Drivers: hv: hv_balloon: refuse to balloon below the floor (530d15b9) · Commits · 戴 / test

When host asks us to balloon up we need to be sure we're not committing suicide by overballooning. Use already existent 'floor' metric as our lowest possible value for free ram. Signed-off-by:

Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by:

K. Y. Srinivasan <kys@microsoft.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/hv_balloon.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -1138,6 +1138,8 @@ static void balloon_up(struct work_struct *dummy)
		bool alloc_error;
		bool done = false;
		int i;
		struct sysinfo val;
		unsigned long floor;

		/* The host balloons pages in 2M granularity. */
		WARN_ON_ONCE(num_pages % PAGES_IN_2M != 0);
		@@ -1148,6 +1150,15 @@ static void balloon_up(struct work_struct *dummy)
		*/
		alloc_unit = 512;

		si_meminfo(&val);
		floor = compute_balloon_floor();

		/* Refuse to balloon below the floor, keep the 2M granularity. */
		if (val.freeram - num_pages < floor) {
		num_pages = val.freeram > floor ? (val.freeram - floor) : 0;
		num_pages -= num_pages % PAGES_IN_2M;
		}

		while (!done) {
		bl_resp = (struct dm_balloon_response *)send_buffer;
		memset(send_buffer, 0, PAGE_SIZE);

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