[PATCH] kconfig: Fix Kconfig performance bug (3f04e7dd) · Commits · 戴 / test

When doing its recursive dependency check, scripts/kconfig/conf uses the flag SYMBOL_CHECK_DONE to avoid rechecking a symbol it has already checked. However, that flag is only set at the top level, so if a symbol is first encountered as a dependency of another symbol it will be rechecked every time it is encountered until it's encountered at the top level. This patch adjusts the flag setting so that each symbol will only be checked once, regardless of whether it is first encountered at the top level, or while recursing down from another symbol. On complex configurations, this vastly speeds up scripts/kconfig/conf. The config in the powerpc merge tree is particularly bad: this patch reduces the time for 'scripts/kconfig/conf -o arch/powerpc/Kconfig' by a factor of 40 on a G5. That's even including the time to print the config, so the speedup in the actual checking is more likely 2 or 3 orders of magnitude. Signed-off-by:

David Gibson <david@gibson.dropbear.id.au> Signed-off-by:

Roman Zippel <zippel@linux-m68k.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

scripts/kconfig/expr.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -93,7 +93,6 @@ struct symbol {
		#define SYMBOL_NEW 0x0800
		#define SYMBOL_AUTO 0x1000
		#define SYMBOL_CHECKED 0x2000
		#define SYMBOL_CHECK_DONE 0x4000
		#define SYMBOL_WARNED 0x8000

		#define SYMBOL_MAXLENGTH 256

scripts/kconfig/symbol.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -731,12 +731,12 @@ struct symbol sym_check_deps(struct symbol sym)
		struct symbol *sym2;
		struct property *prop;

		if (sym->flags & SYMBOL_CHECK_DONE)
		return NULL;
		if (sym->flags & SYMBOL_CHECK) {
		printf("Warning! Found recursive dependency: %s", sym->name);
		return sym;
		}
		if (sym->flags & SYMBOL_CHECKED)
		return NULL;

		sym->flags \|= (SYMBOL_CHECK \| SYMBOL_CHECKED);
		sym2 = sym_check_expr_deps(sym->rev_dep.expr);
		@@ -756,8 +756,13 @@ struct symbol sym_check_deps(struct symbol sym)
		goto out;
		}
		out:
		if (sym2)
		if (sym2) {
		printf(" %s", sym->name);
		if (sym2 == sym) {
		printf("\n");
		sym2 = NULL;
		}
		}
		sym->flags &= ~SYMBOL_CHECK;
		return sym2;
		}

scripts/kconfig/zconf.tab.c_shipped

+1 −4

Original line number	Diff line number	Diff line
		@@ -1933,10 +1933,7 @@ void conf_parse(const char *name)
		exit(1);
		menu_finalize(&rootmenu);
		for_all_symbols(i, sym) {
		if (!(sym->flags & SYMBOL_CHECKED) && sym_check_deps(sym))
		printf("\n");
		else
		sym->flags \|= SYMBOL_CHECK_DONE;
		sym_check_deps(sym);
		}

		sym_change_count = 1;

scripts/kconfig/zconf.y

+1 −4

Original line number	Diff line number	Diff line
		@@ -495,10 +495,7 @@ void conf_parse(const char *name)
		exit(1);
		menu_finalize(&rootmenu);
		for_all_symbols(i, sym) {
		if (!(sym->flags & SYMBOL_CHECKED) && sym_check_deps(sym))
		printf("\n");
		else
		sym->flags \|= SYMBOL_CHECK_DONE;
		sym_check_deps(sym);
		}

		sym_change_count = 1;

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