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authorHATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>2013-07-03 15:02:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-03 16:07:30 -0700
commit087350c9dcf1b38c597b31d7761f7366e2866e6b (patch)
tree9dddb06c41aba0af9347e3c08d9f64fa3f8c685e /samples
parente69e9d4aee712a22665f008ae0550bb3d7c7f7c1 (diff)
vmcore: allocate ELF note segment in the 2nd kernel vmalloc memory
The reasons why we don't allocate ELF note segment in the 1st kernel (old memory) on page boundary is to keep backward compatibility for old kernels, and that if doing so, we waste not a little memory due to round-up operation to fit the memory to page boundary since most of the buffers are in per-cpu area. ELF notes are per-cpu, so total size of ELF note segments depends on number of CPUs. The current maximum number of CPUs on x86_64 is 5192, and there's already system with 4192 CPUs in SGI, where total size amounts to 1MB. This can be larger in the near future or possibly even now on another architecture that has larger size of note per a single cpu. Thus, to avoid the case where memory allocation for large block fails, we allocate vmcore objects on vmalloc memory. This patch adds elfnotes_buf and elfnotes_sz variables to keep pointer to the ELF note segment buffer and its size. There's no longer the vmcore object that corresponds to the ELF note segment in vmcore_list. Accordingly, read_vmcore() has new case for ELF note segment and set_vmcore_list_offsets_elf{64,32}() and other helper functions starts calculating offset from sum of size of ELF headers and size of ELF note segment. [akpm@linux-foundation.org: use min(), fix error-path vzalloc() leaks] Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp> Cc: Lisa Mitchell <lisa.mitchell@hp.com> Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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