On Sun, 7 December 2008 23:32:32 +0000, Phillip Lougher wrote: > > Currently, as mentioned above, Squashfs decompresses into a single > contiguous output buffer. But, due to the linux kernel mailing list's > dislike of vmalloc, this is being changed. Don't blame lkml, blame Intel and IBM. Back in the days of the 386, a beefy machine had 8MB of physical memory and 4GB of virtual memory space. Noone had to worry about fragmentation anymore. If you needed a 1MB buffer, you'd just round up some 256 pages and instruct the mmu to map them into a large contiguous address range in the virtual address space. Life was good indeed. But physical memory has constantly grown since, while the virtual memory space has for a long time stagnated. Intel even introduced some hardware hacks to use up to 64GB of physical memory with a measly 4GB of virtual memory. Now it was _virtual_ memory fragmentation that you had to worry about. These days most CPUs you'd buy are 64bit, so virtual memory space has become useful again. But as a kernel hacker, you have little control over what hardware everyone is using. And those weird systems with more physical than virtual memory are still around. :( Jörn -- Don't patch bad code, rewrite it. -- Kernigham and Pike, according to Rusty -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
