From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shakeel Butt Subject: [PATCH v2 1/4] memcg: refactor mem_cgroup_oom Date: Thu, 10 Feb 2022 22:49:14 -0800 Message-ID: <20220211064917.2028469-2-shakeelb@google.com> References: <20220211064917.2028469-1-shakeelb@google.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=nDUa4nh0VfMB33PiEe/+b8nW+DWgiuCX8+o5RVf1oHI=; b=ThzYMOIDPOykUabiB3RlRAijrJSIHNXOSUgcmlKL4c2HDkyKp7qaJwrCrOB5Cj7/Sn b+6g0BlcsH3JRNO1HyBb0LIliKk840gqIqgFjHZyfba+0Rzygu2PqymxQgM8gR9yQfI2 UsYHiVjl75cre377AqUX4YDmZQbFTuUf3922omgktt3jvQUKmwr3eB7X7/Z19Ju1H4ex PjrES1T9lJwMXV5jyWjXRhmiR+2EhxtUnHDoQdtmgniawP0Vl+SgjVunv4BNLBp8DepV bZ7c1Ro3WZr7RdhwOGLkLCIGOQPDT8YXV3AJpris0GtceJxuIoOltOYgpfluZ3rotD5S G5vg== In-Reply-To: <20220211064917.2028469-1-shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Johannes Weiner , Michal Hocko , Roman Gushchin Cc: Chris Down , Andrew Morton , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Shakeel Butt The function mem_cgroup_oom returns enum which has four possible values but the caller does not care about such values and only cares if the return value is OOM_SUCCESS or not. So, remove the enum altogether and make mem_cgroup_oom returns a simple bool. Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin --- Changes since v1: - Added comment for mem_cgroup_oom as suggested by Roman mm/memcontrol.c | 44 +++++++++++++++++--------------------------- 1 file changed, 17 insertions(+), 27 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a0e9d9f12cf5..f12e489ba9b8 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1795,20 +1795,16 @@ static void memcg_oom_recover(struct mem_cgroup *memcg) __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } -enum oom_status { - OOM_SUCCESS, - OOM_FAILED, - OOM_ASYNC, - OOM_SKIPPED -}; - -static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) +/* + * Returns true if successfully killed one or more processes. Though in some + * corner cases it can return true even without killing any process. + */ +static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order) { - enum oom_status ret; - bool locked; + bool locked, ret; if (order > PAGE_ALLOC_COSTLY_ORDER) - return OOM_SKIPPED; + return false; memcg_memory_event(memcg, MEMCG_OOM); @@ -1831,14 +1827,13 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int * victim and then we have to bail out from the charge path. */ if (memcg->oom_kill_disable) { - if (!current->in_user_fault) - return OOM_SKIPPED; - css_get(&memcg->css); - current->memcg_in_oom = memcg; - current->memcg_oom_gfp_mask = mask; - current->memcg_oom_order = order; - - return OOM_ASYNC; + if (current->in_user_fault) { + css_get(&memcg->css); + current->memcg_in_oom = memcg; + current->memcg_oom_gfp_mask = mask; + current->memcg_oom_order = order; + } + return false; } mem_cgroup_mark_under_oom(memcg); @@ -1849,10 +1844,7 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int mem_cgroup_oom_notify(memcg); mem_cgroup_unmark_under_oom(memcg); - if (mem_cgroup_out_of_memory(memcg, mask, order)) - ret = OOM_SUCCESS; - else - ret = OOM_FAILED; + ret = mem_cgroup_out_of_memory(memcg, mask, order); if (locked) mem_cgroup_oom_unlock(memcg); @@ -2545,7 +2537,6 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, int nr_retries = MAX_RECLAIM_RETRIES; struct mem_cgroup *mem_over_limit; struct page_counter *counter; - enum oom_status oom_status; unsigned long nr_reclaimed; bool passed_oom = false; bool may_swap = true; @@ -2648,9 +2639,8 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, * a forward progress or bypass the charge if the oom killer * couldn't make any progress. */ - oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask, - get_order(nr_pages * PAGE_SIZE)); - if (oom_status == OOM_SUCCESS) { + if (mem_cgroup_oom(mem_over_limit, gfp_mask, + get_order(nr_pages * PAGE_SIZE))) { passed_oom = true; nr_retries = MAX_RECLAIM_RETRIES; goto retry; -- 2.35.1.265.g69c8d7142f-goog