From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
Dan Williams <dan.j.williams@intel.com>,
Erik Kaneda <erik.kaneda@intel.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Len Brown <lenb@kernel.org>, Borislav Petkov <bp@alien8.de>,
Ira Weiny <ira.weiny@intel.com>,
James Morse <james.morse@arm.com>,
Myron Stowe <myron.stowe@redhat.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
Bob Moore <robert.moore@intel.com>
Subject: Re: [RFT][PATCH v2 2/4] ACPI: OSL: Add support for deferred unmapping of ACPI memory
Date: Mon, 22 Jun 2020 17:27:53 +0200 [thread overview]
Message-ID: <CAJZ5v0hu9_TA0KAe=9ZCSG4_KijSYb=qnt8MYe9QYwGbz=pmBg@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VePDyPevCAOntFpTajf5zd9ocwjeWRz80WmCNtiDicpLg@mail.gmail.com>
On Mon, Jun 22, 2020 at 4:56 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, Jun 22, 2020 at 5:06 PM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> >
> > From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
> >
> > Implement acpi_os_unmap_deferred() and
> > acpi_os_release_unused_mappings() and set ACPI_USE_DEFERRED_UNMAPPING
> > to allow ACPICA to use deferred unmapping of memory in
> > acpi_ex_system_memory_space_handler() so as to avoid RCU-related
> > performance issues with memory opregions.
>
> ...
>
> > +static bool acpi_os_drop_map_ref(struct acpi_ioremap *map, bool defer)
> > {
> > - unsigned long refcount = --map->refcount;
> > + if (--map->track.refcount)
> > + return true;
> >
> > - if (!refcount)
> > - list_del_rcu(&map->list);
> > - return refcount;
> > + list_del_rcu(&map->list);
> > +
>
> > + if (defer) {
> > + INIT_LIST_HEAD(&map->track.gc);
> > + list_add_tail(&map->track.gc, &unused_mappings);
>
> > + return true;
> > + }
> > +
> > + return false;
>
> A nit:
>
> Effectively it returns a value of defer.
>
> return defer;
>
> > }
Do you mean that one line of code could be saved? Yes, it could.
>
> ...
>
> > @@ -416,26 +421,102 @@ void __ref acpi_os_unmap_iomem(void __iomem *virt, acpi_size size)
> > }
> >
> > mutex_lock(&acpi_ioremap_lock);
> > +
> > map = acpi_map_lookup_virt(virt, size);
>
> A nit: should it be somewhere else (I mean in another patch)?
Do you mean the extra empty line?
No, I don't think so, or the code style after this patch would not
look consistent.
> > if (!map) {
>
> ...
>
> > + /* Release the unused mappings in the list. */
> > + while (!list_empty(&list)) {
> > + struct acpi_ioremap *map;
> > +
> > + map = list_entry(list.next, struct acpi_ioremap, track.gc);
>
> A nt: if __acpi_os_map_cleanup() (actually acpi_unmap() according to
> the code) has no side effects, can we use list_for_each_entry_safe()
> here?
I actually prefer a do .. while version of this which saves the
initial check (which has been carried out already).
> > + list_del(&map->track.gc);
> > + __acpi_os_map_cleanup(map);
> > + }
> > +}
>
> ...
>
> > @@ -472,16 +552,18 @@ void acpi_os_unmap_generic_address(struct acpi_generic_address *gas)
> > return;
> >
> > mutex_lock(&acpi_ioremap_lock);
> > +
> > map = acpi_map_lookup(addr, gas->bit_width / 8);
>
> A nit: should it be somewhere else (I mean in another patch)?
Nope.
Thanks!
