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    SubjectRe: O_DIRECT question
    On 1/11/07, Aubrey <> wrote:
    > Firstly I want to say I'm working on no-mmu arch and uClinux.
    > After much of file operations VFS cache eat up all of the memory.
    > At this time, if an application request memory which order > 3, the
    > kernel will report failure.
    > uClinux use a memory mapped MTD driver to store rootfs, of course it's
    > in the ram,
    > So I don't need VFS cache to improve performance. And when order > 3,
    > __alloc_page() even doesn't try to shrunk cache and slab, just report
    > failure.
    > So my thought is remove cache, or limit it. But currently there seems
    > to be no way in the kernel to do it. So I want to try to use
    > O_DIRECT. But it seems not to be a right way.
    One possibility might be to poke the open method in struct
    file_operations of your fs like

    static int my_open_file(struct inode *inode, struct file *filp)
    filp->f_flags |= O_DIRECT;

    which is a nasty thing to do but might give you an idea of what happens next.

    I like long walks, especially when they are taken by people who annoy me.
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      Last update: 2007-01-11 07:45    [W:0.021 / U:83.840 seconds]
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