Messages in this thread | | | Date | Thu, 09 Aug 2012 18:12:39 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: [RFC PATCH 1/6] virtio/console: Add splice_write support |
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(2012/08/09 18:00), Amit Shah wrote: > On (Tue) 24 Jul 2012 [11:37:07], Yoshihiro YUNOMAE wrote: >> From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> >> >> Enable to use splice_write from pipe to virtio-console port. >> This steals pages from pipe and directly send it to host. >> >> Note that this may accelerate only the guest to host path. >> >> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> >> Cc: Amit Shah <amit.shah@redhat.com> >> Cc: Arnd Bergmann <arnd@arndb.de> >> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >> --- > >> +/* Faster zero-copy write by splicing */ >> +static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe, >> + struct file *filp, loff_t *ppos, >> + size_t len, unsigned int flags) >> +{ >> + struct port *port = filp->private_data; >> + struct sg_list sgl; >> + ssize_t ret; >> + struct splice_desc sd = { >> + .total_len = len, >> + .flags = flags, >> + .pos = *ppos, >> + .u.data = &sgl, >> + }; >> + >> + sgl.n = 0; >> + sgl.len = 0; >> + sgl.sg = kmalloc(sizeof(struct scatterlist) * MAX_SPLICE_PAGES, >> + GFP_ATOMIC); > > Do you expect this function to be called from interrupt context?
No, not at all. Oops, that should be GFP_KERNEL...
Thank you for pointing it out.
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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