Re: [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 22-Feb-21 10:41 AM, Roy Shterman wrote:
> When using huge_unlink we unlink the segment right
> after allocation. Although we unlink the file we keep
> the fd in fd_list so file still exist just the path deleted.
> When freeing the hugepage we need to close the fd and assign
> it with (-1) in fd_list for the page to be released.
> 
> The current flow fails rte_malloc in the following flow when working
> with --huge-unlink option:
> 1. alloc_seg() for segment A -
>      We allocate segment, unlink the path to the segment
>      and keep the file descriptor in fd_list.
> 2. free_seg() for segment A -
>      We clear the segment metadata and return - without closing fd
>      or assigning (-1) in fd list.
> 3. alloc_seg() for segment A again -
>      We find segment A as available, try to allocate it,
>      find the old fd in fd_list try to unlink it
>      as part of alloc_seg() but failed because path doesn't exist.
> 
> The impact of such error is falsly failing rte_malloc()
> although we have hugepages available.
> 
> Fixes: d435aad37da7 ("mem: support --huge-unlink mode")
> 
> Signed-off-by: Roy Shterman <roy.shterman@vastdata.com>
> ---

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

-- 
Thanks,
Anatoly