From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751029AbWD3HU3 (ORCPT ); Sun, 30 Apr 2006 03:20:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751031AbWD3HU2 (ORCPT ); Sun, 30 Apr 2006 03:20:28 -0400 Received: from fmr17.intel.com ([134.134.136.16]:27600 "EHLO orsfmr002.jf.intel.com") by vger.kernel.org with ESMTP id S1751027AbWD3HU2 (ORCPT ); Sun, 30 Apr 2006 03:20:28 -0400 Subject: Re: [PATCH] don't use flush_tlb_all in suspend time From: Shaohua Li To: Andrew Morton Cc: pavel@ucw.cz, linux-kernel@vger.kernel.org In-Reply-To: <20060429235721.1d081ea5.akpm@osdl.org> References: <1146367462.21486.10.camel@sli10-desk.sh.intel.com> <20060430064505.GA5091@ucw.cz> <1146379596.8456.4.camel@sli10-desk.sh.intel.com> <20060429235721.1d081ea5.akpm@osdl.org> Content-Type: text/plain Date: Sun, 30 Apr 2006 15:19:04 +0800 Message-Id: <1146381544.8456.6.camel@sli10-desk.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2006-04-29 at 23:57 -0700, Andrew Morton wrote: > Shaohua Li wrote: > > > > On Sun, 2006-04-30 at 06:45 +0000, Pavel Machek wrote: > > > Hi! > > > > > > > flush_tlb_all uses on_each_cpu, which will disable/enable interrupt. > > > > In suspend/resume time, this will make interrupt wrongly enabled. > > > > > > > diff -puN arch/i386/mm/init.c~flush_tlb_all_check arch/i386/mm/init.c > > > > --- linux-2.6.17-rc3/arch/i386/mm/init.c~flush_tlb_all_check 2006-04-29 08:47:05.000000000 +0800 > > > > +++ linux-2.6.17-rc3-root/arch/i386/mm/init.c 2006-04-29 08:48:15.000000000 +0800 > > > > @@ -420,7 +420,10 @@ void zap_low_mappings (void) > > > > #else > > > > set_pgd(swapper_pg_dir+i, __pgd(0)); > > > > #endif > > > > - flush_tlb_all(); > > > > + if (cpus_weight(cpu_online_map) == 1) > > > > + local_flush_tlb(); > > > > + else > > > > + flush_tlb_all(); > > > > } > > > > > > > > > > Either it is okay to enable interrupts here -> unneccessary and ugly > > > test, or it is not, and then we are broken in SMP case. > > It's not broken in SMP case, APs are offlined here in suspend/resume. > > > > In which case, how's about this? Yes, this is great. Thanks! > arch/i386/kernel/acpi/sleep.c | 3 +++ > arch/i386/mm/init.c | 10 +++++++++- > arch/x86_64/kernel/acpi/sleep.c | 3 +++ > 3 files changed, 15 insertions(+), 1 deletion(-) > > diff -puN arch/i386/kernel/acpi/sleep.c~dont-use-flush_tlb_all-in-suspend-time-tidy arch/i386/kernel/acpi/sleep.c > --- devel/arch/i386/kernel/acpi/sleep.c~dont-use-flush_tlb_all-in-suspend-time-tidy 2006-04-29 23:53:33.000000000 -0700 > +++ devel-akpm/arch/i386/kernel/acpi/sleep.c 2006-04-29 23:54:09.000000000 -0700 > @@ -8,6 +8,8 @@ > #include > #include > #include > +#include > + > #include > #include > > @@ -29,6 +31,7 @@ static void init_low_mapping(pgd_t * pgd > set_pgd(pgd, *(pgd + USER_PTRS_PER_PGD)); > pgd_ofs++, pgd++; > } > + WARN_ON(num_online_cpus() != 1); > local_flush_tlb(); > } > > diff -puN arch/i386/mm/init.c~dont-use-flush_tlb_all-in-suspend-time-tidy arch/i386/mm/init.c > --- devel/arch/i386/mm/init.c~dont-use-flush_tlb_all-in-suspend-time-tidy 2006-04-29 23:53:33.000000000 -0700 > +++ devel-akpm/arch/i386/mm/init.c 2006-04-29 23:56:00.000000000 -0700 > @@ -29,6 +29,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -420,7 +421,14 @@ void zap_low_mappings (void) > #else > set_pgd(swapper_pg_dir+i, __pgd(0)); > #endif > - if (cpus_weight(cpu_online_map) == 1) > + /* > + * We can be called at suspend/resume time, with local interrupts > + * disabled. But flush_tlb_all() requires that local interrupts be > + * enabled. > + * > + * Happily, the APs are not yet started, so we can use local_flush_tlb() * in that case > + */ > + if (num_online_cpus() == 1) > local_flush_tlb(); > else > flush_tlb_all(); > diff -puN arch/x86_64/kernel/acpi/sleep.c~dont-use-flush_tlb_all-in-suspend-time-tidy arch/x86_64/kernel/acpi/sleep.c > --- devel/arch/x86_64/kernel/acpi/sleep.c~dont-use-flush_tlb_all-in-suspend-time-tidy 2006-04-29 23:53:33.000000000 -0700 > +++ devel-akpm/arch/x86_64/kernel/acpi/sleep.c 2006-04-29 23:56:24.000000000 -0700 > @@ -35,6 +35,8 @@ > #include > #include > #include > +#include > + > #include > #include > #include > @@ -66,6 +68,7 @@ static void init_low_mapping(void) > pgd_t *slot0 = pgd_offset(current->mm, 0UL); > low_ptr = *slot0; > set_pgd(slot0, *pgd_offset(current->mm, PAGE_OFFSET)); > + WARN_ON(num_online_cpus() != 1); > local_flush_tlb(); > } > > _ -- Shaohua Li