define (formerly TREE_ONEPASS) has
been eliminated and the approach to forest view mode
redesigned.  The chance of dangling children has been
eliminated and overhead reduced.

We now order processes on start_time (non-display)
and are therefore immune to any pid, ppid or tgid
anomalies when pid values wrap.

The new algorithm also accommodates any distortions
caused by the 3.3 kernel 'hidepid' provisions --
something guaranteed to produce dangling children
under the former approach.

Related References:
commit a2086dfdf6
commit cd608f462e
commit 41ed28aa5d

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2012-08-25 23:59:59 -05:00 committed by Craig Small
parent d9890fb5ac
commit beb0982b28
2 changed files with 28 additions and 24 deletions
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48
top/top.c
View File

@ -1437,8 +1437,8 @@ static void build_headers (void) {
if (Screen_cols > (int)strlen(w->columnhdr)) w->eolcap = Caps_endline;
else w->eolcap = Caps_off;
#endif
// with forest view mode, we'll need tgid & ppid...
if (CHKw(w, Show_FOREST)) Frames_libflags |= L_status;
// with forest view mode, we'll need tgid, ppid & start_time...
if (CHKw(w, Show_FOREST)) Frames_libflags |= (L_status | L_stat);
// for 'busy' only processes, we'll need pcpu (utime & stime)...
if (!CHKw(w, Show_IDLEPS)) Frames_libflags |= L_stat;
// we must also accommodate an out of view sort field...
@ -3396,7 +3396,10 @@ static void keys_xtra (int ch) {
/*###### Forest View support ###########################################*/
/*
* We try to keep most existing code unaware of our activities. */
* We try to keep most existing code unaware of our activities
* ( plus, maintain alphabetical order with carefully chosen )
* ( function names: forest_a, forest_b, forest_c & forest_d )
* ( each with exactly one letter more than its predecessor! ) */
static proc_t **Seed_ppt; // temporary window ppt ptr
static proc_t **Tree_ppt; // resized by forest_create
static int Tree_idx; // frame_make initializes
@ -3405,22 +3408,28 @@ static int Tree_idx; // frame_make initializes
* This little recursive guy is the real forest view workhorse.
* He fills in the Tree_ppt array and also sets the child indent
* level which is stored in an unused proc_t padding byte. */
static void forest_add (const int self, const int level) {
static void forest_adds (const int self, const int level) {
int i;
Tree_ppt[Tree_idx] = Seed_ppt[self]; // add this as root or child
Tree_ppt[Tree_idx++]->pad_3 = level; // borrow 1 byte, 127 levels
#ifdef TREE_RESCANS
for (i = 0; i < Frame_maxtask; i++) { // this is hardly bullet proof now,
if (i == self) continue; // with 3.3 proc hidepid provisions
#else
for (i = self + 1; i < Frame_maxtask; i++) {
#endif
if (Seed_ppt[self]->tid == Seed_ppt[i]->tgid
|| (Seed_ppt[self]->tid == Seed_ppt[i]->ppid && Seed_ppt[i]->tid == Seed_ppt[i]->tgid))
forest_add(i, level + 1); // got one child any others?
forest_adds(i, level + 1); // got one child any others?
}
} // end: forest_add
} // end: forest_adds
/*
* Our qsort callback to order a ppt by the non-display start_time
* which will make us immune from any pid, ppid or tgid anomalies
* if/when pid values are wrapped by the kernel! */
static int forest_based (const proc_t **x, const proc_t **y) {
if ( (*x)->start_time > (*y)->start_time ) return 1;
if ( (*x)->start_time < (*y)->start_time ) return -1;
return 0;
} // end: forest_based
/*
@ -3430,22 +3439,18 @@ static void forest_add (const int self, const int level) {
* ordered forest version. */
static void forest_create (WIN_t *q) {
static int hwmsav;
int i;
Seed_ppt = q->ppt; // avoid passing WIN_t ptrs
if (!Tree_idx) { // do just once per frame
int i = 0;
Frame_srtflg = -1; // put in ascending ppid order
qsort(Seed_ppt, Frame_maxtask, sizeof(proc_t*), Fieldstab[P_PPD].sort);
if (hwmsav < Frame_maxtask) { // grow, but never shrink
hwmsav = Frame_maxtask;
Tree_ppt = alloc_r(Tree_ppt, sizeof(proc_t*) * hwmsav);
}
while (0 == Seed_ppt[i]->ppid) // identify trees (expect 2)
forest_add(i++, 1); // add parent plus children
if (Tree_idx != Frame_maxtask) // this will keep us sane...
for (i = 0; i < Frame_maxtask; i++)
if (!Seed_ppt[i]->pad_3)
Tree_ppt[Tree_idx++] = Seed_ppt[i];
qsort(Seed_ppt, Frame_maxtask, sizeof(proc_t*), (QFP_t)forest_based);
for (i = 0; i < Frame_maxtask; i++) // avoid any hidepid distortions
if (!Seed_ppt[i]->pad_3) // identify real or pretend trees
forest_adds(i, 1); // add as parent plus its children
}
memcpy(Seed_ppt, Tree_ppt, sizeof(proc_t*) * Frame_maxtask);
} // end: forest_create
@ -3463,8 +3468,7 @@ static inline const char *forest_display (const WIN_t *q, const proc_t *p) {
const char *which = (CHKw(q, Show_CMDLIN)) ? *p->cmdline : p->cmd;
if (!CHKw(q, Show_FOREST) || 1 == p->pad_3) return which;
if (!p->pad_3) snprintf(buf, sizeof(buf), " ? %s", which);
else snprintf(buf, sizeof(buf), "%*s%s", 4 * (p->pad_3 - 1), " `- ", which);
snprintf(buf, sizeof(buf), "%*s%s", 4 * (p->pad_3 - 1), " `- ", which);
return buf;
} // end: forest_display

4
top/top.h
View File

@ -43,7 +43,6 @@
//#define STRINGCASENO /* case insenstive compare/locate versions */
//#define TERMIO_PROXY /* true line editing, beyond native input */
//#define TREE_NORESET /* sort keys do NOT force forest view OFF */
//#define TREE_RESCANS /* restart scan to avoid dangling children */
//#define USE_X_COLHDR /* emphasize header vs. whole col, for 'x' */
//#define VALIDATE_NLS /* validate integrity of all 3 nls tables */
//#define WARN_CFG_OFF /* warning OFF when overwriting old rcfile */
@ -650,7 +649,8 @@ typedef struct WIN_t {
//atic void keys_window (int ch);
//atic void keys_xtra (int ch);
/*------ Forest View support -------------------------------------------*/
//atic void forest_add (const int self, const int level);
//atic void forest_adds (const int self, const int level);
//atic int forest_based (const proc_t **x, const proc_t **y);
//atic void forest_create (WIN_t *q);
//atic inline const char *forest_display (const WIN_t *q, const proc_t *p);
/*------ Main Screen routines ------------------------------------------*/