From: Souptick Joarder <jrdr.linux@gmail.com> To: Dan Carpenter <dan.carpenter@oracle.com>, John Hubbard <jhubbard@nvidia.com> Cc: Rob Springer <rspringer@google.com>, Todd Poynor <toddpoynor@google.com>, benchan@chromium.org, Greg KH <gregkh@linuxfoundation.org>, "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging: gasket: Convert get_user_pages*() --> pin_user_pages*() Date: Fri, 29 May 2020 11:57:09 +0530 [thread overview] Message-ID: <CAFqt6zbtg0NWbAnDGPC0ZddEiTeohz=8JN+S_KxqM0bnnvar3g@mail.gmail.com> (raw) In-Reply-To: <CAFqt6zaKWBQTy9XfvxwVAvzGS+gz9Qv1gL8Bv1VxLq+THYf+Aw@mail.gmail.com> On Fri, May 29, 2020 at 11:46 AM Souptick Joarder <jrdr.linux@gmail.com> wrote: > > On Thu, May 28, 2020 at 4:34 PM Dan Carpenter <dan.carpenter@oracle.com> wrote: > > > > On Thu, May 28, 2020 at 02:32:42AM +0530, Souptick Joarder wrote: > > > This code was using get_user_pages_fast(), in a "Case 2" scenario > > > (DMA/RDMA), using the categorization from [1]. That means that it's > > > time to convert the get_user_pages_fast() + put_page() calls to > > > pin_user_pages_fast() + unpin_user_page() calls. > > > > You are saying that the page is used for DIO and not DMA, but it sure > > looks to me like it is used for DMA. > > No, I was referring to "Case 2" scenario in change log which means it is > used for DMA, not DIO. > > > > > 503 /* Map the page into DMA space. */ > > 504 ptes[i].dma_addr = > > 505 dma_map_page(pg_tbl->device, page, 0, PAGE_SIZE, > > 506 DMA_BIDIRECTIONAL); > > > > To be honest, that starting paragraph was confusing. At first I thought > > you were saying gasket was an RDMA driver. :P I shouldn't have to read > > a different document to understand the commit message. It should be > > summarized enough and the other documentation is supplemental. > > > > "In 2019 we introduced pin_user_pages() and now we are converting > > get_user_pages() to the new API as appropriate". > > As all other similar conversion have similar change logs, so I was trying > to maintain the same. John might have a different opinion on this. For example, I was referring to few recent similar commits for change logs. http://lkml.kernel.org/r/20200519002124.2025955-5-jhubbard@nvidia.com https://lore.kernel.org/r/20200518015237.1568940-1-jhubbard@nvidia.com > > John, Any further opinion ?? > > > > > > > > > There is some helpful background in [2]: basically, this is a small > > > part of fixing a long-standing disconnect between pinning pages, and > > > file systems' use of those pages. > > > > What is the impact of this patch on runtime? > > I don't have the hardware to validate the runtime impact and will > wait if someone is going to validate it for runtime impact. > > > > > > > > > [1] Documentation/core-api/pin_user_pages.rst > > > > > > [2] "Explicit pinning of user-space pages": > > > https://lwn.net/Articles/807108/ > > > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > > Cc: John Hubbard <jhubbard@nvidia.com> > > > > > > Hi, > > > > > > I'm compile tested this, but unable to run-time test, so any testing > > > help is much appriciated. > > > --- > > > > The "Hi" part of patch should have been under the "---" cut off line so > > this will definitely need to be resent. > > Sorry about it. > Will wait for feedback from John before resend it :) > > > > > regards, > > dan carpenter > >
WARNING: multiple messages have this Message-ID (diff)
