On 3/29/19 9:48 AM, Yafang Shao wrote: > On Fri, Mar 29, 2019 at 4:45 PM Vlastimil Babka <vbabka@xxxxxxx> wrote: >> >> On 3/29/19 9:36 AM, Yafang Shao wrote: >>> direct_compaction is not initialized for kcompactd or manually triggered >>> compaction (via /proc or /sys). >> >> It doesn't need to, this style of initialization does guarantee that any >> field not explicitly mentioned is initialized to 0/NULL/false... and >> this pattern is used all over the kernel. >> > > Hmm. > You mean the gcc will set the local variable to 0 ? Not local variable, but fields omitted in this "designated initializers" scenario. > Are there any reference to this behavior ? https://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html "Omitted fields are implicitly initialized the same as for objects that have static storage duration. " and static objects are implicitly 0
