• Kyeongdon Kim's avatar
    zram: try vmalloc() after kmalloc() · 75b79536
    Kyeongdon Kim authored
    commit d913897a upstream.
    
    When we're using LZ4 multi compression streams for zram swap, we found
    out page allocation failure message in system running test.  That was
    not only once, but a few(2 - 5 times per test).  Also, some failure
    cases were continually occurring to try allocation order 3.
    
    In order to make parallel compression private data, we should call
    kzalloc() with order 2/3 in runtime(lzo/lz4).  But if there is no order
    2/3 size memory to allocate in that time, page allocation fails.  This
    patch makes to use vmalloc() as fallback of kmalloc(), this prevents
    page alloc failure warning.
    
    After using this, we never found warning message in running test, also
    It could reduce process startup latency about 60-120ms in each case.
    
    For reference a call trace :
    
        Binder_1: page allocation failure: order:3, mode:0x10c0d0
        CPU: 0 PID: 424 Comm: Binder_1 Tainted: GW 3.10.49-perf-g991d02b-dirty #20
        Call trace:
          dump_backtrace+0x0/0x270
          show_stack+0x10/0x1c
          dump_stack+0x1c/0x28
          warn_alloc_failed+0xfc/0x11c
          __alloc_pages_nodemask+0x724/0x7f0
          __get_free_pages+0x14/0x5c
          kmalloc_order_trace+0x38/0xd8
          zcomp_lz4_create+0x2c/0x38
          zcomp_strm_alloc+0x34/0x78
          zcomp_strm_multi_find+0x124/0x1ec
          zcomp_strm_find+0xc/0x18
          zram_bvec_rw+0x2fc/0x780
          zram_make_request+0x25c/0x2d4
          generic_make_request+0x80/0xbc
          submit_bio+0xa4/0x15c
          __swap_writepage+0x218/0x230
          swap_writepage+0x3c/0x4c
          shrink_page_list+0x51c/0x8d0
          shrink_inactive_list+0x3f8/0x60c
          shrink_lruvec+0x33c/0x4cc
          shrink_zone+0x3c/0x100
          try_to_free_pages+0x2b8/0x54c
          __alloc_pages_nodemask+0x514/0x7f0
          __get_free_pages+0x14/0x5c
          proc_info_read+0x50/0xe4
          vfs_read+0xa0/0x12c
          SyS_read+0x44/0x74
        DMA: 3397*4kB (MC) 26*8kB (RC) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB
             0*512kB 0*1024kB 0*2048kB 0*4096kB = 13796kB
    
    [minchan@kernel.org: change vmalloc gfp and adding comment about gfp]
    [sergey.senozhatsky@gmail.com: tweak comments and styles]
    Signed-off-by: default avatarKyeongdon Kim <kyeongdon.kim@lge.com>
    Signed-off-by: default avatarMinchan Kim <minchan@kernel.org>
    Acked-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
    Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
    75b79536
zcomp_lzo.c 1.7 KB