On 10/30/24 8:02 PM, Johannes Thumshirn wrote: > From: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> > > We have two reports of failed memory allocation in btrfs' code which is > calling into report zones. > > Both of these reports have the following signature coming from > __vmalloc_area_node(): > > kworker/u17:5: vmalloc error: size 0, failed to allocate pages, mode:0x10dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NORETRY|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0 > > Further debugging showed these where allocations of one sector (512 bytes) > and at least one of the reporter's systems where low on memory, so going > through the overhead of allocating a vm area failed. > > Switching the allocation from __vmalloc() to kvzalloc() avoids the > overhead of vmalloc() on small allocations and succeeds. > > Note: the buffer is already freed using kvfree() so there's no need to > adjust the free path. > > Cc: Qu Wenru <wqu@xxxxxxxx> > Cc: Naohiro Aota <naohiro.aota@xxxxxxx> > Link: https://github.com/kdave/btrfs-progs/issues/779 > Link: https://github.com/kdave/btrfs-progs/issues/915 > Fixes: Fixes: 23a50861adda ("scsi: sd_zbc: Cleanup sd_zbc_alloc_report_buffer()") > Signed-off-by: Johannes Thumshirn <johannes.thumshirn@xxxxxxx> Looks good. Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx> -- Damien Le Moal Western Digital Research
