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PM: hibernate: call preallocate_image() after freeze prepare

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Certain drivers release resources (pinned pages, etc.) into system
memory during the prepare freeze PM op, making them swappable.
Currently, hibernate_preallocate_memory() is called before prepare
freeze, so those drivers have no opportunity to release resources
first. If a driver is holding a large amount of unswappable system
RAM, this can cause hibernate_preallocate_memory() to fail.

Move the call to hibernate_preallocate_memory() after prepare freeze.

According to the documentation for the prepare callback, devices should
be left in a usable state, so storage drivers should still be able to
service I/O requests. This allows drivers to release unswappable
resources prior to preallocation, so they can be swapped out through
hibernate_preallocate_memory()'s reclaim path.

Also remove shrink_shmem_memory() since hibernate_preallocate_memory()
will have reclaimed enough memory for the hibernation image.

Signed-off-by: Matthew Leach <matthew.leach@collabora.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
[ rjw: Subject and changelog tweaks ]
Link: https://patch.msgid.link/20260403-hibernation-fixes-v3-1-31bc9fa3ba2d@collabora.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Matthew Leach
2026-04-03 08:36:30 +01:00
committed by Rafael J. Wysocki
parent 5200f5f493
commit 783c810984
1 changed files with 9 additions and 37 deletions
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46
kernel/power/hibernate.c
View File

@@ -392,23 +392,6 @@ static int create_image(int platform_mode)
return error;
}
static void shrink_shmem_memory(void)
{
struct sysinfo info;
unsigned long nr_shmem_pages, nr_freed_pages;
si_meminfo(&info);
nr_shmem_pages = info.sharedram; /* current page count used for shmem */
/*
* The intent is to reclaim all shmem pages. Though shrink_all_memory() can
* only reclaim about half of them, it's enough for creating the hibernation
* image.
*/
nr_freed_pages = shrink_all_memory(nr_shmem_pages);
pr_debug("requested to reclaim %lu shmem pages, actually freed %lu pages\n",
nr_shmem_pages, nr_freed_pages);
}
/**
* hibernation_snapshot - Quiesce devices and create a hibernation image.
* @platform_mode: If set, use platform driver to prepare for the transition.
@@ -425,14 +408,9 @@ int hibernation_snapshot(int platform_mode)
if (error)
goto Close;
/* Preallocate image memory before shutting down devices. */
error = hibernate_preallocate_memory();
if (error)
goto Close;
error = freeze_kernel_threads();
if (error)
goto Cleanup;
goto Close;
if (hibernation_test(TEST_FREEZER)) {
@@ -445,19 +423,13 @@ int hibernation_snapshot(int platform_mode)
}
error = dpm_prepare(PMSG_FREEZE);
if (error) {
dpm_complete(PMSG_RECOVER);
goto Thaw;
}
if (error)
goto Complete;
/*
* Device drivers may move lots of data to shmem in dpm_prepare(). The shmem
* pages will use lots of system memory, causing hibernation image creation
* fail due to insufficient free memory.
* This call is to force flush the shmem pages to swap disk and reclaim
* the system memory so that image creation can succeed.
*/
shrink_shmem_memory();
/* Preallocate image memory before shutting down devices. */
error = hibernate_preallocate_memory();
if (error)
goto Complete;
console_suspend_all();
pm_restrict_gfp_mask();
@@ -492,10 +464,10 @@ int hibernation_snapshot(int platform_mode)
platform_end(platform_mode);
return error;
Complete:
dpm_complete(PMSG_RECOVER);
Thaw:
thaw_kernel_threads();
Cleanup:
swsusp_free();
goto Close;
}