fs: aio: fix the increment of aio-nr and counting against aio-max-nr
Currently, aio-nr is incremented in steps of 'num_possible_cpus() * 8' for io_setup(nr_events, ..) with 'nr_events < num_possible_cpus() * 4': ioctx_alloc() ... nr_events = max(nr_events, num_possible_cpus() * 4); nr_events *= 2; ... ctx->max_reqs = nr_events; ... aio_nr += ctx->max_reqs; .... This limits the number of aio contexts actually available to much less than aio-max-nr, and is increasingly worse with greater number of CPUs. For example, with 64 CPUs, only 256 aio contexts are actually available (with aio-max-nr = 65536) because the increment is 512 in that scenario. Note: 65536 [max aio contexts] / (64*4*2) [increment per aio context] is 128, but make it 256 (double) as counting against 'aio-max-nr * 2': ioctx_alloc() ... if (aio_nr + nr_events > (aio_max_nr * 2UL) || ... goto err_ctx; ... This patch uses the original value of nr_events (from userspace) to increment aio-nr and count against aio-max-nr, which resolves those. Signed-off-by: NMauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Reported-by: NLekshmi C. Pillai <lekshmi.cpillai@in.ibm.com> Tested-by: NLekshmi C. Pillai <lekshmi.cpillai@in.ibm.com> Tested-by: NPaul Nguyen <nguyenp@us.ibm.com> Reviewed-by: NJeff Moyer <jmoyer@redhat.com> Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
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