pipe: add support for shrinking and growing pipes
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From: Jens Axboe on 24 May 2010 14:00 On Mon, May 24 2010, Michael Kerrisk wrote: > On Mon, May 24, 2010 at 7:35 PM, Jens Axboe <jens.axboe(a)oracle.com> wrote: > > On Mon, May 24 2010, Michael Kerrisk wrote: > >> > Right, that looks like a thinko. > >> > > >> > I'll submit a patch changing it to bytes and the agreed API and fix this > >> > -Eerror. Thanks for your comments and suggestions! > >> > >> Thanks. And of course you are welcome. (Please CC linux-api(a)vger on > >> this patche (and all patches that change the API/ABI.) > > > > The first change is this: > > > > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=0191f8697bbdfefcd36e7b8dc3eeddfe82893e4b > > > > and the one dealing with the pages vs bytes API is this: > > > > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=b9598db3401282bb27b4aef77e3eee12015f7f29 > > > > Not tested yet, will do so before sending in of course. > > Eyeballing it quickly, these changes look right. Good, thanks. > Do you have some test programs you can make available? Actually I don't, I test it by modifying fio's splice engine to set/get the pipe size and test the resulting transfers. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Michael Kerrisk on 24 May 2010 14:20 On Mon, May 24, 2010 at 8:12 PM, OGAWA Hirofumi <hirofumi(a)mail.parknet.co.jp> wrote: > Jens Axboe <jens.axboe(a)oracle.com> writes: > >>> > Isn't that pretty much what I described? >>> >>> Yes, probably. Well, 120kb was still multiple of page size. :) >> >> It is, but 120KB/page_size is not (which is the power-of-2 of interest >> here). > > Um... I have no interest whether rounded-up-size is power-of-2 or > not. Because it is implementation detail. > > Anyway, we agreed with "in bytes" and "at least"? If so, I'm happy with > it, and I'm sorry if I was just noise. I thought it was good input! -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface" http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: OGAWA Hirofumi on 24 May 2010 14:20 Jens Axboe <jens.axboe(a)oracle.com> writes: >> > Isn't that pretty much what I described? >> >> Yes, probably. Well, 120kb was still multiple of page size. :) > > It is, but 120KB/page_size is not (which is the power-of-2 of interest > here). Um... I have no interest whether rounded-up-size is power-of-2 or not. Because it is implementation detail. Anyway, we agreed with "in bytes" and "at least"? If so, I'm happy with it, and I'm sorry if I was just noise. -- OGAWA Hirofumi <hirofumi(a)mail.parknet.co.jp> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Michael Kerrisk on 25 May 2010 00:10 On Mon, May 24, 2010 at 7:56 PM, Jens Axboe <jens.axboe(a)oracle.com> wrote: > On Mon, May 24 2010, Michael Kerrisk wrote: >> On Mon, May 24, 2010 at 7:35 PM, Jens Axboe <jens.axboe(a)oracle.com> wrote: >> > On Mon, May 24 2010, Michael Kerrisk wrote: >> >> > Right, that looks like a thinko. >> >> > >> >> > I'll submit a patch changing it to bytes and the agreed API and fix this >> >> > -Eerror. Thanks for your comments and suggestions! >> >> >> >> Thanks. And of course you are welcome. (Please CC linux-api(a)vger on >> >> this patche (and all patches that change the API/ABI.) >> > >> > The first change is this: >> > >> > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=0191f8697bbdfefcd36e7b8dc3eeddfe82893e4b >> > >> > and the one dealing with the pages vs bytes API is this: >> > >> > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=b9598db3401282bb27b4aef77e3eee12015f7f29 >> > >> > Not tested yet, will do so before sending in of course. >> >> Eyeballing it quickly, these changes look right. > > Good, thanks. > >> Do you have some test programs you can make available? > > Actually I don't, I test it by modifying fio's splice engine to set/get > the pipe size and test the resulting transfers. Two more questions: is the rationale for this feature written up somewhere? I could not find it. Is it primarily intended for splice/vmsplice/tee, with the effect for pipe(2) being a side effect? Also, the minuimum size of the buffer is 2 pages. Why is it not 1? (Notwithstanding Linus's assertion, a buffer size of 1 page did give us POSIX compliance in kernels before 2.6.10.) Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface" http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Michael Kerrisk on 27 May 2010 02:50
Jens, On Mon, May 24, 2010 at 7:56 PM, Jens Axboe <jens.axboe(a)oracle.com> wrote: > On Mon, May 24 2010, Michael Kerrisk wrote: >> On Mon, May 24, 2010 at 7:35 PM, Jens Axboe <jens.axboe(a)oracle.com> wrote: >> > On Mon, May 24 2010, Michael Kerrisk wrote: >> >> > Right, that looks like a thinko. >> >> > >> >> > I'll submit a patch changing it to bytes and the agreed API and fix this >> >> > -Eerror. Thanks for your comments and suggestions! >> >> >> >> Thanks. And of course you are welcome. (Please CC linux-api(a)vger on >> >> this patche (and all patches that change the API/ABI.) >> > >> > The first change is this: >> > >> > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=0191f8697bbdfefcd36e7b8dc3eeddfe82893e4b >> > >> > and the one dealing with the pages vs bytes API is this: >> > >> > http://git.kernel.dk/?p=linux-2.6-block.git;a=commit;h=b9598db3401282bb27b4aef77e3eee12015f7f29 >> > >> > Not tested yet, will do so before sending in of course. >> >> Eyeballing it quickly, these changes look right. > > Good, thanks. > >> Do you have some test programs you can make available? > > Actually I don't, I test it by modifying fio's splice engine to set/get > the pipe size and test the resulting transfers. An afterthought. Do there not also need to be fixes to the /proc interfaces. I don't think they were included in your revised patches. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface" http://blog.man7.org/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |