v1->v2: - Address feedbacks from PeterZ and Andi Kleen. This patchset introduces a simple list insertion/deletion batching facility to batch multiple list insertion and deletion operations into a single one under one lock/unlock critical section. Patch 1 introduces this new facility. Patch 2 enables it for the x86 architecture. Patch 3 makes the insertion and deletion of the VFS superblock's inode list to use the new list batching functions. On x86-64, the generated code (gcc v4.8.5) of the inode_sb_list_add() function without the patch was: 0x0000000000001030 <+0>: callq 0x1035 <inode_sb_list_add+5> 0x0000000000001035 <+5>: push %rbp 0x0000000000001036 <+6>: mov %rsp,%rbp 0x0000000000001039 <+9>: push %rbx 0x000000000000103a <+10>: mov 0x28(%rdi),%rax 0x000000000000103e <+14>: mov %rdi,%rbx 0x0000000000001041 <+17>: lea 0x600(%rax),%rdi 0x0000000000001048 <+24>: callq 0x104d <inode_sb_list_add+29> 0x000000000000104d <+29>: mov 0x28(%rbx),%rsi 0x0000000000001051 <+33>: lea 0x120(%rbx),%rdi 0x0000000000001058 <+40>: mov 0x608(%rsi),%rdx 0x000000000000105f <+47>: add $0x608,%rsi 0x0000000000001066 <+54>: callq 0x106b <inode_sb_list_add+59> 0x000000000000106b <+59>: mov 0x28(%rbx),%rdi 0x000000000000106f <+63>: add $0x600,%rdi 0x0000000000001076 <+70>: callq *0x0 0x000000000000107d <+77>: pop %rbx 0x000000000000107e <+78>: pop %rbp 0x000000000000107f <+79>: retq With the patch, the function became: 0x0000000000001030 <+0>: callq 0x1035 <inode_sb_list_add+5> 0x0000000000001035 <+5>: push %rbp 0x0000000000001036 <+6>: mov %rsp,%rbp 0x0000000000001039 <+9>: push %r13 0x000000000000103b <+11>: lea 0x120(%rdi),%r13 0x0000000000001042 <+18>: push %r12 0x0000000000001044 <+20>: push %rbx 0x0000000000001045 <+21>: mov 0x28(%rdi),%r12 0x0000000000001049 <+25>: lea 0x600(%r12),%rbx 0x0000000000001051 <+33>: mov %rbx,%rdi 0x0000000000001054 <+36>: callq 0x1059 <inode_sb_list_add+41> 0x0000000000001059 <+41>: test %eax,%eax 0x000000000000105b <+43>: je 0x1081 <inode_sb_list_add+81> 0x000000000000105d <+45>: mov 0x618(%r12),%rsi 0x0000000000001065 <+53>: mov %r13,%rdi 0x0000000000001068 <+56>: mov (%rsi),%rdx 0x000000000000106b <+59>: callq 0x1070 <inode_sb_list_add+64> 0x0000000000001070 <+64>: mov %rbx,%rdi 0x0000000000001073 <+67>: callq *0x0 0x000000000000107a <+74>: pop %rbx 0x000000000000107b <+75>: pop %r12 0x000000000000107d <+77>: pop %r13 0x000000000000107f <+79>: pop %rbp 0x0000000000001080 <+80>: retq 0x0000000000001081 <+81>: lea 0x618(%r12),%rdx 0x0000000000001089 <+89>: mov %r13,%rcx 0x000000000000108c <+92>: mov %rbx,%rsi 0x000000000000108f <+95>: xor %edi,%edi 0x0000000000001091 <+97>: callq 0x1096 <inode_sb_list_add+102> 0x0000000000001096 <+102>: jmp 0x107a <inode_sb_list_add+74> For the fastpath, the only overheads are the testing of the return value of the spin_trylock function and the push/pop of 2 more registers. Other than that, they look very similar. Waiman Long (3): lib/list_batch: A simple list insertion/deletion batching facility lib/list_batch, x86: Enable list insertion/deletion batching for x86 vfs: Enable list batching for the superblock's inode list arch/x86/Kconfig | 1 + fs/inode.c | 13 ++--- fs/super.c | 1 + include/linux/fs.h | 2 + include/linux/list_batch.h | 133 ++++++++++++++++++++++++++++++++++++++++++++ lib/Kconfig | 7 ++ lib/Makefile | 1 + lib/list_batch.c | 125 +++++++++++++++++++++++++++++++++++++++++ 8 files changed, 275 insertions(+), 8 deletions(-) create mode 100644 include/linux/list_batch.h create mode 100644 lib/list_batch.c -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
