[logging] log available memory on startup

Summary: As per title.

Reviewed By: mityal

Differential Revision: D17422964

fbshipit-source-id: 7791b0c87

infer/src/base/ProcessPool.ml

@@ -173,41 +173,21 @@ let send_work_to_child pool slot =
          marshal_to_pipe down_pipe (Do x) )
 
 
-let proc_meminfo = "/proc/meminfo"
-
 (* this should not be called in any other arch than Linux *)
 let should_throttle =
-  Option.iter Config.oom_threshold ~f:(fun _threshold ->
-      match Sys.file_exists proc_meminfo with
-      | `Yes ->
-          ()
-      | _ ->
-          L.die UserError "Can't access %s even though oom detection was requested." proc_meminfo
-  ) ;
   let currently_throttled = ref false in
-  let get_available_memory_MB () =
-    let rec aux in_channel =
-      match In_channel.input_line in_channel with
-      | None ->
-          L.die UserError
-            "Cannot find available memory line in %s even though oom detection was requested."
-            proc_meminfo
-      | Some line -> (
-        try Scanf.sscanf line "MemAvailable: %u kB" (fun mem_kB -> mem_kB / 1024)
-        with Scanf.Scan_failure _ -> aux in_channel )
-    in
-    Utils.with_file_in proc_meminfo ~f:aux
-  in
   fun threshold ->
-    let available_memory = get_available_memory_MB () in
-    if available_memory < threshold then (
+    ( match Utils.get_available_memory_MB () with
+    | None ->
+        L.die UserError "Can't obtain available memory even though oom detection was requested.@."
+    | Some available_memory when available_memory < threshold ->
         if not !currently_throttled then
           L.user_warning
             "Available memory (%d MB) is below configured threshold, throttling back scheduling \
              analysis work.@."
             available_memory ;
-      currently_throttled := true )
-    else (
+        currently_throttled := true
+    | Some available_memory ->
         if !currently_throttled then
           L.user_warning
             "Available memory (%d MB) exceeds configured threshold, resuming scheduling analysis \

infer/src/base/Utils.ml

@@ -404,3 +404,17 @@ let do_in_dir ~dir ~f =
   let cwd = Unix.getcwd () in
   Unix.chdir dir ;
   try_finally_swallow_timeout ~f ~finally:(fun () -> Unix.chdir cwd)
+
+
+let get_available_memory_MB () =
+  let proc_meminfo = "/proc/meminfo" in
+  let rec scan_for_expected_output in_channel =
+    match In_channel.input_line in_channel with
+    | None ->
+        None
+    | Some line -> (
+      try Scanf.sscanf line "MemAvailable: %u kB" (fun mem_kB -> Some (mem_kB / 1024))
+      with Scanf.Scan_failure _ -> scan_for_expected_output in_channel )
+  in
+  if Sys.file_exists proc_meminfo <> `Yes then None
+  else with_file_in proc_meminfo ~f:scan_for_expected_output

infer/src/base/Utils.mli

@@ -139,3 +139,7 @@ val timeit : f:(unit -> 'a) -> 'a * int
 
 val do_in_dir : dir:string -> f:(unit -> 'a) -> 'a
 (** executes [f] after cding into [dir] and then restores original cwd *)
+
+val get_available_memory_MB : unit -> int option
+(** On Linux systems, return [Some x] where [MemAvailable x] is in [/proc/meminfo].
+    Returns [None] in all other cases. *)

infer/src/infer.ml

@@ -90,8 +90,14 @@ let log_environment_info () =
     |> Option.map ~f:(String.split ~on:CLOpt.env_var_sep)
     |> Option.value ~default:["<not set>"]
   in
-  L.environment_info "INFER_ARGS = %a" Pp.cli_args infer_args ;
-  L.environment_info "command line arguments: %a" Pp.cli_args (Array.to_list Sys.argv) ;
+  L.environment_info "INFER_ARGS = %a@\n" Pp.cli_args infer_args ;
+  L.environment_info "command line arguments: %a@\n" Pp.cli_args (Array.to_list Sys.argv) ;
+  ( match Utils.get_available_memory_MB () with
+  | None ->
+      L.environment_info "Could not retrieve available memory (possibly not on Linux)@\n"
+  | Some available_memory ->
+      L.environment_info "Available memory at startup: %d MB@\n" available_memory ;
+      ScubaLogging.log_count ~label:"startup_mem_avail_MB" ~value:available_memory ) ;
   print_active_checkers ()