Messages in this thread | | | Date | Thu, 12 Oct 2006 08:32:43 +0200 | From | Eric Dumazet <> | Subject | Re: [PATCH] fdtable: Eradicate fdarray overflow. |
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Vadim Lobanov a écrit : > On Wednesday 11 October 2006 22:19, Eric Dumazet wrote: >> Hi Vadim >> >> I find your PAGE_SIZE/4 minimum allocation quite unjustified. >> >> For architectures with 64K PAGE_SIZE, we endup allocating 16K, for poor >> tasks that happen to touch a not so high (>= 64) file descriptor... >> >> I would vote for a fixed size, like 1024 > > In my opinion, always picking 1024 would be highly suboptimal for some > architectures (x86-64 in particular -- that's a whole page, just for the > fdarray!). If anything, I'd prefer something similar to this pseudo-code:
I was speaking of 1024 bytes.
I was the guy who made fdset going from PAGE_SIZE to 64 bytes (L1_CACHE_BYTES if you dare), I wont be the guy responsible for a reverse path on fdtable :)
That is replace your (PAGE_SIZE/4) by 1024, wich was you probably meant No archi has a smaller page, so no need to play with min_t() macro...
> > #define FDTABLE_MIN min_t(uint, PAGE_SIZE / 4 / sizeof(struct file *), 1024) > ... > nr /= FDTABLE_MIN; > nr = roundup_pow_of_two(nr + 1); > nr *= FDTABLE_MIN; > > gcc should be smart enough to optimize that expression into a single constant. > At least it did (version 4.1.0) in my quick test here. > >> Eric > > Let me know what you think. Please don't just go radio-silent on me. ;) >
radio-silent ? well, it seems I already sent you many mails about your patches :)
Eric
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