|author||Srijan Sivakumar <firstname.lastname@example.org>||2020-06-02 16:47:24 +0530|
|committer||MOHIT AGRAWAL <email@example.com>||2020-09-17 12:10:58 +0000|
glusterd:Reducing file operations when writing options into volfile.
Issue: The options to be written into the volfile are in form of key-value pairs and the current approach taken to write them into a file is to invoke the write syscall for each key-value pair. This implies an increased number of system calls. Code Changes: 1. Addition of a structure, glusterd_volinfo_data_store_t in glusterd-store.h, containing a character buffer, a pointer to gf_store_handle_t, the current length of data in the buffer as well as a flag for checking key while storing in the buffer. This is used for passing the required file descriptor as well having a character buffer for storing multiple options before being written into a file. 2. Modification of function, _storeopts in glusterd-store.c, which now invokes the gf_store_save_items when buffer is to be emptied into the volfile before further write into it. Also, it has replaced the function _storeslaves, _gd_store_rebalance_dict and _store_global_opts. 3. Modification of function, glusterd_store_volinfo_write in glusterd-store.c, wherein a pointer of type glusterd_volinfo_data_store_t is initialized for further operation. Also, the buffer is emptied into the volfile before it is freed. 4. Modification of function, glusterd_store_node_state_write in glusterd-store.c, wherein the a pointer of type glusterd_volinfo_data_store_t is initialized for further operations. Also, the buffer is emptied into the volfile before it is freed. 5. Addition of enum into glusterd-mem-types.h 6. Modification of function, glusterd_store_options in glusterd-store.c, wherein a pointer of type glusterd_volinfo_data_store_t is initialized for further opertaions. Also, the buffer is emptied into the volfile before it is freed. Reasoning behind the approach: 1.Instead of a dynamic allocation of buffer or increasing the buffer size with increased number of options, it, the current approach takes a buffer of fixed size (VOLINFO_BUFFER_SIZE). Before any write into the buffer, the size is checked and if it exceeds the available space, the contents of the buffer are written to the file before copying new contents. Dynamic allocation can lead to increased memory usage as one doesn't know the number of options that could be added in time and may go on to occupy more space than mandated. 2.The function dict_foreach is a generic function used across different modules. It made sense not to change its implementation as it might affect other Functionalities. Hence a structure was added which could just be passed as one of the parameter to this function (as it takes a void*). 3. Reduced number of system calls implies an increase in execution speed. Also, these modified functions come into play whenever the volume is started or modified. 4. The functions _storeslaves, _gd_store_rebalace_dict and _store_global_opts were doing the same set of operations as that of _storeopts except the checking for the key. This has been handled with the help of a flag in the glusterd_volinfo_data_store_t structure. This reduces the duplicate code present. Signed-off-by: Srijan Sivakumar <firstname.lastname@example.org> Change-Id: I22e6e91c78ed51e3a171482054d77bf793b9ab16 Fixes: #718
Diffstat (limited to 'tests')
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