From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpng3.m.smailru.net (smtpng3.m.smailru.net [94.100.177.149]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id C427546970E for ; Sat, 1 Feb 2020 01:30:10 +0300 (MSK) Date: Sat, 1 Feb 2020 01:30:14 +0300 From: Sergey Kaplun Message-ID: <20200131223014.GA18554@root> References: <20200123084445.7452-1-skaplun@tarantool.org> <290fd1a1-022d-d0cf-d823-df6008872029@tarantool.org> <20200129133609.GD547@tarantool.org> <82333230-a66a-0ae0-f57b-f9ab930b4608@tarantool.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <82333230-a66a-0ae0-f57b-f9ab930b4608@tarantool.org> Subject: Re: [Tarantool-patches] [PATCH v2] refactoring: drop excess 16Kb bss buffer List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Leonid Vasiliev , tarantool-patches@dev.tarantool.org Cc: Vladislav Shpilevoy Hi! Thanks for your feedback! On 30.01.20, Leonid Vasiliev wrote: > > Hi. > > On 1/29/20 4:36 PM, Sergey Ostanevich wrote: > > Hi! > > > > Thanks for the patch! > > > > LGTM after updates below. > > > > Regards, > > Sergos > > > > > > On 23 Jan 23:04, Vladislav Shpilevoy wrote: > >> Hi! Thanks for the patch! > >> > >> I agree with everything what Leonid said. > > > > I will object both assertion and NULL handling. Just have a look: > > > >>> + char *backtrace_buf = (char *)static_alloc(SMALL_STATIC_SIZE); > > > > And in static_reserve(size_t size) called from static_alloc(): > > > > if (size > SMALL_STATIC_SIZE) > > return NULL; > > > > is the only place NULL can be returned. No need to test if > > SMALL_STATIC_SIZE > SMALL_STATIC_SIZE, just ask me :) > > Hmm, it's sounds like:"Client must known about implementation of library > function". But implementation can be changed with the contract save. > To be honest, I do not see any dependencies on internal API in this, since the module determines SMALL_STATIC_SIZE and provides extern __thread char static_storage_buffer[SMALL_STATIC_SIZE]; - all of this is part of API, isn't it? Proposal: we can use sizeof(static_storage_buffer) to avoid usage of "magic" SMALL_STATIC_SIZE. > > > > > > > >> > >> On 23/01/2020 09:44, Sergey Kaplun wrote: > >>> We already have 12Kb thread-safe static buffer > >>> in `lib/small/small/static.h`, that can be used instead of 16Kb > >>> bss buffer in `src/lib/core/backtrace.cc` for backtrace payload. > >>> Closes #4650 > >>> --- > >>> > >>> branch: https://github.com/tarantool/tarantool/tree/skaplun/drop-bss-buff > >>> issue: https://github.com/tarantool/tarantool/issues/4650 > >>> > >>> src/lib/core/backtrace.cc | 8 +++++--- > >>> 1 file changed, 5 insertions(+), 3 deletions(-) > >>> > >>> diff --git a/src/lib/core/backtrace.cc b/src/lib/core/backtrace.cc > >>> index 77f77b05c..c70576b53 100644 > >>> --- a/src/lib/core/backtrace.cc > >>> +++ b/src/lib/core/backtrace.cc > >>> @@ -33,6 +33,7 @@ > >>> > >>> #include > >>> #include > >>> +#include > >>> > >>> #include > >>> > >>> @@ -47,6 +48,7 @@ > >>> #include > >>> > >>> #include "small/region.h" > >>> +#include "small/static.h" > >>> /* > >>> * We use a global static buffer because it is too late to do any > >>> * allocation when we are printing backtrace and fiber stack is > > > > Just change "global static buffer" for the "static buffer interface". > > > >>> @@ -55,8 +57,6 @@ > >>> > >>> #define BACKTRACE_NAME_MAX 200 > >>> > >>> -static char backtrace_buf[4096 * 4]; > >>> - > >>> static __thread struct region cache_region; > >>> static __thread struct mh_i64ptr_t *proc_cache = NULL; > >>> > >>> @@ -140,8 +140,10 @@ backtrace() > >>> unw_getcontext(&unw_context); > >>> unw_cursor_t unw_cur; > >>> unw_init_local(&unw_cur, &unw_context); > >>> + char *backtrace_buf = (char *)static_alloc(SMALL_STATIC_SIZE); > >>> + assert(backtrace_buf); > >>> char *p = backtrace_buf; > >>> - char *end = p + sizeof(backtrace_buf) - 1; > >>> + char *end = p + SMALL_STATIC_SIZE - 1; > >>> int unw_status; > >>> *p = '\0'; > >>> while ((unw_status = unw_step(&unw_cur)) > 0) { > >>>