linux-kernel - [PATCH 2/2] pm: add more logging on hibernation failure

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Message-Id: <20191226220205.128664-3-semenzato@google.com>
Date:   Thu, 26 Dec 2019 14:02:05 -0800
From:   Luigi Semenzato <semenzato@...gle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     rafael@...nel.org, akpm@...ux-foundation.org, gpike@...gle.com,
        Luigi Semenzato <semenzato@...gle.com>
Subject: [PATCH 2/2] pm: add more logging on hibernation failure

Hibernation fails when the kernel cannot allocate enough memory
to copy all pages in use.  This patch ensures that the failure
reason is clearly logged.

Signed-off-by: Luigi Semenzato <semenzato@...gle.com>
---
 kernel/power/snapshot.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 26b9168321e7..df498717a97e 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1705,16 +1705,20 @@ int hibernate_preallocate_memory(void)
 	ktime_t start, stop;
 	int error;
 
-	pr_info("Preallocating image memory... ");
+	pr_info("Preallocating hibernation image memory\n");
 	start = ktime_get();
 
 	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
-	if (error)
+	if (error) {
+		pr_err("Cannot allocate original bitmap\n");
 		goto err_out;
+	}
 
 	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
-	if (error)
+	if (error) {
+		pr_err("Cannot allocate copy bitmap\n");
 		goto err_out;
+	}
 
 	alloc_normal = 0;
 	alloc_highmem = 0;
@@ -1804,8 +1808,11 @@ int hibernate_preallocate_memory(void)
 		alloc -= pages;
 		pages += pages_highmem;
 		pages_highmem = preallocate_image_highmem(alloc);
-		if (pages_highmem < alloc)
+		if (pages_highmem < alloc) {
+			pr_err("Image allocation is %lu pages short\n",
+				alloc - pages_highmem);
 			goto err_out;
+		}
 		pages += pages_highmem;
 		/*
 		 * size is the desired number of saveable pages to leave in
@@ -1836,13 +1843,12 @@ int hibernate_preallocate_memory(void)
 
  out:
 	stop = ktime_get();
-	pr_cont("done (allocated %lu pages)\n", pages);
+	pr_info("Allocated %lu pages for hibernation shapshot\n", pages);
 	swsusp_show_speed(start, stop, pages, "Allocated");
 
 	return 0;
 
  err_out:
-	pr_cont("\n");
 	swsusp_free();
 	return -ENOMEM;
 }
-- 
2.24.1.735.g03f4e72817-goog