From: Arnd Bergmann <arnd@arndb.de> To: Sven Peter <sven@svenpeter.dev> Cc: Arnd Bergmann <arnd@arndb.de>, Keith Busch <kbusch@kernel.org>, "axboe@fb.com" <axboe@fb.com>, "hch@lst.de" <hch@lst.de>, "sagi@grimberg.me" <sagi@grimberg.me>, Hector Martin <marcan@marcan.st>, Alyssa Rosenzweig <alyssa@rosenzweig.io>, Rob Herring <robh+dt@kernel.org>, Marc Zyngier <maz@kernel.org>, DTML <devicetree@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-nvme@lists.infradead.org Subject: Re: [PATCH 6/9] nvme-apple: Add initial Apple SoC NVMe driver Date: Sat, 2 Apr 2022 23:26:28 +0200 [thread overview] Message-ID: <CAK8P3a3d5XmtXxGwVHFSyNraOJdTaFCG1s+LNev=39eLXxGFHg@mail.gmail.com> (raw) In-Reply-To: <7876eb84-9803-48dc-ab6b-27d49858e27a@www.fastmail.com> On Sat, Apr 2, 2022 at 3:34 PM Sven Peter <sven@svenpeter.dev> wrote: > On Tue, Mar 22, 2022, at 14:38, Arnd Bergmann wrote: > > On Mon, Mar 21, 2022 at 5:50 PM Sven Peter <sven@svenpeter.dev> wrote: > >> +bad_sgl: > >> + WARN(DO_ONCE(apple_nvme_print_sgl, iod->sg, iod->nents), > >> + "Invalid SGL for payload:%d nents:%d\n", blk_rq_payload_bytes(req), > >> + iod->nents); > > > > I think you mean WARN_ONCE() here? > > This is taken from pci.c which used to use WARN_ONCE but was replaced in > d08774738446e77734777adcf5d1045237b4475a with this construction here. > The commit message mentions > > The WARN_ONCE macro returns true if the condition is true, not if the > warn was raised, so we're printing the scatter list every time it's > invalid. This is excessive and makes debugging harder, so this patch > prints it just once. > Ok, makes sense. If we get more of these in the kernel, we may want to add a helper that makes this more obvious, but it appears that for now these two are the only ones. It could also be expressed by moving the WARN_ONCE() into the condition above the 'goto', but I don't see a reason to change the other driver and it's better to keep the two consistent. > Agreed, I've actually tried replacing all non-relaxed ones with the normal > accessors (even those inside the hot path) and didn't see any performance > difference. > I can use the normal ones here and I'll consider using the non-relaxed ones > in the hot path together with a comment why they are safe in those places. Sounds good. If you find any instances in the hot path that have a corresponding version in the pci.c file, it would be good to keep these two in sync, hopefully making the non-apple case faster as well. Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de> To: Sven Peter <sven@svenpeter.dev> Cc: Arnd Bergmann <arnd@arndb.de>, Keith Busch <kbusch@kernel.org>, "axboe@fb.com" <axboe@fb.com>, "hch@lst.de" <hch@lst.de>, "sagi@grimberg.me" <sagi@grimberg.me>, Hector Martin <marcan@marcan.st>, Alyssa Rosenzweig <alyssa@rosenzweig.io>, Rob Herring <robh+dt@kernel.org>, Marc Zyngier <maz@kernel.org>, DTML <devicetree@vger.kernel.org>, Linux ARM <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, linux-nvme@lists.infradead.org Subject: Re: [PATCH 6/9] nvme-apple: Add initial Apple SoC NVMe driver Date: Sat, 2 Apr 2022 