From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 225AEC3600C for ; Mon, 24 Mar 2025 15:08:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 99D1C10E42B; Mon, 24 Mar 2025 15:08:22 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=bootlin.com header.i=@bootlin.com header.b="BgW/Llt4"; dkim-atps=neutral Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) by gabe.freedesktop.org (Postfix) with ESMTPS id 56F3310E423; Mon, 24 Mar 2025 15:08:20 +0000 (UTC) Received: by mail.gandi.net (Postfix) with ESMTPSA id 0F1A84425B; Mon, 24 Mar 2025 15:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1742828899; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=B8WCvbcBG/swgTDjytmb4iTiToSMWuDyajHh9/+5uRA=; b=BgW/Llt4dzW79LVS2TbrGvbmEp76JjglpnGYmzXu0z9lS0b/E/Pq8X8g6k8v3BYtnOO4R0 prmr+XRgMaL9fu8Ev5QR9NmGk/9s0sAHY5yCCziAGD7nq8K9frYeA0JWMwyeWZEWXRUwXr k1y3erl8PZNK53nsFIEagvQVK2lnMRhASprcyfAIyXt/SwtWE+yJYdsvn8dHuZsLJAuaBT CbWv0cUXszGqboeDfGWNAoU47aSzfRvgLv9gPaLATY9vf8D8wePDL32cjuXc+WbPS8IxVb vm/9VBFsohnAGaDNzbfyqNn0ePTXqUOTh173nnPnva8CZyLLuz/feuWRMLx+GQ== Message-ID: Date: Mon, 24 Mar 2025 16:08:13 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Louis Chauvet Subject: Re: [PATCH v2 10/59] dyndbg: replace classmap list with a vector To: Jim Cromie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-gfx-trybot@lists.freedesktop.org Cc: jbaron@akamai.com, gregkh@linuxfoundation.org, ukaszb@chromium.org, daniel.vetter@ffwll.ch, tvrtko.ursulin@linux.intel.com, jani.nikula@intel.com, ville.syrjala@linux.intel.com References: <20250320185238.447458-1-jim.cromie@gmail.com> <20250320185238.447458-11-jim.cromie@gmail.com> Content-Language: en-US Autocrypt: addr=louis.chauvet@bootlin.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdduiedttdelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefkffggfgfhuffvvehfjggtgfesthekredttddvjeenucfhrhhomhepnfhouhhishcuvehhrghuvhgvthcuoehlohhuihhsrdgthhgruhhvvghtsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeetfffhtdeigfehffduuedvkeefgfdvuddugfffteetffdvteffgfejvedugffgffenucffohhmrghinhepsghoohhtlhhinhdrtghomhenucfkphepledtrdekledrudeifedruddvjeenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeeltddrkeelrdduieefrdduvdejpdhhvghloheplgduledvrdduieekrddtrddvtdgnpdhmrghilhhfrhhomheplhhouhhishdrtghhrghuvhgvthessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepudegpdhrtghpthhtohepjhhimhdrtghrohhmihgvsehgmhgrihhlrdgtohhmpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepughrihdquggvvhgvlheslhhishhtshdrfhhrvggvuggvshhkthhophdrohhrghdprhgtphhtthhopegrmhguqdhgfhigsehlihhsthhsr dhfrhgvvgguvghskhhtohhprdhorhhgpdhrtghpthhtohepihhnthgvlhdqghhvthdquggvvheslhhishhtshdrfhhrvggvuggvshhkthhophdrohhrghdprhgtphhtthhopehinhhtvghlqdhgfhigsehlihhsthhsrdhfrhgvvgguvghskhhtohhprdhorhhgpdhrtghpthhtohepihhnthgvlhdqghhfgidqthhrhigsohhtsehlihhsthhsrdhfrhgvvgguvghskhhtohhprdhorhhgpdhrtghpthhtohepjhgsrghrohhnsegrkhgrmhgrihdrtghomh X-GND-Sasl: louis.chauvet@bootlin.com X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Le 20/03/2025 à 19:51, Jim Cromie a écrit : > Classmaps are stored in an elf section/array, but currently are > individually list-linked onto dyndbg's per-module ddebug_table for > operation. This is unnecessary. > > Just like dyndbg's descriptors, classes are packed in compile order; > so even with many builtin modules employing multiple classmaps, each > modules' maps are packed contiguously, and can be treated as a > array-start-address & array-length. > > So this drops the whole list building operation done in > ddebug_attach_module_classes(), and removes the list-head members. > The "select-by-modname" condition is reused to find the start,end of > the subrange. > > NOTE: This "filter-by-modname" on classmaps should really be done in > ddebug_add_module(1); ie at least one step closer to ddebug_init(2), > which already splits up pr-debug descriptors into subranges by > modname, then calls (1) on each. (2) knows nothing of classmaps > currently, and doesn't need to. For now, just add comment. > > Signed-off-by: Jim Cromie > --- > include/linux/dynamic_debug.h | 1 - > lib/dynamic_debug.c | 61 ++++++++++++++++++----------------- > 2 files changed, 32 insertions(+), 30 deletions(-) > > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h > index ac199293d203..e458d4b838ac 100644 > --- a/include/linux/dynamic_debug.h > +++ b/include/linux/dynamic_debug.h > @@ -83,7 +83,6 @@ enum class_map_type { > }; > > struct ddebug_class_map { > - struct list_head link; > struct module *mod; > const char *mod_name; /* needed for builtins */ > const char **class_names; > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c > index dd7320b9616d..d5572712ce55 100644 > --- a/lib/dynamic_debug.c > +++ b/lib/dynamic_debug.c > @@ -45,10 +45,11 @@ extern struct ddebug_class_map __start___dyndbg_classes[]; > extern struct ddebug_class_map __stop___dyndbg_classes[]; > > struct ddebug_table { > - struct list_head link, maps; > + struct list_head