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    Subject[PATCH v6 08/16] memcg: enable accounting for pollfd and select bits arrays
    Date
    User can call select/poll system calls with a large number of assigned
    file descriptors and force kernel to allocate up to several pages of memory
    till end of these sleeping system calls. We have here long-living
    unaccounted per-task allocations.

    It makes sense to account for these allocations to restrict the host's
    memory consumption from inside the memcg-limited container.

    Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
    ---
    fs/select.c | 4 ++--
    1 file changed, 2 insertions(+), 2 deletions(-)

    diff --git a/fs/select.c b/fs/select.c
    index 945896d..e83e563 100644
    --- a/fs/select.c
    +++ b/fs/select.c
    @@ -655,7 +655,7 @@ int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
    goto out_nofds;

    alloc_size = 6 * size;
    - bits = kvmalloc(alloc_size, GFP_KERNEL);
    + bits = kvmalloc(alloc_size, GFP_KERNEL_ACCOUNT);
    if (!bits)
    goto out_nofds;
    }
    @@ -1000,7 +1000,7 @@ static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,

    len = min(todo, POLLFD_PER_PAGE);
    walk = walk->next = kmalloc(struct_size(walk, entries, len),
    - GFP_KERNEL);
    + GFP_KERNEL_ACCOUNT);
    if (!walk) {
    err = -ENOMEM;
    goto out_fds;
    --
    1.8.3.1
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