23:26:28 +0200 [thread overview] Message-ID: <CAK8P3a3d5XmtXxGwVHFSyNraOJdTaFCG1s+LNev=39eLXxGFHg@mail.gmail.com> (raw) In-Reply-To: <7876eb84-9803-48dc-ab6b-27d49858e27a@www.fastmail.com> On Sat, Apr 2, 2022 at 3:34 PM Sven Peter <sven@svenpeter.dev> wrote: > On Tue, Mar 22, 2022, at 14:38, Arnd Bergmann wrote: > > On Mon, Mar 21, 2022 at 5:50 PM Sven Peter <sven@svenpeter.dev> wrote: > >> +bad_sgl: > >> + WARN(DO_ONCE(apple_nvme_print_sgl, iod->sg, iod->nents), > >> + "Invalid SGL for payload:%d nents:%d\n", blk_rq_payload_bytes(req), > >> + iod->nents); > > > > I think you mean WARN_ONCE() here? > > This is taken from pci.c which used to use WARN_ONCE but was replaced in > d08774738446e77734777adcf5d1045237b4475a with this construction here. > The commit message mentions > > The WARN_ONCE macro returns true if the condition is true, not if the > warn was raised, so we're printing the scatter list every time it's > invalid. This is excessive and makes debugging harder, so this patch > prints it just once. > Ok, makes sense. If we get more of these in the kernel, we may want to add a helper that makes this more obvious, but it appears that for now these two are the only ones. It could also be expressed by moving the WARN_ONCE() into the condition above the 'goto', but I don't see a reason to change the other driver and it's better to keep the two consistent. > Agreed, I've actually tried replacing all non-relaxed ones with the normal > accessors (even those inside the hot path) and didn't see any performance > difference. > I can use the normal ones here and I'll consider using the non-relaxed ones > in the hot path together with a comment why they are safe in those places. Sounds good. If you find any instances in the hot path that have a corresponding version in the pci.c file, it would be good to keep these two in sync, hopefully making the non-apple case faster as well. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-04-02 21:26 UTC|newest] Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-03-21 16:50 [PATCH 0/9] Apple M1 (Pro/Max) NVMe driver Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` [PATCH 1/9] dt-bindings: soc: apple: Add Apple SART Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-31 21:23 ` Rob Herring 2022-03-31 21:23 ` Rob Herring 2022-04-02 12:58 ` Sven Peter 2022-04-02 12:58 ` Sven Peter 2022-03-21 16:50 ` [PATCH 2/9] dt-bindings: soc: apple: Add ANS NVMe Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-23 11:14 ` Krzysztof Kozlowski 2022-03-23 11:14 ` Krzysztof Kozlowski 2022-04-02 13:05 ` Sven Peter 2022-04-02 13:05 ` Sven Peter 2022-04-02 16:06 ` Krzysztof Kozlowski 2022-04-02 16:06 ` Krzysztof Kozlowski 2022-03-21 16:50 ` [PATCH 3/9] soc: apple: Always include Makefile Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` [PATCH 4/9] soc: apple: Add SART driver Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 17:07 ` Arnd Bergmann 2022-03-21 17:07 ` Arnd Bergmann 2022-04-02 12:38 ` Sven Peter 2022-04-02 12:38 ` Sven Peter 2022-04-02 19:07 ` Arnd Bergmann 2022-04-02 19:07 ` Arnd Bergmann 