From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 365D83849ACF for ; Fri, 19 Apr 2024 21:11:45 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 365D83849ACF Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 365D83849ACF Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1713561109; cv=none; b=k/O15tG7Km4mD0imMj9Vld8tVWCFthquKvhcmJocB4q1amAH5fZIA6r/tFU3a6KzE9Nj/FnM6GP1TTGj5avS94AqMcs4iruVt0vkNDNr4IHkG6nfHRYYQFwS+0h68LfE14wTf82Vi1NY3Cgtv2uX1w9mGgHhijcjhi4vYSCIy2I= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1713561109; c=relaxed/simple; bh=2EcefQ3zBXYo1yT3QIjQsnI5nfjcVXmOvtMd8AqJoJ8=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=wn0mw5tjfZfQR6VxDe2KDzN9JmPAxKduqD6uqZh6pX2MmV4n839EGQ1HHqSpH2SZCl9ysfRboerQhP4sx2MmfgmSCWhgdJllqLMzZt6jTALAtnvlr5o/wbc25Z8qdKZIcA3m9mY3JtKlwlDDeK9nbXsyC9Flz/uocmRY+zAK50U= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1713561104; 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: in-reply-to:in-reply-to; bh=E6ES0zzkQlwShCmciCK+wv34JiKg5Bhaw+ujFG0AelA=; b=LYb+i3H5HxT1Q9vfucCe/EYwevn77+gc6g3DcKPYmhsr7rwWOWN9Y4f3oy6AaTLd4oPpsf V/fnWcT8G6vvguqQ6Pk0AYcpGV37bVZzOlVURPIU0zYpYdLW1ihYTsl68CnSkQARFRcFl1 IL+3yqWao7RnWYn5AQRehlfDb5PLI4k= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-641-as-wr-gHPnqecDTKXrO9jg-1; Fri, 19 Apr 2024 17:11:41 -0400 X-MC-Unique: as-wr-gHPnqecDTKXrO9jg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 66BCD3806738; Fri, 19 Apr 2024 21:11:41 +0000 (UTC) Received: from greed.delorie.com (unknown [10.22.8.77]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5323BC1A225; Fri, 19 Apr 2024 21:11:41 +0000 (UTC) Received: from greed.delorie.com.redhat.com (localhost [127.0.0.1]) by greed.delorie.com (8.16.1/8.16.1) with ESMTP id 43JLBekQ2424754; Fri, 19 Apr 2024 17:11:40 -0400 From: DJ Delorie To: Szabolcs Nagy Cc: libc-alpha@sourceware.org Subject: Re: [PATCH v2 0/3] System-wide tunables In-Reply-To: (message from Szabolcs Nagy on Fri, 19 Apr 2024 09:41:43 +0100) Date: Fri, 19 Apr 2024 17:11:40 -0400 Message-ID: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-5.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Szabolcs Nagy writes: > tunables can differ across targets, so they need to be checked not to > cause trouble (e.g. doing a hwcap mask specified by an int instead of > arch feature can do different things across abis) This is no different than setting an environment variable today, right? The data stored in ld.so.cache has pre-computed IDs but also the string names, and the IDs are validated and recomputed in case libc.so changes. The value string is not parsed unless it's a generic "double" type, and even then, the string value is still included. I have not yet implemented any filters for the tunables, but it's already been requested to have an only/exclude filter for "per program image name". I suppose I could add a filter for only/exclude hwcaps too. Hmm... aren't tunables processed in ld.so, not libc.so If so, it's *already* more difficult to support multiple glibcs at the same time (tunables mismatch between ld.so and libc.so), unless you have a separate filesystem namespace, in which case you have a separate ld.so.cache also.