On Tue 07-11-17 08:03:27, Joe Perches wrote: > On Tue, 2017-11-07 at 16:43 +0100, Michal Hocko wrote: > > On Tue 07-11-17 07:34:25, Joe Perches wrote: > [] > > > I believe, but have not tested, that using a specific width > > > as an argument to %*pb[l] will constrain the number of > > > spaces before the '(null)' output in any NULL pointer use. > > > > > > So how about a #define like > > > > > > /* > > > * nodemask_pr_args is only used with a "%*pb[l]" format for a nodemask. > > > * A NULL nodemask uses 6 to emit "(null)" without leading spaces. > > > */ > > > #define nodemask_pr_args(maskp) \ > > > (maskp) ? MAX_NUMNODES : 6, \ > > > (maskp) ? (maskp)->bits : NULL > > > > Why not -1 then? > > I believe it's the field width and not the precision that > needs to be set. But the first of the two arguments is the field with specifier, not the precision. /me confused... Anyway, the following works as expected when printing the OOM report: [ 47.005321] mem_eater invoked oom-killer: gfp_mask=0x14280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null), order=0, oom_score_adj=0 [ 47.007183] mem_eater cpuset=/ mems_allowed=0-1 [ 47.007829] CPU: 3 PID: 3223 Comm: mem_eater Tainted: G W 4.13.0-pr1-dirty #11 I hope I haven't overlooked anything --- >From 35aa7742d35d29af88c66dd5e6f8f5d62215f5fd Mon Sep 17 00:00:00 2001 From: Michal Hocko <mhocko@xxxxxxxx> Date: Thu, 9 Nov 2017 10:58:41 +0100 Subject: [PATCH] mm: simplify nodemask printing alloc_warn and dump_header have to explicitly handle NULL nodemask which forces both paths to use pr_cont. We can do better. printk already handles NULL pointers properly so all what we need is to teach nodemask_pr_args to handle NULL nodemask carefully. This allows simplification of both alloc_warn and dump_header and get rid of pr_cont altogether. This patch has been motivated by patch from Joe Perches http://lkml.kernel.org/r/b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@xxxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> --- include/linux/nodemask.h | 2 +- mm/oom_kill.c | 12 ++++-------- mm/page_alloc.c | 12 +++--------- 3 files changed, 8 insertions(+), 18 deletions(-) diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index cf0b91c3ec12..5d3cc67207ed 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -103,7 +103,7 @@ extern nodemask_t _unused_nodemask_arg_; * * Can be used to provide arguments for '%*pb[l]' when printing a nodemask. */ -#define nodemask_pr_args(maskp) MAX_NUMNODES, (maskp)->bits +#define nodemask_pr_args(maskp) (maskp) ? MAX_NUMNODES : 0, (maskp) ? (maskp)->bits : NULL /* * The inline keyword gives the compiler room to decide to inline, or diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 8dd0e088189b..606213a81ceb 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -426,14 +426,10 @@ static void dump_tasks(struct mem_cgroup *memcg, const nodemask_t *nodemask) static void dump_header(struct oom_control *oc, struct task_struct *p) { - pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=", - current->comm, oc->gfp_mask, &oc->gfp_mask); - if (oc->nodemask) - pr_cont("%*pbl", nodemask_pr_args(oc->nodemask)); - else - pr_cont("(null)"); - pr_cont(", order=%d, oom_score_adj=%hd\n", - oc->order, current->signal->oom_score_adj); + pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=%*pbl, order=%d, oom_score_adj=%hd\n", + current->comm, oc->gfp_mask, &oc->gfp_mask, + nodemask_pr_args(oc->nodemask), oc->order, + current->signal->oom_score_adj); if (!IS_ENABLED(CONFIG_COMPACTION) && oc->order) pr_warn("COMPACTION is disabled!!!\n"); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d755434aee94..457e43ed4c10 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3281,20 +3281,14 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask, const char *fmt, ...) if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs)) return; - pr_warn("%s: ", current->comm); - va_start(args, fmt); vaf.fmt = fmt; vaf.va = &args; - pr_cont("%pV", &vaf); + pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl\n", + current->comm, &vaf, gfp_mask, &gfp_mask, + nodemask_pr_args(nodemask)); va_end(args); - pr_cont(", mode:%#x(%pGg), nodemask=", gfp_mask, &gfp_mask); - if (nodemask) - pr_cont("%*pbl\n", nodemask_pr_args(nodemask)); - else - pr_cont("(null)\n"); - cpuset_print_current_mems_allowed(); dump_stack(); -- 2.14.2 -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
