Messages in this thread | | | Date | Wed, 26 Apr 2006 11:12:48 +0200 | From | Jes Sorensen <> | Subject | Re: [PATCH] change gen_pool allocator to not touch managed memory |
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Dean Nelson wrote: >>> Both Andrey Volkov and Jes Sorensen have expressed a desire that the >>> gen_pool allocator not write to the memory being managed. See the >>> following: >>> >>> http://marc.theaimsgroup.com/?l=linux-kernel&m=113518602713125&w=2 >>> http://marc.theaimsgroup.com/?l=linux-kernel&m=113533568827916&w=2 >> hm, fair enough. >> >> The patch is fairly large+intrusive. I trust it's been broadly tested? > > Yes, it was thoroughly tested. I even pulled the bitmap manipulation code > into a user app with which I could pre-set bits of a bitmap in order to > test boundary conditions with various contiguous bit lengths.
I haven't been directly involved in this work, but I am very confident in Dean's work in this.
Just a few minor nits below:
> -unsigned long gen_pool_alloc(struct gen_pool *poolp, int size) > +int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size, > + int nid) > { > - int j, i, s, max_chunk_size; > - unsigned long a, flags; > - struct gen_pool_link *h = poolp->h; > + struct gen_pool_chunk *chunk; > + int nbits = size >> pool->min_alloc_order; > + int nbytes = sizeof(struct gen_pool_chunk) + > + (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE; > + > + if (nbytes > PAGE_SIZE) { > + chunk = vmalloc_node(nbytes, nid); > + } else { > + chunk = kmalloc_node(nbytes, GFP_KERNEL, nid); > + }
Any patch that adds vmalloc() calls to code always makes the little hairs on the back of my neck stand up. Any chance we could get away with alloc_pages_node() for this?
> ia64_pal_mc_drain(); > - status = smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1); > - if (status) > - printk(KERN_WARNING "smp_call_function failed for " > - "uncached_ipi_mc_drain! (%i)\n", status); > + (void) smp_call_function(uncached_ipi_mc_drain, NULL, 0, 1);
This thing could in theory fail so having the error check there seems the right thing to me. In either case, please don't (void) the function return (this is a style issue, I know).
> Index: linux-2.6/arch/ia64/sn/kernel/sn2/cache.c > =================================================================== > --- linux-2.6.orig/arch/ia64/sn/kernel/sn2/cache.c 2006-04-24 12:25:36.234717101 -0500 > +++ linux-2.6/arch/ia64/sn/kernel/sn2/cache.c 2006-04-24 12:27:56.012899026 -0500
This part we should maybe do in a seperate patch? It seems valid on it's own?
Cheers, Jes - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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