From: Souptick Joarder <jrdr.linux@gmail.com> To: Dan Carpenter <dan.carpenter@oracle.com>, John Hubbard <jhubbard@nvidia.com> Cc: "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>, Greg KH <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org, Rob Springer <rspringer@google.com>, Todd Poynor <toddpoynor@google.com> Subject: Re: [PATCH] staging: gasket: Convert get_user_pages*() --> pin_user_pages*() Date: Fri, 29 May 2020 11:57:09 +0530 [thread overview] Message-ID: <CAFqt6zbtg0NWbAnDGPC0ZddEiTeohz=8JN+S_KxqM0bnnvar3g@mail.gmail.com> (raw) In-Reply-To: <CAFqt6zaKWBQTy9XfvxwVAvzGS+gz9Qv1gL8Bv1VxLq+THYf+Aw@mail.gmail.com> On Fri, May 29, 2020 at 11:46 AM Souptick Joarder <jrdr.linux@gmail.com> wrote: > > On Thu, May 28, 2020 at 4:34 PM Dan Carpenter <dan.carpenter@oracle.com> wrote: > > > > On Thu, May 28, 2020 at 02:32:42AM +0530, Souptick Joarder wrote: > > > This code was using get_user_pages_fast(), in a "Case 2" scenario > > > (DMA/RDMA), using the categorization from [1]. That means that it's > > > time to convert the get_user_pages_fast() + put_page() calls to > > > pin_user_pages_fast() + unpin_user_page() calls. > > > > You are saying that the page is used for DIO and not DMA, but it sure > > looks to me like it is used for DMA. > > No, I was referring to "Case 2" scenario in change log which means it is > used for DMA, not DIO. > > > > > 503 /* Map the page into DMA space. */ > > 504 ptes[i].dma_addr = > > 505 dma_map_page(pg_tbl->device, page, 0, PAGE_SIZE, > > 506 DMA_BIDIRECTIONAL); > > > > To be honest, that starting paragraph was confusing. At first I thought > > you were saying gasket was an RDMA driver. :P I shouldn't have to read > > a different document to understand the commit message. It should be > > summarized enough and the other documentation is supplemental. > > > > "In 2019 we introduced pin_user_pages() and now we are converting > > get_user_pages() to the new API as appropriate". > > As all other similar conversion have similar change logs, so I was trying > to maintain the same. John might have a different opinion on this. For example, I was referring to few recent similar commits for change logs. http://lkml.kernel.org/r/20200519002124.2025955-5-jhubbard@nvidia.com https://lore.kernel.org/r/20200518015237.1568940-1-jhubbard@nvidia.com > > John, Any further opinion ?? > > > > > > > > > There is some helpful background in [2]: basically, this is a small > > > part of fixing a long-standing disconnect between pinning pages, and > > > file systems' use of those pages. > > > > What is the impact of this patch on runtime? > > I don't have the hardware to validate the runtime impact and will > wait if someone is going to validate it for runtime impact. > > > > > > > > > [1] Documentation/core-api/pin_user_pages.rst > > > > > > [2] "Explicit pinning of user-space pages": > > > https://lwn.net/Articles/807108/ > > > > > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > > > Cc: John Hubbard <jhubbard@nvidia.com> > > > > > > Hi, > > > > > > I'm compile tested this, but unable to run-time test, so any testing > > > help is much appriciated. > > > --- > > > > The "Hi" part of patch should have been under the "---" cut off line so > > this will definitely need to be resent. > > Sorry about it. > Will wait for feedback from John before resend it :) > > > > > regards, > > dan carpenter > > _______________________________________________ devel mailing list devel@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
next prev parent reply other threads:[~2020-05-29 6:27 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-27 21:02 [PATCH] staging: gasket: Convert get_user_pages*() --> pin_user_pages*() Souptick Joarder 2020-05-27 21:02 ` Souptick Joarder 2020-05-28 11:04 ` Dan Carpenter 2020-05-28 11:04 ` Dan Carpenter 2020-05-29 6:16 ` Souptick Joarder 2020-05-29 6:16 ` Souptick Joarder 2020-05-29 6:27 ` Souptick Joarder [this message] 2020-05-29 6:27 ` Souptick Joarder 2020-05-29 7:38 ` John Hubbard 2020-05-29 7:38 ` John Hubbard 2020-05-29 7:45 ` Dan Carpenter 2020-05-29 7:45 ` Dan Carpenter 2020-05-29 7:46 ` Dan Carpenter 2020-05-29 7:46 ` Dan Carpenter 2020-05-29 8:00 ` John Hubbard 2020-05-29 8:00 ` John Hubbard 2020-05-29 11:53 ` Dan Carpenter 2020-05-29 11:53 ` Dan Carpenter 2020-05-29 20:28 ` John Hubbard 2020-05-29 20:28 ` John Hubbard 2020-05-31 7:23 Souptick Joarder 2020-05-31 7:23 ` Souptick Joarder 2020-05-31 8:59 ` Dan Carpenter 2020-05-31 8:59 ` Dan Carpenter
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