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authorMikulas Patocka <mpatocka@redhat.com>2012-12-21 20:23:36 +0000
committerAlasdair G Kergon <agk@redhat.com>2012-12-21 20:23:36 +0000
commit9c5091f2eeeffe5eca2ffe8a1bc28d312c8a5083 (patch)
tree8452b7ece373cf845bd745ff78750ae325a881d3 /include/linux/device-mapper.h
parent5023e5cf58e1dae904e2e8b5b9779c33512b75a1 (diff)
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dm ioctl: use kmalloc if possible
If the parameter buffer is small enough, try to allocate it with kmalloc() rather than vmalloc(). vmalloc is noticeably slower than kmalloc because it has to manipulate page tables. In my tests, on PA-RISC this patch speeds up activation 13 times. On Opteron this patch speeds up activation by 5%. This patch introduces a new function free_params() to free the parameters and this uses new flags that record whether or not vmalloc() was used and whether or not the input buffer must be wiped after use. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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