link; > const char *mod_name; > - unsigned int num_ddebugs; > struct _ddebug *ddebugs; > + struct ddebug_class_map *classes; > + unsigned int num_ddebugs, num_classes; > }; > > struct ddebug_query { > @@ -147,13 +148,15 @@ static void vpr_info_dq(const struct ddebug_query *query, const char *msg) > query->first_lineno, query->last_lineno, query->class_string); > } > > +#define __outvar /* filled by callee */ > static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table const *dt, > - const char *class_string, int *class_id) > + const char *class_string, > + __outvar int *class_id) Thanks for your explanation of __outvar! It makes sense. I never seen this pattern anywhere in the kernel, maybe a simple doc comment is enough to carry the information: /** * ddebug_find_valid_class - Find a valid class for a * given string * @dt: debug table to inspect * @class_string: string to match on * @class_id: output pointer for the class_id value * * Returns: Pointer to the ddebug_class_map instance, if found. * @class_id will be set to the id of this class. If no class * matching @class_string is found, returns NULL and class_id is * set to -ENOENT. */ Or at maybe change the documentation of __outvar to be a bit more explicit about how it works (I had difficulties to understand because a lot of "magic macro" exist in the kernel and sometimes carry information to the compiler, but this one is always empty): /** * __outvar - Denotes that an argument is used as an output * value * This macro does nothing apart clarify for the reader that * the parameter will be filled by the callee */ With any of the modifications (feel free to reword them as you want): Reviewed-by: Louis Chauvet > { > struct ddebug_class_map *map; > - int idx; > + int i, idx; > > - list_for_each_entry(map, &dt->maps, link) { > + for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) { > idx = match_string(map->class_names, map->length, class_string); > if (idx >= 0) { > *class_id = idx + map->base; > @@ -164,7 +167,6 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons > return NULL; > } > > -#define __outvar /* filled by callee */ > /* > * Search the tables for _ddebug's which match the given `query' and > * apply the `flags' and `mask' to them. Returns number of matching > @@ -1122,9 +1124,10 @@ static void *ddebug_proc_next(struct seq_file *m, void *p, loff_t *pos) > > static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp) > { > - struct ddebug_class_map *map; > + struct ddebug_class_map *map = iter->table->classes; > + int i, nc = iter->table->num_classes; > > - list_for_each_entry(map, &iter->table->maps, link) > + for (i = 0; i < nc; i++, map++) > if (class_in_range(dp->class_id, map)) > return map->class_names[dp->class_id - map->base]; > > @@ -1208,30 +1211,31 @@ static const struct proc_ops proc_fops = { > .proc_write = ddebug_proc_write > }; > > -static void ddebug_attach_module_classes(struct ddebug_table *dt, > - struct ddebug_class_map *classes, > - int num_classes) > +static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di) > { > struct ddebug_class_map *cm; > - int i, j, ct = 0; > + int i, nc = 0; > > - for (cm = classes, i = 0; i < num_classes; i++, cm++) { > + /* > + * Find this module's classmaps in a subrange/wholerange of > + * the builtin/modular classmap vector/section. Save the start > + * and length of the subrange at its edges. > + */ > + for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) { > > if (!strcmp(cm->mod_name, dt->mod_name)) { > - > - v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i, > - cm->mod_name, cm->base, cm->length, cm->map_type); > - > - for (j = 0; j < cm->length; j++) > - v3pr_info(" %d: %d %s\n", j + cm->base, j, > - cm->class_names[j]); > - > - list_add(&cm->link, &dt->maps); > - ct++; > + if (!nc) { > + v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n", > + i, cm->mod_name, cm->base, cm->length, cm->map_type); > + dt->classes = cm; > + } > + nc++; > } > } > - if (ct) > - vpr_info("module:%s attached %d classes\n", dt->mod_name, ct); > + if (nc) { > + dt->num_classes = nc; > + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc); > + } > } > > /* > @@ -1263,10 +1267,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname) > dt->num_ddebugs = di->num_descs; > > INIT_LIST_HEAD(&dt->link); > - INIT_LIST_HEAD(&dt->maps); > > if (di->classes && di->num_classes) > - ddebug_attach_module_classes(dt, di->classes, di->num_classes); > + ddebug_attach_module_classes(dt, di); > > mutex_lock(&ddebug_lock); > list_add_tail(&dt->link, &ddebug_tables); > @@ -1379,8 +1382,8 @@ static void ddebug_remove_all_tables(void) > mutex_lock(&ddebug_lock); > while (!list_empty(&ddebug_tables)) { > struct ddebug_table *dt = list_entry(ddebug_tables.next, > - struct ddebug_table, > - link); > + struct ddebug_table, > + link); > ddebug_table_free(dt); > } > mutex_unlock(&ddebug_lock); -- Louis Chauvet, Bootlin Embedded Linux and Kernel engineering https://bootlin.com