next prev parent reply other threads:[~2020-06-22 15:28 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 23:39 [PATCH v2] ACPI: Drop rcu usage for MMIO mappings Dan Williams
2020-06-05 13:32 ` Rafael J. Wysocki
2020-06-05 16:18 ` Dan Williams
2020-06-05 16:21 ` Rafael J. Wysocki
2020-06-05 16:39 ` Dan Williams
2020-06-05 17:02 ` Rafael J. Wysocki
2020-06-05 14:06 ` [RFT][PATCH] ACPI: OSL: Use rwlock instead of RCU for memory management Rafael J. Wysocki
2020-06-05 17:08 ` Dan Williams
2020-06-06 6:56 ` Rafael J. Wysocki
2020-06-08 15:33 ` Rafael J. Wysocki
2020-06-08 16:29 ` Rafael J. Wysocki
2020-06-05 19:40 ` Andy Shevchenko
2020-06-06 6:48 ` Rafael J. Wysocki
2020-06-10 12:17 ` [RFT][PATCH 0/3] ACPI: ACPICA / OSL: Avoid unmapping ACPI memory inside of the AML interpreter Rafael J. Wysocki
2020-06-10 12:20 ` [RFT][PATCH 1/3] ACPICA: Defer unmapping of memory used in memory opregions Rafael J. Wysocki
2020-06-10 12:21 ` [RFT][PATCH 2/3] ACPICA: Remove unused memory mappings on interpreter exit Rafael J. Wysocki
2020-06-12 0:12 ` Kaneda, Erik
2020-06-12 12:05 ` Rafael J. Wysocki
2020-06-13 19:28 ` Rafael J. Wysocki
2020-06-15 19:06 ` Dan Williams
2020-06-10 12:22 ` [RFT][PATCH 3/3] ACPI: OSL: Define ACPI_OS_MAP_MEMORY_FAST_PATH() Rafael J. Wysocki
2020-06-13 19:19 ` [RFT][PATCH 0/3] ACPI: ACPICA / OSL: Avoid unmapping ACPI memory inside of the AML interpreter Rafael J. Wysocki
2020-06-22 13:50 ` [RFT][PATCH v2 0/4] " Rafael J. Wysocki
2020-06-22 13:52 ` [RFT][PATCH v2 1/4] ACPICA: Defer unmapping of opregion memory if supported by OS Rafael J. Wysocki
2020-06-22 13:53 ` [RFT][PATCH v2 2/4] ACPI: OSL: Add support for deferred unmapping of ACPI memory Rafael J. Wysocki
2020-06-22 14:56 ` Andy Shevchenko
2020-06-22 15:27 ` Rafael J. Wysocki [this message]
2020-06-22 15:46 ` Andy Shevchenko
2020-06-22 14:01 ` [RFT][PATCH v2 3/4] ACPICA: Preserve memory opregion mappings if supported by OS Rafael J. Wysocki
2020-06-26 22:53 ` Kaneda, Erik
2020-06-29 13:02 ` Rafael J. Wysocki
2020-06-22 14:02 ` [RFT][PATCH v2 4/4] ACPI: OSL: Implement acpi_os_map_memory_fast_path() Rafael J. Wysocki
2020-06-26 17:28 ` [RFT][PATCH v3 0/4] ACPI: ACPICA / OSL: Avoid unmapping ACPI memory inside of the AML interpreter Rafael J. Wysocki
2020-06-26 17:31 ` [RFT][PATCH v3 1/4] ACPICA: Take deferred unmapping of memory into account Rafael J. Wysocki
2020-06-26 17:31 ` [RFT][PATCH v3 2/4] ACPI: OSL: Implement deferred unmapping of ACPI memory Rafael J. Wysocki
2020-06-26 17:32 ` [RFT][PATCH v3 3/4] ACPICA: Preserve memory opregion mappings if supported by OS Rafael J. Wysocki
2020-06-26 17:33 ` [RFT][PATCH v3 4/4] ACPI: OSL: Implement acpi_os_map_memory_fast_path() Rafael J. Wysocki
2020-06-26 18:41 ` [RFT][PATCH v3 0/4] ACPI: ACPICA / OSL: Avoid unmapping ACPI memory inside of the AML interpreter Dan Williams
2020-06-28 17:09 ` Rafael J. Wysocki
2020-06-29 20:46 ` Dan Williams
2020-06-30 11:04 ` Rafael J. Wysocki
2020-06-29 16:31 ` [PATCH v4 0/2] " Rafael J. Wysocki
2020-06-29 16:33 ` [PATCH v4 1/2] ACPI: OSL: Implement deferred unmapping of ACPI memory Rafael J. Wysocki
2020-06-29 16:33 ` [PATCH v4 2/2] ACPICA: Preserve memory opregion mappings Rafael J. Wysocki
2020-06-29 20:57 ` Al Stone
2020-06-30 11:44 ` Rafael J. Wysocki
2020-06-30 15:31 ` Al Stone
2020-06-30 15:52 ` Rafael J. Wysocki
2020-06-30 19:57 ` Al Stone
2020-07-16 19:22 ` Verma, Vishal L
2020-07-19 19:14 ` Rafael J. Wysocki
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