2022-04-04 14:58 ` Rob Herring 2022-04-04 14:58 ` Rob Herring 2022-04-04 15:01 ` Hector Martin 2022-04-04 15:01 ` Hector Martin 2022-04-05 15:37 ` Sven Peter 2022-04-05 15:37 ` Sven Peter 2022-03-21 17:17 ` Alyssa Rosenzweig 2022-03-21 17:17 ` Alyssa Rosenzweig 2022-04-02 12:40 ` Sven Peter 2022-04-02 12:40 ` Sven Peter 2022-03-21 16:50 ` [PATCH 5/9] soc: apple: Add RTKit IPC library Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-22 13:13 ` Arnd Bergmann 2022-03-22 13:13 ` Arnd Bergmann 2022-03-22 17:41 ` Robin Murphy 2022-03-22 17:41 ` Robin Murphy 2022-04-02 12:56 ` Sven Peter 2022-04-02 12:56 ` Sven Peter 2022-04-02 18:30 ` Arnd Bergmann 2022-04-02 18:30 ` Arnd Bergmann 2022-04-03 10:45 ` Sven Peter 2022-04-03 10:45 ` Sven Peter 2022-03-22 17:23 ` Alyssa Rosenzweig 2022-03-22 17:23 ` Alyssa Rosenzweig 2022-04-02 12:50 ` Sven Peter 2022-04-02 12:50 ` Sven Peter 2022-03-23 11:19 ` Krzysztof Kozlowski 2022-03-23 11:19 ` Krzysztof Kozlowski 2022-04-02 13:51 ` Sven Peter 2022-04-02 13:51 ` Sven Peter 2022-04-02 16:08 ` Krzysztof Kozlowski 2022-04-02 16:08 ` Krzysztof Kozlowski 2022-04-04 15:02 ` Rob Herring 2022-04-04 15:02 ` Rob Herring 2022-04-04 15:47 ` Hector Martin 2022-04-04 15:47 ` Hector Martin 2022-03-21 16:50 ` [PATCH 6/9] nvme-apple: Add initial Apple SoC NVMe driver Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 17:01 ` Keith Busch 2022-03-21 17:01 ` Keith Busch 2022-04-02 13:10 ` Sven Peter 2022-04-02 13:10 ` Sven Peter 2022-03-22 13:38 ` Arnd Bergmann 2022-03-22 13:38 ` Arnd Bergmann 2022-04-02 13:34 ` Sven Peter 2022-04-02 13:34 ` Sven Peter 2022-04-02 13:58 ` Janne Grunau 2022-04-02 13:58 ` Janne Grunau 2022-04-02 14:02 ` Sven Peter 2022-04-02 14:02 ` Sven Peter 2022-04-02 21:26 ` Arnd Bergmann [this message] 2022-04-02 21:26 ` Arnd Bergmann 2022-03-24 6:16 ` Christoph Hellwig 2022-03-24 6:16 ` Christoph Hellwig 2022-04-02 12:47 ` Sven Peter 2022-04-02 12:47 ` Sven Peter 2022-04-04 15:57 ` Hector Martin 2022-04-04 15:57 ` Hector Martin 2022-04-04 15:59 ` Christoph Hellwig 2022-04-04 15:59 ` Christoph Hellwig 2022-04-04 16:03 ` Sven Peter 2022-04-04 16:03 ` Sven Peter 2022-04-04 16:05 ` hch 2022-04-04 16:05 ` hch 2022-04-04 16:05 ` Hector Martin 2022-04-04 16:05 ` Hector Martin 2022-04-04 18:29 ` Jens Axboe 2022-04-04 18:29 ` Jens Axboe 2022-04-05 6:24 ` Christoph Hellwig 2022-04-05 6:24 ` Christoph Hellwig 2022-03-21 16:50 ` [PATCH 7/9] nvme-apple: Serialize command issue Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-24 6:16 ` Christoph Hellwig 2022-03-24 6:16 ` Christoph Hellwig 2022-04-02 12:42 ` Sven Peter 2022-04-02 12:42 ` Sven Peter 2022-03-21 16:50 ` [PATCH 8/9] nvme-apple: Add support for multiple power domains Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-21 16:50 ` [PATCH 9/9] nvme-apple: Add support for suspend/resume Sven Peter 2022-03-21 16:50 ` Sven Peter 2022-03-24 6:17 ` Christoph Hellwig 2022-03-24 6:17 ` Christoph Hellwig 2022-03-22 17:26 ` [PATCH 0/9] Apple M1 (Pro/Max) NVMe driver Alyssa Rosenzweig 2022-03-22 17:26 ` Alyssa Rosenzweig
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