Currently mlock() holds mmap_sem in exclusive mode while the pages get faulted in. In the case of a large mlock, this can potentially take a very long time, during which various commands such as 'ps auxw' will block. This makes sysadmins unhappy: real 14m36.232s user 0m0.003s sys 0m0.015s (output from 'time ps auxw' while a 20GB file was being mlocked without being previously preloaded into page cache) I propose that mlock() could release mmap_sem after the VM_LOCKED bits have been set in all appropriate VMAs. Then a second pass could be done to actually mlock the pages, in small batches, releasing mmap_sem when we block on disk access or when we detect some contention. Patches are against v2.6.37-rc4 plus my patches to avoid mlock dirtying (presently queued in -mm). Michel Lespinasse (6): mlock: only hold mmap_sem in shared mode when faulting in pages mm: add FOLL_MLOCK follow_page flag. mm: move VM_LOCKED check to __mlock_vma_pages_range() rwsem: implement rwsem_is_contended() mlock: do not hold mmap_sem for extended periods of time x86 rwsem: more precise rwsem_is_contended() implementation arch/alpha/include/asm/rwsem.h | 5 + arch/ia64/include/asm/rwsem.h | 5 + arch/powerpc/include/asm/rwsem.h | 5 + arch/s390/include/asm/rwsem.h | 5 + arch/sh/include/asm/rwsem.h | 5 + arch/sparc/include/asm/rwsem.h | 5 + arch/x86/include/asm/rwsem.h | 35 ++++++--- arch/x86/lib/rwsem_64.S | 4 +- arch/x86/lib/semaphore_32.S | 4 +- arch/xtensa/include/asm/rwsem.h | 5 + include/linux/mm.h | 1 + include/linux/rwsem-spinlock.h | 1 + lib/rwsem-spinlock.c | 12 +++ mm/internal.h | 3 +- mm/memory.c | 54 ++++++++++++-- mm/mlock.c | 150 ++++++++++++++++++-------------------- mm/nommu.c | 6 +- 17 files changed, 201 insertions(+), 104 deletions(-) -- 1.7.3.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>