From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793825941; b=TT4ArWpG51dObUbEOXDNS+pl6KdsDvfMQP9IcXSXSvIndqwHQcxz/idvmuNJ7XKpyzFF Dlm8nwFx704mjrrU69R1+gL3+jOHtr59dUyOrXxRf+HlToJBiduvL0Xi6oo4ylpWqrhIL SN9SYqStcinbE5qee2X5rGbaPBpebrKCD4t+l94zb7y5FGSb3jCjwVk2H1igEV9s7AzPc 7X6gdtw3Hvv1bAYau3lfYsWsYJe9IvA3miAh/1CEs+Qu+bvN5/5SOciDqVRqgCMg/u3Fz ACBUhfJhXuFrvxQ1B/YpQn5wgTku/7CPB0FHpD2kXpuwdsBrP8+U7wBKl7jReaVTO6Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793825941; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=68FQQXsoJksoeoLSDrKS2zwovVFM1JhIN0EjI4tp+08=; b=wsSGaA3HOGuW3E+Pg1faqjz5Am72Bga/wMc5Db7kwJOgAyrkKYT8Z/kkViqGWhrNQD2Y bh2JrjvKkFJk5NCqLqE9H/xUH9PVRdEM6zsd57VOWuOOFdVv6Cv/bkPQ009U9x+ROPj5c 6TUBIexlMnuGBKuYlKNPDWvbf5rq3QIpneBQ99r1UEvrs8OOxyiaeh+0tnuHST4zbza5R /R2qkQjPae5qbffyrc0+B4pIeORvh30/Tq/NARPSep1+YRVpzpJTdxF8hGx3Bz4PtCKMq 8Dqbb3j8XqPFgGL+Hsf/HLNWx87265GzGHuosRMpgCG3rd1O02YDO4EiaiEYWeyT9pA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SRPUjx8Z; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C8AF606C599; Wed, 4 Nov 2026 20:59:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=SRPUjx8Z Received: by smtp.kernel.org (Postfix) with ESMTPSA id 643811F000C1; Wed, 4 Nov 2026 20:59:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793825940; bh=68FQQXsoJksoeoLSDrKS2zwovVFM1JhIN0EjI4tp+08=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SRPUjx8Zy48vSwkkaX/POKZ30Re+UiT7fzDFUOg6XDpSdch/779uWITaYR++cIW1t Yznj4/ZzvtLH3vrEYIF2RFx4aitSQxeYlD2lUaHQft6lRa0zEUiSROPPWGq6sMQ+i7 bzPT33Z5UOQHtpU9RegDhicrFq0frj/EaOP+pp0nr5iG0PyAgn0C52FmXdv/KYRI9J bNCpdCwj64zRjhZZh7qORt3ph1rsYndYtAWqE1QjKrRJ45qcLIBkds6gz67/irrjAZ pCdn+yEPv2rBJJHooDTVLQgbo9paAfeD553vL/zGB1k0IspviixUrWCR5BUBMJBmKg UMTKkG/wnmLmQ== Date: Wed, 4 Nov 2026 12:58:58 -0800 From: Namhyung Kim To: Stephen Brennan Cc: Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , James Clark , linux-perf-users@vger.kernel.org, Ian Rogers , Mark Rutland , linux-kernel@vger.kernel.org, Alexander Shishkin , Jiri Olsa , Adrian Hunter Subject: Re: [PATCH] tools: perf: allow opt-in "no-dso." files in /dev/shm Message-ID: References: <20261013213842.1870582-1-stephen.s.brennan@oracle.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20261013213842.1870582-1-stephen.s.brennan@oracle.com> On Tue, Oct 13, 2026 at 02:38:41PM -0700, Stephen Brennan wrote: > Applications can place JIT-compiled code in POSIX shared memory so that > multiple processes can execute the same code. On Linux, these shared > memory objects appear as file mappings under /dev/shm. > > Perf uses /tmp/perf-$pid.map to resolve symbols for executable SysV > shared memory mappings, but it treats /dev/shm mappings as ordinary > DSOs. As a result, applications which provide perf-map symbols for JIT > code in POSIX shared memory don't get those symbols resolved, while they > do with SysV shared memory. > > It would be incorrect to classify every /dev/shm mapping as no-DSO > memory though, because /dev/shm is just a tmpfs mount, and it can > contain ELF files. > > Add a filename prefix "/dev/shm/no-dso." which is recognized by > is_no_dso_memory(). Applications can opt-in by naming their shared > memory objects "no-dso.". Executable mappings with this prefix > will use the perf-map file, while other /dev/shm mappings will keep the > existing behavior. This allows applications that already emit perf maps > to use POSIX shared memory for JIT code, without needing to implement > jitdump support. > > Signed-off-by: Stephen Brennan Applied to perf-tools-next, thanks! Best regards Namhyung