KMALLOC_MAX_SIZE is too big, it easily cause memory fragmented and low memory when param_kernel->data_size is also big. That's not nice. So use vmalloc instead of kmalloc when size is larger than (PAGE_SIZE << 2). There are other drivers using kmalloc to gain a big size memory. And that cause our devices to hit hang and many worse issues. We don't benefit much when using kmalloc in such scenario.
Signed-off-by: xinhui.pan <[email protected]> Signed-off-by: yanmin.zhang <[email protected]> --- drivers/md/dm-ioctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 5152142..31c3af9 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -1709,7 +1709,7 @@ static int copy_params(struct dm_ioctl __user *user, struct dm_ioctl *param_kern * Use kmalloc() rather than vmalloc() when we can. */ dmi = NULL; - if (param_kernel->data_size <= KMALLOC_MAX_SIZE) { + if (param_kernel->data_size <= (PAGE_SIZE << 2)) { dmi = kmalloc(param_kernel->data_size, GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); if (dmi) *param_flags |= DM_PARAMS_KMALLOC; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
