[Devel] Re: [PATCH 0/6] fuse: allocate req->pages[] dynamically

[Maxim V. Patlasov]

Hi Miklos,

So far as no objections appeared, I'll go ahead and replace fuse 
req->page with req->pagevec. It will point to an array of structs:

struct page_vec {
     struct page    *pv_page;
     unsigned int    pv_len;
     unsigned int    pv_offset;
};

instead of 'struct page *' as it used to be. It seems to be what you 
suggested in one of your comments. Are you OK about it?

Thanks,
Maxim

09/07/2012 09:40 PM, Maxim Patlasov пишет:
> Hi,
>
> Currently, any fuse request always includes inline pages[] array of
> FUSE_MAX_PAGES_PER_REQ elements. This is the waste of memory because
> in many cases smaller size would suffice.
>
> The patch-set tries to allocate only as many elements of pages[] array as
> actaully needed. This will be even more useful in the future because of:
>
> 1. Mitsuo's patches making maximum read/write request size tunable.
> 2. My patches optimizing scatter-gather direct IO. To make them simplier I'll
> need to substitute array of 'struct page *' with array of 'struct bio_vec'.
> It would make memory overhead worse if implemented w/o this patch-set.
>
> Thanks,
> Maxim
>